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1
Place, G. T., S. C. Reberg-Horton, D. L. Jordan, T. G. Isleib i G. G. Wilkerson. "Influence of Virginia Market Type Genotype on Peanut Response to Weed Interference". Peanut Science 39, nr 1 (1.01.2012): 22–29. http://dx.doi.org/10.3146/ps10-12.1.
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Abstract Differences in the ability of cultivars to compete with weeds are not well-defined for peanut. Research was conducted in 2007 and 2008 to compare the growth and competitiveness of the virginia market type cultivars NC 10C, NC-V 11, NC 12C, Phillips, VA 98R, and breeding lines N99027L, N01013T, and N02020J under weedy and weed-free conditions. Weed-free peanut was established by applying preemergence and postemergence herbicides throughout the growing season supplemented by weekly hand removal of weeds. Clethodim was applied to weedy peanut to eliminate annual grass interference but not interference from broadleaf weeds and sedges. Weed-free peanut biomass, weedy peanut biomass, and weed biomass were not affected by genotype 10 weeks after peanut emergence. Although substantial yield loss was noted in presence of weeds, the percent yield loss did not vary by genotype when comparing weedy and weed-free yield. These data suggest that cultivar selection within virginia market type peanut will have limited utility in a comprehensive weed management strategy.
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Mahajan, Gulshan, Mugalodi S. Ramesha i Bhagirath S. Chauhan. "Response of Rice Genotypes to Weed Competition in Dry Direct-Seeded Rice in India". Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/641589.
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The differential weed-competitive abilities of eight rice genotypes and the traits that may confer such attributes were investigated under partial weedy and weed-free conditions in naturally occurring weed flora in dry direct-seeded rice during the rainy seasons of 2011 and 2012 at Ludhiana, Punjab, India. The results showed genotypic differences in competitiveness against weeds. In weed-free plots, grain yield varied from 6.6 to 8.9 t ha−1across different genotypes; it was lowest for PR-115 and highest for the hybrid H-97158. In partial weedy plots, grain yield and weed biomass at flowering varied from 3.6 to 6.7 t ha−1and from 174 to 419 g m−2, respectively. In partial weedy plots, grain yield was lowest for PR-115 and highest for PR-120. Average yield loss due to weed competition ranged from 21 to 46% in different rice genotypes. The study showed that early canopy closure, high leaf area index at early stage, and high root biomass and volume correlated positively with competitiveness. This study suggests that some traits (root biomass, leaf area index, and shoot biomass at the early stage) could play an important role in conferring weed competitiveness and these traits can be explored for dry-seeded rice.
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Chase, Carlene A., Odemari S. Mbuya i Danielle D. Treadwell. "Water Infiltration in Fall Broccoli". HortScience 41, nr 4 (lipiec 2006): 998B—998. http://dx.doi.org/10.21273/hortsci.41.4.998b.
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The effect of living mulches (LM) on weed suppression, crop growth and yield, and soil hydraulic conductivity were evaluated in broccoli in North Central Florida at Citra and in North Florida at Live Oak, using organic production methods. `Florida 401' rye, `Wrens Abruzzi' rye, black oat, and annual ryegrass, were either mowed or left untreated and compared with weedy and weed-free controls. Cover crop biomass was highest with `Florida 401' at both locations, intermediate with black oat and `Wrens Abruzzi', and lowest with ryegrass. The greatest weed infestation occurred with the weedy control. In Citra, ryegrass decreased weed biomass by 21% compared with ≈45% by the other LM with no differences due to mowing. However, at Live Oak, mowed LM and the weedy control had similar amounts of weed biomass; whereas unmowed LM had 30% to 40% less weed biomass than the weedy control. At both locations, broccoli heights were greatest with the weed-free control, intermediate with the cover crops, and lowest with the weedy control. Total above-ground broccoli biomass and marketable weight of broccoli at Live Oak, and number of marketable heads at both locations, were unaffected by the LM. At Citra, total broccoli biomass with LM and the weedy control decreased in a similar manner, so that total broccoli biomass was highest with the weed-free control. Ryegrass and the weedy control suppressed marketable broccoli weight by 24%; however, greater decrease in marketable weight (39% to 43%) occurred with `Florida 401', `Wrens Abruzzi', and black oat. At both locations, mowing of LM had no effect on broccoli growth or yield. There was no difference in saturated hydraulic conductivity among treatments.
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Shahbazi, Saeed, Marjan Diyanat, Sareh Mahdavi i Soheida Samadi. "Broadleaf weed control in rain-fed chickpea". Weed Technology 33, nr 5 (13.08.2019): 727–32. http://dx.doi.org/10.1017/wet.2018.40.
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AbstractWeeds are among the main limitations on chickpea production in Iran. The efficacy of herbicide treatments including linuron PPI, imazethapyr PPI, PRE, and POST, pendimethalin PPI and POST, bentazon POST, pyridate POST, and oxadiazon POST along with one or two hand weedings were evaluated for weed control and yield response in rain-fed chickpea in Aleshtar, Lorestan, Iran in 2015 and 2016. Wild safflower, threehorn bedstraw, wild mustard, and hoary cress were the predominant weed species in both experimental years. Total weed dry biomass in weedy check plots averaged 187 and 238 g m−2 in 2015 and 2016, respectively, and weed density and biomass were reduced in all treatments compared to the weedy check in both years. Treatments composed of pyridate followed by one hand weeding or imazethapyr POST followed by two hand weedings resulted in the lowest weed biomass. The presence of weeds reduced yield by 74% and 66% in the weedy check plots compared to the weed-free control plots in 2015 and 2016, respectively. Application of oxadiazon, bentazon, and imazethapyr PPI, PRE, and POST resulted in lower chickpea yields. All herbicides tested injured chickpea slightly, with pyridate causing the least injury.
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Rezvani, M., F. Zaefarian i M. Jovieni. "Weed suppression ability of six soybean [Glycine max (L.) Merr.] varieties under natural weed development conditions". Acta Agronomica Hungarica 61, nr 1 (1.03.2013): 43–53. http://dx.doi.org/10.1556/aagr.61.2013.1.5.
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The weed suppression ability of different soybean varieties was studied in a field experiment in 2010. The experiment was carried out in a randomized complete block design using a split-plot arrangement with 3 replicates. The main plots were either weedfree (hand weeding) or infested with the natural weed population (weedy). Six soybean varieties (Sari, Telar, Sahar, Hill, 032 and 033) were randomized within the main plots. The relative biomass total (RBT), relative crowding coefficient (RCCcw) and competitive balance index (Cb) were recorded and were regressed against crop traits under weedy conditions. The results showed a reduction in the maximum height of the soybean varieties under weedy conditions. No significant relationship was found between weed biomass and the canopy height of the varieties. Competition indices and the weed suppressive ability of soybean showed intergenotypic variation in competitive ability between the varieties tested. Weed pressure reduced the yield and yield components of all the soybean varieties. Under weedy conditions the soybean variety Hill gave a higher economic yield than the others, with high weed biomass suppression ability.
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Bordelon, Bruce P., i Stephen C. Weller. "Cover Crop Effects on Weed Control and Growth of First-year Grapevines". HortScience 30, nr 4 (lipiec 1995): 801E—801. http://dx.doi.org/10.21273/hortsci.30.4.801e.
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Four cover crops were evaluated for weed control and effects on first-year vine growth. Winter wheat (cv. Cardinal), rye (cv. Wheeler), oats (cv. Ogle), and hairy vetch (no cultivar name) were either fall- or spring-planted and compared to cultivated and weedy control plots. Cover crop and weed biomass dry weight was collected twice during the growing season. Vines (Vitis labrusca cv. Steuben) were planted in the spring and destructively sampled at the end of the growing season for analysis of leaf area, leaf number, shoot length., shoot number, top growth dry weight, and root system dry weight. None of the vines in cover crop treatments had growth as good as vines in the weed-free check. Vines in the best cover crop treatments had ≈70% as much leaf area, 75% as many leaves, 50% as much shoot dry weight, and 40% as much root dry weight as vines in the weed-free check. Cover crop biomass dry weight and vine growth was greater in fall-planted plots than in spring-planted plots. Despite low cover crop biomass dry weight, spring-planted plots had few weeds (low weed biomass dry weight). However, vine growth in spring-planted plots was not significantly different than vine growth in the weedy check.
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Rasool, Ghulam, Gulshan Mahajan, Rajpaul Yadav, Zarka Hanif i Bhagirath Singh Chauhan. "Row spacing is more important than seeding rate for increasing Rhodes grass (Chloris gayana) control and grain yield in soybean (Glycine max)". Crop and Pasture Science 68, nr 7 (2017): 620. http://dx.doi.org/10.1071/cp17229.
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In Australia, soybean (Glycine max (L.) Merr.) is planted at a low density in wide rows, and weeds substantially reduce yield because of opportunities for their growth in the wide rows. Field studies were conducted over 2 years at the University of Queensland farm, Gatton, Australia, to assess the effect of row spacing and seeding rate on the competitiveness of soybeans with a model weed, Rhodes grass (Chloris gayana Kunth). The experiment was conducted in a split-split plot design, replicated three times. Main plots comprised two seeding rates (40 and 80 kg ha–1), subplots two row spacings (25 and 75 cm), and sub-subplots four Rhodes grass infestation periods (weedy from planting to maturity, weedy from 3 weeks after planting (WAP) to maturity, weedy from 6 WAP to maturity, and weed-free from planting to maturity). The results showed that seed rate did not influence Rhodes grass biomass or soybean yield. Soybean yield was greater and Rhodes grass biomass was less in the 25-cm rows than the 75-cm rows. For the 25-cm rows, Rhodes grass biomass in the plots infested beyond 3 WAP was 81–89% less than in the season-long weedy plots, whereas for the wider row crop, this reduction was only 60–75%. For the 25-cm rows, soybean yield in the plots infested with Rhodes grass beyond 3 WAP was 30–36% less than under weed-free condition. However, for the 75-cm rows, this reduction was 56–65%. The results suggest that planting soybean in wider rows caused greater reduction in yield and required an earlier weed management program than planting in narrow rows. The study also suggested that narrowing row spacing was more important than increasing seeding rates for improving weed control and soybean grain yield.
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Kubota, Hiroshi, Sylvie A. Quideau, Pierre J. Hucl i Dean M. Spaner. "The effect of weeds on soil arbuscular mycorrhizal fungi and agronomic traits in spring wheat (Triticum aestivumL.) under organic management in Canada". Canadian Journal of Plant Science 95, nr 4 (lipiec 2015): 615–27. http://dx.doi.org/10.4141/cjps-2014-284.
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Kubota, H., Quideau, S. A., Hucl, P. J. and Spaner, D. M. 2015. The effect of weeds on soil arbuscular mycorrhizal fungi and agronomic traits in spring wheat (Triticum aestivum L.) under organic management in Canada. Can. J. Plant Sci. 95: 615–627. Understanding the influence of weeds in agroecosystems may aid in developing efficient and sustainable organic wheat production systems. We examined the effect of weeds on soil microbial communities and the performance of spring wheat (Triticum aestivum L.) under organic management in Edmonton, AB, Canada. We grew 13 Canadian spring wheat cultivars in organically managed hand-weeded less-weedy and weedy treatments in 2010 and 2011. The less-weedy treatment exhibited greater grain yield and tillers per square meter, while kernel weight, test weight, days to maturity, plant height, grain P and protein content were not altered by weed treatment. Canada Western Red Spring (CWRS) wheat cultivars CDC Go and CDC Kernen were the most yield-stable because they minimized fertile tiller reduction in response to weed pressure (10 and 13% reduction, respectively, compared with the average reduction of 20%). Other cultivars exhibited yield stability through increased kernel weight. The contribution of arbuscular mycorrhizal fungi (AMF) to the total phospholipid fatty acid increased in both treatments; however, the rate of this increase was greater in the weedy treatment than the less-weedy treatment (from 2.9 to 3.9%, from 2.8 to 3.1%, respectively). Weed dry biomass was positively correlated with AMF% in the less-weedy treatment only. Organic systems tend to be weedier than conventional systems. We found that weeds are important determinants of AMF proliferation in soil. In addition, choosing wheat cultivars that maintain important yield components under severe weed stress is one strategy to maximize yields in organic systems.
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Ahmadi, Abdol Reza, Saeed Shahbazi i Marjan Diyanat. "Efficacy of Five Herbicides for Weed Control in Rain-Fed Lentil (Lens culinaris Medik.)". Weed Technology 30, nr 2 (czerwiec 2016): 448–55. http://dx.doi.org/10.1614/wt-d-15-00125.1.
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Lentil is vulnerable to weed competition because of its short stature, slow establishment, and limited vegetative growth. Although the vast majority of lentil production is under rain-fed conditions, there is a little published information on weed control with herbicides in rain-fed lentils. Field experiments were conducted to determine the efficacy of nine herbicide treatments including fomesafen, imazethapyr, linuron, pendimethalin, and pyridate alone or in combination compared with one or two hand weeding(s) on weed control and yield response in rain-fed lentil in Khorramabad, Iran in 2012 and 2013. Weed species included catchweed bedstraw, cowcockle, haresear mustard, hoary cress, wild mustard, and wild safflower. Total weed dry biomass in weedy check plots averaged 156 and 170 g m−2 in 2012 and 2013, respectively, and weed density and biomass were reduced in all treatments compared to the weedy check in both years. Plots that were hand weeded twice reduced weed biomass the greatest, whereas fomesafen, linuron, or one hand weeding did not control weeds satisfactorily. Noncontrolled weeds reduced lentil yield by 67% both years compared to the weed-free control. Lentil yield in 2013 (1,370 kg ha−1) was higher than in 2012 (1,150 kg ha−1). All herbicides tested injured lentil slightly, with pyridate (1,200 g ai ha−1) and pendimethalin (660 g ai ha−1 plus imazethapyr at 250 to 500 g ai ha−1) causing the least injury. Across all treatments, imazethapyr plus pendimethalin PRE, pyridate POST, and two hand-weeding treatments had the best performance for weed control and lentil yield.
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Awoke Mensa, Teshale Wube i Tariku Simion. "Effect of weed control methods on weed biomass and grain yield of maize (Zea mays L.) under rainfed condition in Basketo Special District, Southern Ethiopia". International Journal of Science and Research Archive 9, nr 1 (30.05.2023): 168–73. http://dx.doi.org/10.30574/ijsra.2023.9.1.0362.
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Maize (Zea mays L.) is a major crop grown in Basketo Special district by smallholder farmers. However, its production and productivity is challenged by many factors of which weeds are the key factor that reduce the productivity of maize in the district. Therefore, field experiment was conducted at Basketo Special district during 2017 main cropping season under rainfed condition to evaluate weed control methods on weed biomass and grain yield of maize. The experiment consisted of six treatments namely; once hand hoeing at 20 days after crop emergence (DACE), twice hand hoeing at 20 and 40 DACE, Primagram Gold 660SC + once hand hoeing at 40 DACE, Primagram Gold 660SC + twice hand hoeing at 40 and 60 DACE, farmer practice and weedy check. It was laid-out in Randomized Complete Block Design with four replications. Weed and crop parameters were collected. The highest maize grain yield and the lowest weed biomass were obtained from Primagram Gold 660SC + twice hand hoeing without significant difference with Primagram Gold 660SC + once hand hoeing whereas the lowest grain yield and highest weed biomass were found in weedy check. Moreover, the results revealed that integration of Primagram Gold 660SC with once (at 40 DACE) and twice (at 40 and 60 DACE) hand hoeing significantly reduced weed density and biomass and gave better maize grain yield and maximize net benefit. Therefore, these two treatments could be recommended to improve maize productivity and net income of the farmers in the study area.
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Bussan, Alvin J., Orvin C. Burnside, James H. Orf, Eric A. Ristau i Klaus J. Puettmann. "Field evaluation of soybean (Glycine max) genotypes for weed competitiveness". Weed Science 45, nr 1 (luty 1997): 31–37. http://dx.doi.org/10.1017/s0043174500092444.
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In the first of 2 field studies, weed biomass and soybean seed yield were used to evaluate 16 soybean genotypes for competitive ability against 12 weed species at Rosemount, MN, in 1992 and 1993. The yield and ranking of soybean genotypes often varied with the weed species. Grass weed species reduced yields the most, and small-seeded broadleaf weeds reduced yields the least across years. ‘Parker’ was highly competitive, as it suppressed weed biomass and produced high soybean yield. ‘Kato,’ ‘Kasota,’ ‘Dawson,’ and ‘Glenwood’ minimized weed biomass and maintained soybean yield while in competition with grass weeds but yielded poorly relative to other soybean genotypes in weed-free conditions. ‘Lambert’ produced high soybean yield in weed-free conditions, but yield dropped markedly when in competition with grass weeds. ‘Grande,’ ‘Heifeng 25,’ and ‘Norman’ soybeans were poor competitive genotypes in weedy situations and low yielding in weed-free conditions. A 2nd field study conducted at Rosemount and St. Paul, MN, during 1993 evaluated 16 soybean genotypes under 4 levels and durations of weed pressure for weed competitiveness. Parker, ‘Sturdy,’ and M89-794 were most competitive in suppressing weed biomass and producing high yields. Lambert yielded fairly well but allowed high weed biomass. M89-1743, M89-1006, ‘Archer,’ and ‘Ozzie’ yielded poorly and did not sup press weed biomass production. No relationship was found between weed competitiveness and soybean canopy area, height, and volume measured 30–45 d after planting (DAP).
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Fedoruk, L. K., E. N. Johnson i S. J. Shirtliffe. "The Critical Period of Weed Control for Lentil in Western Canada". Weed Science 59, nr 4 (grudzień 2011): 517–26. http://dx.doi.org/10.1614/ws-d-11-00051.1.
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Weed control in lentil is difficult because lentil is a poor competitor with weeds and few POST broadleaf herbicides are available. Imadazolinone-tolerant lentils have more herbicide options, but the optimum timing for herbicide application is not known. The critical period of weed control (CPWC) is the period in a crop's life cycle when weeds must be controlled in order to prevent yield loss. The objective of this research was to determine the CPWC for lentil. We made lentil remain weedy or weed-free from 0 to 11 aboveground nodes to investigate the durations of weed interference and weed-free period, respectively. It was found that lentil has a CPWC beginning at the five-node stage and continuing to the 10-node stage. There was an inverse relationship between weed biomass and lentil yield; that is, lentil yield was highest when weed biomass is minimal. We propose that the CPWC begins when weeds start to accumulate significant biomass and ends with crop canopy closure. Therefore, to maximize lentil yields, growers should consider using a POST residual herbicide that can control weeds during the CPWC.
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Shahabuddin, M., MM Hossain, M. Salim i M. Begum. "Efficacy of pretilachlor and oxadiazon on weed control and yield performance of transplant Aman rice". Progressive Agriculture 27, nr 2 (17.08.2016): 119–27. http://dx.doi.org/10.3329/pa.v27i2.29320.
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Two experimentswere carried out at the Agronomy Field laboratory, Bangladesh Agricultural University, Mymensingh during July to December 2014 to study the effectiveness of pretilachlor and oxadiazon on weed control and yield performance oftransplant aman rice. In experiment I BRRI dhan31and in experiment II BRRI dhan46 was transplanted with eight weeding practices viz., weedy check; one hand weeding; two hand weeding; weed free;Pretilachlor only;Oxadiazon only;Pretilachlor + one hand weeding; and Oxadiazon+ one hand weeding. The design was split-plot with three replications. Eleven weed species were found to be infested in the experimental plots. Although weeds were completely controlled in weed free treatment, it is not practicable.Pretilachlor oroxadiazon with one hand weeding performed the best in terms of weed density and weed biomass over single application of each and even manual weeding. Weeds were completely resistant to weedy check, poorly susceptible to one hand weeding, moderately susceptible to two hand weeding and single application of both herbicide and highly susceptible to both herbicides with one hand weeding while weeds were completely susceptible to weed free treatment. Herbicides produced slight phyto-toxicity which was recovered by two weeks of application. The highest grain yield was recorded from weed free treatment and was statistically identical to pretilachlor oroxadiazon with one hand weeding. Single application of pretilachlor oroxadiazon ranked the third in terms of yield and statistically similar to two hand weeding followed by one hand weeding. Weedy check performed the worst.Progressive Agriculture 27 (2): 119-127, 2016
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Nazir, Aijaz, Mohammad Anwar Bhat, Tauseef Ahmad Bhat, Suhail Fayaz, Mohammad Salim Mir, Umar Basu, Shafat Ahmad Ahanger i in. "Comparative Analysis of Rice and Weeds and Their Nutrient Partitioning under Various Establishment Methods and Weed Management Practices in Temperate Environment". Agronomy 12, nr 4 (27.03.2022): 816. http://dx.doi.org/10.3390/agronomy12040816.
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A research trial was conducted at Agronomy Farm (SKUAST-K, Wadura, Jammu & Kashmir), during kharif 2017 and 2018 to evaluate nutrient removal in rice under various rice establishment methods and weed control measures. The study comprised of two factors: rice establishment techniques {Transplanting (TPR); Direct seeding (DSR) and System of rice intensification (SRI)} as main plot treatments and weed control measures {Butachlor @ 1500 g a.i ha−1 (B); Penoxsulam @ 22.5 g a.i ha−1 (P); Pyrazosulfuron ethyl + Pretilachlor @ 15 and 600 g a.i ha−1 (PP); Bensulfuron methyl + Pretilachlor @ 60 and 600 g a.i ha−1 (BP); 2 Conoweeding/Hand Weeding (CW/HW); Weed free (WF) and weedy check (WC)} as sub-plot treatments meant to evaluate the best establishment method and weed management practice for rice. Over DSR and transplanted rice, the SRI technique yielded a significant increase in dry biomass accumulation (17.04 and 17.20 t ha−1) and grain (7.92 and 8.17 t ha−1) and straw (9.60 and 10.17 t ha−1) yields. Penoxsulam herbicide significantly showed higher grain and straw yield of 8.19 and 8.28 t ha−1 and 10.13 and 10.44 t ha−1, respectively, than other weed management measures by comparing the means using critical difference. TPR excelled in reducing dry weed biomass more than other established methods. All herbicides considerably reduced dry weed biomass, but Penoxsulam herbicide showed the greatest reduction in dry weed biomass and proved superior against complex weed flora. Weeds showed maximum contribution towards total Biomass under DSR, among rice establishment techniques. In contrast, among different weed control measures, it was maximum in weedy check treatment (Untreated Control) and minimum in penoxsulam treatment. SRI significantly excelled in crop (grain and straw) nutrient uptake compared to the DSR and TPR method, although different crop establishment techniques non-significantly influenced nutrient concentrations. Furthermore, penoxsulam treatment demonstrated higher crop (grain and straw) nutrient uptake among the various weed management measures. However, available soil nutrients were observed among establishment techniques, highest in DSR and lowest in SRI. Moreover, direct-seeded rice excelled SRI and transplanted rice in weed nutrient uptake, and among the different herbicidal treatments, penoxsulam recorded the lowest uptake in weeds. Nutrient budgeting demonstrated that DSR showed the maximum percentage of nutrient removal by weeds, and the minimum ratio was in TPR. In contrast, the lowest rate of nutrients removed via weeds were seen in penoxsulam application under various weed management measures.
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Malik, Vikram S., Clarence J. Swanton i Tom E. Michaels. "Interaction of White Bean (Phaseolus vulgarisL.) Cultivars, Row Spacing, and Seeding Density with Annual Weeds". Weed Science 41, nr 1 (marzec 1993): 62–68. http://dx.doi.org/10.1017/s0043174500057593.
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Field experiments were conducted at the Elora Research Station, Elora, Ontario, in 1988 and 1989 to quantify the inherent competitive ability of three white bean cultivars: OAC Gryphon, OAC Sprint, and OAC Laser growing with a naturally occurring population of annual weeds. An attempt was made to increase the competitive ability of these cultivars by altering row spacing and seeding density. Uncontrolled populations of weeds reduced white bean yields by 70%. OAC Gryphon and OAC Laser reduced weed biomass by 10 to 35% compared to OAC Sprint. The ability of cultivars to reduce weed biomass was further enhanced in medium and narrow rows compared to traditional wide rows. Cultivar, row spacing, and seeding density combinations which maximized leaf area index when grown under weedy conditions also had significantly less weed biomass. However, cultivar selection, row spacing, and seeding density did not reduce weed density. A significant negative correlation was observed between weed biomass accumulation and final yield of white bean. For each kg ha−1increase in weed biomass the corresponding white bean yield loss averaged 0.380 kg ha−1. Season-long weed competition significantly reduced total number of pods per plant, number of seeds per pod, and 100-seed weight.
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Karn, Elizabeth, Teresa De Leon, Luis Espino, Kassim Al-Khatib i Whitney Brim-DeForest. "Effects of competition from California weedy rice (Oryza sativa f. spontanea) biotypes on a cultivated rice variety". Weed Technology 34, nr 5 (25.03.2020): 666–74. http://dx.doi.org/10.1017/wet.2020.35.
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AbstractWeedy rice is an emerging problem of cultivated rice in California. Infestations of weedy rice in cultivated rice result in yield loss and reduced grain quality. In this study, we aimed to evaluate growth and yield components of a widely grown cultivated rice variety in California in response to weedy rice competition. Greenhouse competition experiments in an additive design were conducted in 2017 and 2018 to determine the growth and yield components of ‘M-206’ rice and five weedy rice biotypes found in California at varying weed densities. M-206 rice initially grew at a faster relative growth rate of 0.53 cm−1 wk−1 under competitive conditions compared with 0.47 cm−1 wk−1 in the absence of weedy rice, but absolute and relative growth rates declined more rapidly under competitive conditions as plants approached maturity. At harvest, M-206 plant height was reduced 13% under competitive conditions, and M-206 tiller number was reduced 23% to 49%, depending on the weedy rice biotype it was competing with. Except for 100-grain weight, the growth traits and grain yield components of M-206 rice were reduced with increasing density of weedy rice. At the highest weed density measured, 40 plants m−2, M-206 rice had yield losses of 69% grain yield plant−1, 69% panicle weight, 59% fresh and dry biomass, 55% grain yield panicle−1, and 54% panicle number. The five evaluated weedy rice biotypes varied widely in early growth rates, height, biomass production, and grain yield, indicating differing competitive strategies. Most weedy rice biotypes produce plants with greater plant height, tiller number, panicle number, and above- and below-ground biomass compared with cultivated rice. Weedy rice biotypes produced 45% to 57% higher grain yield per plant than M-206 rice under competitive conditions.
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Chauhan, Bhagirath S., i David E. Johnson. "Weedy Rice (Oryza sativa) I. Grain Characteristics and Growth Response to Competition of Weedy Rice Variants from Five Asian Countries". Weed Science 58, nr 4 (grudzień 2010): 374–80. http://dx.doi.org/10.1614/ws-d-09-00071.1.
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Weedy rice is a serious weed of cultivated rice in most of the rice-growing areas of the tropics and yet, despite its importance as a weed, limited information is available on its biology in Asia. A study was conducted to determine the seed characteristics and growth response to competition of weedy rice variants from five Asian countries (India [IWR], Malaysia [MWR], Philippines [PWR], Thailand [TWR], and Vietnam [VWR]) when grown alone or with either 4 or 12 cultivated rice (‘IR72’) plants. Seed characteristics including weight, length, width, and presence and length of awn differed between weedy rice variants. PWR had the heaviest seed (25 mg seed−1). Growth of weedy rice plants differed among variants and, generally, VWR grew the fastest. IR72 interference greatly reduced tiller and leaf numbers, leaf area, and shoot biomass of all weedy rice variants. At 8 wk after sowing, for example, shoot biomass of weedy rice variants in competition with 12 IR72 plants was 13 to 30% of that where plants were grown alone. TWR plants were shorter than those of other variants at all levels of crop interference. These results show that there are considerable differences among Asian weedy rice variants and yet, competition from the rice crop greatly suppresses weedy rice growth. This suggests that measures to ensure a competitive crop should be an important component of control strategies.
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Tadesse, Dejene, i Ano Wariyo. "Determination of Critical Weed Competition Period for Stevia rebaudiana Cultivation". Scholars Journal of Agriculture and Veterinary Sciences 9, nr 1 (30.01.2022): 9–13. http://dx.doi.org/10.36347/sjavs.2022.v09i01.002.
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The experiment was conducted during 2019/2020 at Wondogenet agricultural research center, Sidama region Ethiopia. It was initiated to find a critical weed competition period for Stevia rebaudiana production as weed management plays a great role in agriculture. The experiment was arranged in a randomized complete block design (RCBD) and consisted of three replication and fourteen treatments. Stevia rebaudiana growth and yield, as well as weed data, were assessed during the experiment and subjected to ANOVA using SAS computer software version 9.3, and differences between means were assessed at 5% probability level. Stevia plant height, branch number, and leaf yield were affected significantly due to treatments effects. Weed-free season treatment showed significantly higher stevia fresh yield (6.1 ton/ha) and dry yield (1.20 ton/ha) which was similar to the significantly higher results of the weedy for fifteen days after transplanting. Variation in the weedy period from fifteen days after transplanting (15DAT) to thirty days after transplanting (30DAT) resulted in 33.27% fresh stevia leaf yield reduction and 44.40% dry stevia leaf yield reduction. Weedy season treatment was used as a check and showed significantly lower stevia leaf yield which was also similar to the results of the weedy period for ninety days after transplanting (90DAT). On the other hand, the weedy period for fifteen days after transplanting (15DAT), the weed-free period for ninety days after transplanting (90DAT), and weed-free season treatments showed similar significantly lower weed density. An increase in the weedy period showed higher weed density and weed biomass results. Therefore, as weeds greatly affect stevia growth and yield, early weeding at 15DAT is important and recommended based on the present finding, however, for comprehensive results the experiment should be repeated over site and year.
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Eberlein, Charlotte V., Paul E. Patterson, Mary J. Guttieri i Jeffrey C. Stark. "Efficacy and Economics of Cultivation for Weed Control in Potato (Solanum tuberosum)". Weed Technology 11, nr 2 (czerwiec 1997): 257–64. http://dx.doi.org/10.1017/s0890037x00042925.
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A 3-year study was conducted in irrigated potato to compare weed control efficacy and economics of hilling plus one or two cultivations with the standard treatment of hilling plus a preemergence application of pendimethalin plus metribuzin. Trials were conducted under both weedy and weed-free conditions. Common lambsquarters and redroot pigweed were present in weedy treatments each year; significant populations of hairy nightshade and green foxtail also were present one year. When weed populations were low or moderate (< 45 plants/m2), total weed biomass in the hilling plus one cultivation treatment was reduced 98 to 99% relative to the weedy control, and U.S. No. 1 tuber yields were equal to the standard treatment. However, when weed populations were high (145 plants/m2), hilling plus one cultivation and hilling plus two cultivations provided only 30% and 61% reduction in weed biomass, respectively, and U.S. No. 1 tuber yields were 35% and 13% less, respectively, than the standard treatment. The standard treatment provided 99% reduction in total weed biomass each year, and yields were equal to the weed-free, hill plus no cultivation control. Net return was $37 to $100/ha higher for the hilling plus one cultivation treatment compared to the standard treatment when weed populations were moderate or low, but was $808/ha less than the standard treatment when weed populations were high.
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Nadeem, Muhammad Ather, Bilal Ahmad Khan, Asim Riaz Chadar, Rizwan Maqbool, Ali Raza, Muhammad Mansoor Javaid, Athar Mahmood, Muhammad Ishfaq Khan, Masood Ahmad i Muhammad Irfan. "Weed control and sustainable rice production through rice intensification system and conventional practices of weed competition periods and age of transplanted seedlings". Semina: Ciências Agrárias 43, nr 5 (17.11.2022): 2271–92. http://dx.doi.org/10.5433/1679-0359.2022v43n5p2271.
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Rice is an important cereal crop of global interest based on its daily uses. It was observed that the average yield of rice is low than its potential production due to the traditional growing techniques and weed intensification. Recently, the rice intensification system (RIS) has emerged as an alternative to the conventional rice cultivation system. A two-year field study was carried out to investigate the impact of seedling age (14, 21 & 28 days) and the weed competition periods (weedy check, 20, 40, 60, 80 DAT and weed-free throughout the growing season) in rice cultivated through RIS. Weedy check and weed-free for the growing season were kept as a control treatment. The results of our study revealed that a maximum dry weight (108.7 and 111.79 gm-2) and weeds density (101.7 and 110.6 plants m-2) of weed recorded in weedy check plot where 28 days old seedlings was transplanted while minimum dry weight (11.01 and 10.3 gm-2) and weeds density (9.7 and 10.9 m-2) were achieved in plots where 21 days old seedlings were transplanted and remain weed free. It was noted that weed density and weed dry biomass were gradually increased with increasing weed competition period at all ages of the rice seedling. Purple nutsedge (C. rotundus) exhibited maximum relative proportion in total weed’s density and dry biomass and also ranked first by weed summed dominance ratio (WSDR). Agronomic yield and yield contributing traits such as number of fertile tillers per hills (58.1 and 56.0), plant height (130.5 cm and 125.6 cm), kernels per plant (186.4 and 179.4), straw yield (7.8 t ha-1 and 7.5 t ha-1) and kernel yield (5.2 and 5.0 t ha-1) were maximum in plot that remained weed-free throughout the growing season with a seedlings age of 21 days during 2010 and 2011 respectively. Percent yield losses were minimum in plots with 21 days old seedling transplantation and at 20 days of weed competition period. Hence, present study concludes that 21 days old fine rice seedlings should be transplanted and weeds should be controlled within 20 DAT under SRI for effective weed control to avoid yield losses.
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NAEEM, M., A. MAHMOOD, M. Z. IHSAN, I. DAUR, S. HUSSAIN, Z. ASLAM i S. A. ZAMANAN. "Trianthema portulacastrum and Cyperus rotundus Interference in Maize and Application of Allelopathic Crop Extracts for Their Effective Management1". Planta Daninha 34, nr 2 (czerwiec 2016): 209–18. http://dx.doi.org/10.1590/s0100-83582016340200002.
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ABSTRACT Horse purslane (Trianthema portulacastrum) and purple nutsedge (Cyperus rotundus) are two noxious C4 weeds of maize crop causing extensive yield losses. A two years field experiment was performed to estimate interference of T. portulacastrum and C. rotundus and to evaluate the role of allelopathic water extracts for effective weed management in maize. Five plant water extracts in ten binary combinations were foliar applied in triplicated randomized complete block design. Plots treated with commercial herbicide atrazine and weedy check (control), were also maintained for comparison. The highest density of both weed species was observed at 45 days after sowing (DAS) while weed dry biomass was higher at 60 DAS. Binary combination of sorghum-sunflower depicted greater suppression for weed density, dry biomass and persistence index (88-92% for T. portulacastrum and 65-81% for C. rotundus) as compared with weedy check. This treatment combination has also recorded an enhancement of 125% in crop resistance index, 84% in leaf area index and 41% in crop growth rate at 60-75 DAS thus, leading to 51% improvement in grain yield. Binary combination of sunflower-brassica returned maximum marginal net benefit, while sorghum-maize combination anticipated the peak value for marginal rate of return. Along with the effective weed management and higher yield, sorghum-sunflower documented the maximum net economic benefits among different plant extract combinations therefore, suggesting that exogenous application of sorghum-sunflower extract can be effectively used for controlling these weeds in maize field.
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KOUSTA, Angeliki, Panayiota PAPASTYLIANOU, Nikolina CΗΕΙΜΟΝΑ, Ilias TRAVLOS, Ioanna KAKABOUKI i Dimitrios BILALIS. "Effect of Fertilization and Weed Management on Weed Flora of Hemp Crop". Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Horticulture 77, nr 2 (18.11.2020): 44. http://dx.doi.org/10.15835/buasvmcn-hort:2020.0013.
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Hemp is known to have a competitive advantage over weeds. Despite its suppressive ability, weed infestation remains an important issue during the early growth of the crop. The aim of this study was to determine the effect of fertilization and weed management on weed flora and hemp growth parameters during initial growth in the 2019 season. The experiment was laid out in a split-split plot design with three replicates: three hemp cultivars as main plots, three fertilization treatments as sub-plots and two sub-sub-plots (weedy, weed free). For the computation of height and biomass weight, 10 plants were randomly selected in each plot. Weed species were collected by quadrate and density and biomass weight were determined. ANOVA revealed that all factors and their interactions significantly affected plant traits. Hemp cultivars showed different competitive ability. ‘Futura 17’ reduced weed measurement traits better than ‘Uso 31’. Density and biomass of nitrophilous weeds increased with the higher N dose compared to control (up to 56% and 79% respectively), therefore negatively affecting the growth of the hemp plants. Further research is needed in order to identify useful information on interactions between weeds and hemp crop to address potential yield losses under different weed management systems.
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Kathiresan, Ramanathan, i Sangeeviraman Vishnudevi. "Rice farming components for biological weed control in transplanted rice: perspective on weedy rice management". Weed Science 69, nr 5 (2.08.2021): 609–14. http://dx.doi.org/10.1017/wsc.2021.53.
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AbstractFarming elements other than the crop, when integrated into the system, are supplementary, with multifold uses that include weed and pest management. Elements such as fish and poultry birds are integrated with transplanted wetland rice (Oryza sativa L.) for ensuring farmers’ livelihoods and the nutritional security and sustainability of the system. Integrated animal components such as poultry birds and fish also supplement the system with weed control. The role and efficacy of these animal components as tools for managing weedy rice (Oryza sativa L.) were explored, as weedy rice infestation is increasing. This threat of weedy rice is due to scarcity of water resulting from poor water management and improper field leveling. Grass carp (Ctenopharyngodon idella val.) produced the highest reduction of weedy rice biomass, 28% within 24 h under laboratory conditions. Polyculture of C. idella, mrigal (Cirrhinus mrigala Ham.), and silver carp (Hypophthalmichthys molitrix val.) reduced the biomass of weedy rice by 21% within 24 h. In laboratory studies, poultry manure at the highest concentration of 5% reduced the weedy rice seed germination 100% compared with rice seed germination at 91%. This conformed with microplot experiments in which poultry manure at 15.6 g d−1 resulted in a weed control index (WCI) of 8% in both years. However, poultry manure at 15.6 g d−1 in combination with herbicide application resulted in the highest control indices of weedy rice: 52% in 2017 and 2018. Integrating fish and poultry with PRE application of oxyfluorfen (0.25 kg ha−1) resulted in the highest WCI and grain yield in field experiments.
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Kousta, Angeliki, Panayiota Papastylianou, Ilias Travlos, Antonios Mavroeidis i Ioanna Kakabouki. "Effect of Fertilization and Weed Management Practices on Weed Diversity and Hemp Agronomic Performance". Agronomy 13, nr 4 (5.04.2023): 1060. http://dx.doi.org/10.3390/agronomy13041060.
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The industrial hemp market is rapidly expanding, and best crop practices need to be assessed. This study aimed to determine the effect of fertilization and weed management on hemp crops and weed flora during the 2019 and 2020 growing seasons. Field experiments were laid out in a split–split plot design with three replicates: two hemp cultivars as main plots, three fertilization treatments as sub-plots, and three sub-sub-plots (weedy, weed-free, and herbicide application). For the computation of crop traits, 10 plants were randomly selected by each plot. Weed species were collected by quadrate for density and biomass weight determination. Increased fertilization rate positively affected plant height and dry biomass, while no impact was recorded on yield and yield components. The density and biomass of nitrophilous weeds were enhanced by fertilization, negatively affecting hemp growth. Marked differences were recorded on the competitive ability of cultivars since “Fedora 17” decreased the weed studied traits better than “Uso 31”. Herbicide application decreased the biomass of annual and perennial weeds by 38% and 13%, respectively, while it caused a reduction in hemp growth and yield of “Uso 31” plants. Further research should be conducted to address hemp yield losses under different cultural practices and weed control systems.
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Ilyas, Mohammad. "RESPONSE OF BITTER GOURD (Momordica charantia) TO CULTURAL AND CHEMICAL WEED CONTROL METHODS". JOURNAL OF WEED SCIENCE RESEARCH 27, nr 2 (30.09.2020): 343–47. http://dx.doi.org/10.28941/pjwsr.v26i3.851.
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Experiments were conducted at the farm of the University of Agriculture Peshawar in 2012 and 2013 to evaluate the effect of different weed control methods in bitter gourd. The treatments comprised of four mulches (Rumex crispus, Silybum marianum, news papers, and saw-dust), a herbicide i.e. Stomp 330 EC (pendimethalin) applied as pre-emergence, a hand weeding and a control treatment (weedy check). Data were collected on weed biomass, number of plants ha-1 and fruit weight. The parameters were significantly affected by the applied treatments during both the years. Weed biomass in 2012 and 2013 was the highest (2971 and 3595 kg ha-1, respectively in the weedy check treatments and lowest in hand weeded plots (68 and 83 kg ha-1) in 2012 and 2013, respectively. Moreover the effect of the mulching treatments and the herbicide treatment were statistically at par with each other and different from the weedy check. The highest number of plants ha-1 (9773 and 8077) and fruit weight plant-1 (756 and 657 g) were recorded in the hand weeded treatments in 2012 and 2013, respectively. Hand weeding was followed by the treatment of Stomp 330 EC with the respective values in the two years as 8834 and 7301 plants ha-1, and 667 and 580 g plant-1 in 2012 and 2013, respectively. Moreover, the performance of the mulching treatments was also significantly more effective than the weedy check plots. Mulches of S. marianum and R. crispus reduced the weed biomass to 1072 and 1615 kg in 2012 and 1297 and 1954 kg in 2013 as compared to the weedy control with weed biomass of 2971 and 3595 kg ha-1 in 2012 and 2013, respectively. The respective no. of plants ha-1 for the mulches of S. marianum and R. crispus were 8548 and 8489 in 2012 and 7065 and 7016 in 2013 whereas and the fruit weight plant-1 was 435 and 396 in 2012 and 378 and 344 g in 2013. Keeping in view the good performance of weed biomass as mulches, the cost of production and the environmental safety, the hand weeding and herbicide use cannot be preferred alone for use as weed management tools. Therefore, the herbicide use and hand weeding should be used only on casual basis or in emergency; and the mulching methods should be adopted in the long run as mulching method is not only good for weed control but also for maintaining the soil fertility, moisture conservation, and environmental safety.
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Malviya, Shreya, i Mukesh Kumar Saini. "Effect of Herbicide (Propaquizafop and Imazethapyr) on Weed Flora Associated with Blackgram in Central India". International Journal of Environment and Climate Change 13, nr 10 (19.08.2023): 675–86. http://dx.doi.org/10.9734/ijecc/2023/v13i102703.
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An experiment was conducted at Product Testing Unit, Department of Agronomy, JNKVV, Jabalpur to study the effect of application of propaquizafop and imazethapyr herbicide on weeds associated with blackgram. The experimental field was having mixed weed flora comprising of grassy as well as broad leaved weeds. Nine treatments comprised of four rates of application of propaquizafop+ imazethapyr at 47+70, 50+75, 53+80 and 56+85 g/ha and alone application of propaquizafop (100 g/ha), imazethapyr (100 g/ha), pendimethalin (1500 g/ha) and hand weeding twice at 20 and 40 DAS including weedy check, were laid out in Randomized Block Design with three replications. All herbicide treatments were applied in 500 liters of water per hectare, using flat fan nozzle as per the treatments. The dominant weed flora, species wise weed density, weed biomass, Weed control efficiency and weed index were recorded at different interval. The study revealed that the Echinochloa colona (29.39%) and Dinebra retroflexa (24.30%) were the found as dominant weeds in the field whereas, other monocot weeds like Cyperus iria (18.19%) and dicot weeds like Mullugo pentaphylla (12.23%), Eclipta alba (7.58%) and Alternanthera philoxeroides (8.31%) were also present in less numbers in blackgram under weedy check plots. Among the herbicidal treatments, activity of propaquizafop+imazethapyr mixture at the dose 53+80 and 56+85 g/ha emerged as effective control for the weeds associated with blackgram.
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Naeem, Muhammad, Shahid Farooq i Mubshar Hussain. "The Impact of Different Weed Management Systems on Weed Flora and Dry Biomass Production of Barley Grown under Various Barley-Based Cropping Systems". Plants 11, nr 6 (8.03.2022): 718. http://dx.doi.org/10.3390/plants11060718.
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Weeds are among the major issues responsible for reduction in yield and profit in any crop production system. Herbicides are the easiest and quickest solution of weeds; however, their frequent use exert negative consequences on environment, human health, and results in the evolution of herbicide-resistant weed species. Due to these reasons, alternative weed management methods that are less harmful to environment and human health are needed. This two-year study evaluated the impact of different weed management options, i.e., false seedbed (FS), allelopathic water extracts (AWE), chemical control (CC), weed-free (WF) weedy-check (WC) on weed spectrum in various barley-based cropping systems, i.e., fallow-barley (FB), maize-barley (MB), cotton-barley (CB), mungbean-barley (M*B), and sorghum-barley (SB). Data relating to density, diversity, and biomass production of weed species prevailing in the studied cropping systems were recorded. Interactive effect of weed management methods and barley-based cropping systems significantly altered weed diversity, and densities of individual, broadleaved, and grassy weeds. A total 13 weed species (ten broadleaved and three grass) were recorded during both years of study. The highest dry biomass, diversity, and density of individual, broadleaved, and grassy weeds were noted in WC treatment, whereas WF treatment resulted in the lowest values of these traits. Chemical control resulted in the highest suppression of weed flora and improved dry biomass production of barley followed by AWE. The SB cropping system with CC or AWE resulted in the least weed flora. The M*B cropping system with CC or AWE produced the highest dry biomass of barley. It is concluded that including sorghum crop in rotation and applying AWE could suppress weeds comparable to herbicides. Similarly, including mungbean in rotation and applying AWE could increase dry biomass production of barley. In conclusion, herbicides can be replaced with an eco-friendly approach, i.e., allelopathy and inclusion of sorghum crop could be helpful in suppressing weed flora.
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Bagheri, M., F. Zaefarian, B. Bicharanlou i H. Ghanizadeh. "A Study of Intercropping of Maize with Sweet Basil and Borage". Cercetari Agronomice in Moldova 47, nr 2 (8.07.2014): 13–28. http://dx.doi.org/10.2478/cerce-2014-0013.
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Abstract Intercropping is one of the environmental friendly ways to improve the use of resources and weed control. A field experiment was performed on maize intercropped with sweet basil and borage under weed free and infestation conditions. The experimental design was a factorial based on randomized complete block design with three replicates. Factors included weed infestation levels (weed free and weed infestated) and intercropping ratios (100:0, 75:25, 50:50, 25: 75, and 0:100, maize: sweet basil or borage). The intercroppping treatments decreased weeds biomass compared to the monocultures of borage and sweet basil. The weeds biomass and density in maize monoculture was lower than the monocultures of the other two plants. Under sole crop condition, the plants yield was higher than intercropping treatments. Weed interference decreased the yield of plants, while this decrease was less in intercropping treatments. Area-time equivalent ratio value showed that the ratios of 50:50 maize: sweet basil, maize: borage and 25:75 maize: borage provided the yield advantages of 11%, 11% and 36% under weed infestation, respectively. Also, area-time equivalent ratio values were higher in weed infestation compared to weed free treatments. The leaves essential oil of sweet basil under intercropping treatments, especially in weedy condition, was further than monocropping treatments. Intercropping of maize with sweet basil was more successful than intercropping with borage in reducing weeds biomass and density. In general, the intercropping of maize with sweet basil was more efficient compared to intercroppping with borage.
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Marino, Paul C., i Katherine L. Gross. "Competitive effects of conspecific and herbaceous (weeds) plants on growth and branch architecture of Populus xeuramericana cv. Eugenei". Canadian Journal of Forest Research 28, nr 3 (1.03.1998): 359–67. http://dx.doi.org/10.1139/x97-223.
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The influence of tree density (2 x 3, 1 x 2, and 0.5 x 1 m) and weed control (weedy vs. weed free) on the growth and branching architecture of Populus xeuramericana cv. Eugenei was examined in an experimental plantation in southwestern Michigan, U.S.A. In the presence of weeds, poplars were shorter (p < 0.0001), had a smaller basal diameter (p < 0.0001), initiated fewer branches (p = 0.0004), and had fewer living branches (p = 0.002), shorter branches (p < 0.0001), and branches that spread outward (p < 0.0001). Increasing tree density decreased poplar height (p < 0.0001), basal diameter (p < 0.0001), branch length (p = 0.0062), and the number of living branches (p < 0.0001). At high densities, branches spread outward at their origin (p = 0.0015) and then curved sharply upward (p = 0.002). At the highest planting density there was no difference in branching in plots with and without weed control. However, poplars in the weedy treatment were smaller than those in the weed-free treatment (p < 0.0001). Our results demonstrate that poplar growth and architecture can be influenced by competitors of very different stature. Weeds, in fact, have a greater effect on growth than conspecifics. As a result, poplars grown in the presence of weeds are stunted relative to poplars grown in the absence of weeds, even at the highest tree density where the competitive effects of poplars reduced weed biomass.
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Wall, D. A., i L. Townley-Smith. "Wild mustard (Sinapis arvensis) response to field pea (Pisum sativum) cultivar and seeding rate". Canadian Journal of Plant Science 76, nr 4 (1.10.1996): 907–14. http://dx.doi.org/10.4141/cjps96-152.
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Field studies were conducted at Morden, Manitoba from 1992 to 1995 and Wadena, Saskatchewan in 1995 to investigate the effect of cultivar selection and seeding rate on field pea competitiveness with wild mustard. Cultivars that had both long vines and rapid canopy development (leaf area index) were more competitive with wild mustard than those with short vines and slow canopy development. Cultivars differed markedly in their ability to suppress weed growth. Wild mustard density was affected in 2 of 4 yr by cultivar selection, while weed biomass was affected in 3 of 4 yr. Field pea yield losses under weedy conditions differed among cultivars and those cultivars that more effectively reduced wild mustard density or biomass had the lowest yield losses. Yield losses from wild mustard competition did not differ among cultivars when weed pressure was high and weeds emerged 1 wk before the crop. Seeding rate of Titan, a cultivar with long vine length, affected wild mustard biomass more than Trump, a cultivar with a short vine length. Key words: Competitiveness, leaf area index, yield
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ASHRAF, U., R. N. ABBAS, S. HUSSAIN, Z. W. MO, S. A. ANJUM, I. KHAN i X. R. TANG. "Consequences of Varied Planting Geometry and Early Post Emergence Herbicides for Crop-Weed Interventions in Rice Under Semi-Arid Climate". Planta Daninha 34, nr 4 (grudzień 2016): 737–46. http://dx.doi.org/10.1590/s0100-83582016340400014.
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ABSTRACT Adjustment of planting geometry along with reduced applications of herbicides can be a viable tool for effective weed management in rice. This present study has examined the effects of three planting geometries (20 cm x 20 cm, 20 cm x 10 cm and 10 cm x 10 cm); along with early post emergence herbicides, viz; bispyribac sodium 20% WP at 39.50 g a.i. ha-1, bispyribac sodium 100 SC at 39.50 g a.i. ha-1, cyhalofop-butyle 10% EC at 49.50 g a.i. ha-1, and penoxulam 240 EC at 15 g a.i. ha-1 on weed growth, and rice performance under semi-arid climate. A weedy check was maintained as control where no herbicide was applied. Results showed that the narrowest plant spacing (10 cm x 10 cm) effectively controlled weeds; however, it also resulted in reduced rice growth and yield. More weed infestation and a season-long weed growth in weedy check plots have damaged rice growth and yield performance. All herbicides were effective in reducing weed density and biomass; however, reductions were greatest for 10 cm x 10 cm spaced plants. Among different plant spacings, the highest grain yield (4.35 ton ha-1) was obtained from plots where rice was planted at 20 cm x 20 cm; while narrowest plant spacing led to reduced tiller production, panicle development, grains per panicle, 1000-grain weight, and grain yield, but increased sterility % and biological yield. Further, weed dry biomass was negatively correlated with grain and biological yield of rice at all spacings. Although narrow plant spacing was effective in controlling weeds, it also reduced rice productivity, suggesting the need for further studies to overcome intra-specific competition in narrow spaced rice plants through improved resource management.
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Abbas, Rana Nadeem, Asif Iqbal, Muhammad Aamir Iqbal, Omar M. Ali, Raees Ahmed, Raina Ijaz, Adel Hadifa i Brandon J. Bethune. "Weed-Free Durations and Fertilization Regimes Boost Nutrient Uptake and Paddy Yield of Direct-Seeded Fine Rice (Oryza sativa L.)". Agronomy 11, nr 12 (30.11.2021): 2448. http://dx.doi.org/10.3390/agronomy11122448.
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Under the changing climate, fertilization regimes and weed infestation management in aromatic direct-seeded fine rice (DSR) remain vital for curbing environmental hazards and ensuring food security. A multi-year field study was undertaken to appraise the influence of fertilization techniques and weed-free periods on weed dynamics, nutrient uptake and paddy yield in a semi-arid environment. Treatments included two fertilization methods (broadcasting and side placement) and five weed-free durations (20, 30, 40, 50 post-seeding days, DAS) along with a weed-free crop for a whole season. Weed competition for a season-long crop (weedy check) was maintained for each fertilizer application method. Our results revealed that the side placement of fertilizers resulted in a significantly lower weed density and biomass, even under season-long weed competition. The highest paddy yield was recorded for a crop without weeds, while weed-free duration of up to 50 DAS followed it. The uptake of nitrogen (N), phosphorus (P) and potassium (K) for a weed-free duration of up to 50 DAS were only 19%, 9% and 8%, respectively, as compared to the weedy check. The uptake of N, P and K by weeds in the broadcast method was 18%, 30% and 24% higher, compared to side-placed fertilizers. The period of 20–50 DAS remained critical in DSR as far as weed control was concerned. Thus, the side placement of fertilizers and controlling weeds for up to 50 days after rice sowing can be recommended for general adoption in semi-arid agro-ecological conditions.
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Colquhoun, Jed B., Christopher M. Konieczka i Richard A. Rittmeyer. "Ability of Potato Cultivars to Tolerate and Suppress Weeds". Weed Technology 23, nr 2 (czerwiec 2009): 287–91. http://dx.doi.org/10.1614/wt-08-062.1.
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Potato producers rely heavily on herbicides for the majority of weed control. However, recent occurrences of herbicide-resistant weed populations and the lack of new herbicide registrations have stimulated interest in alternative strategies. The choice of potato cultivars that can suppress or tolerate weed competition could be a component of an integrated weed management system to reduce reliance on herbicides. The competitive ability of 10 potato cultivars—‘Atlantic’, ‘Bannock Russet’, ‘Dark Red Norland’, ‘Goldrush’, ‘Rodeo’, ‘Russet Burbank’, ‘Russet Norkotah’, ‘Snowden’, ‘Superior’, and ‘Villetta Rose’—was evaluated in 2006 and 2007 in Hancock, WI. Weed competition treatments included (1) weedy throughout the season, (2) weed-free from emergence to 4 wk after emergence (WAE) by hand-weeding, and (3) weed-free by hand-weeding for the entire season. Potato cultivars did not differ in ability to reduce weed biomass. Early-season time of potato emergence and canopy closure, as well as weed competition treatments, were strongly related to potato tuber yield. In general, Bannock Russet yield relative to weed-free controls of the same cultivar was less than that of most other cultivars. Overall, Atlantic, Russet Burbank, Snowden, and Superior yields (relative to weed-free control yields) usually were greater than the yields of other cultivars under weedy conditions. Although the ability to suppress weeds was similar among cultivars, differences in yield among cultivars grown in the presence of weeds suggest differential tolerances of weed competition.
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Khan, IMTIAZ KHAN. "Dr IMPACT OF VARIOUS ORGANIC AND CULTURAL PRACTICES ON YIELD AND WEED MANAGEMENT IN OKRA (Abelmoschus esculanta L.)". JOURNAL OF WEED SCIENCE RESEARCH 28, nr 3 (31.03.2022): 53–61. http://dx.doi.org/10.28941/pjwsr.v28i1.1023.
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Weed management in okra field is one of the most challenging and expensive steps that ultimately reducing the productivity. A field experiment was conducted to evaluate impact of various organic and cultural practices on yield and weed management in okra crop at Agronomy Research Farm, The University of Agriculture, Peshawar, Pakistan during spring season 2021 in a Randomized Complete Block Design (RCBD) having three replications. The following treatments were applied to the experimental trail. T1=Parthenium Parthenium hysterophorus) weed extraction (120g/L), T2= Coco grass (Cyperus rotundus) weed extraction (120g/L), T3= Field bind weed (Convolvulus arvensis) weed extraction (120g/L), T4= Mulching (Eucalyptus leaves), T5= Mulching (News Paper), T6= Hand weeding (Once) 20 days, T7= Hand weeding (Twice) 20 &40 days, T8= Weedy check. Results shows that all the studied parameters of okra crop were significantly affected by all the applied treatments except number of flowers plant-1. Maximum weed fresh biomass (143.3g), weed dry biomass (42.2g), plant height (64.2cm), number of branches plant-1, (11), fruit length (11.73 cm), fruit diameter (1.8 cm) and yield (3246.6kg/ha) were noted in a Hand weeding (Twice) 20- & 40-days treatment followed by Hand weeding (Once) after 20 days, however the minimum values was noted in weedy check treatment except weed density which was found maximum in weedy check treatment. Hand weeding twice after 20 & 40 days of crop sowing was recommended to get in okra crop better yield.
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Hanan-Alipi, Ana María, Heike Vibrans, Rocío Vega-Frutis, Cecilia Rocío Juárez-Rosete, Roberto Valdivia-Bernal i Jesús Velázquez-Fernández. "Growth, reproduction and weediness: testing four related species on a gradient of synanthropy". Botanical Sciences 99, nr 1 (27.10.2020): 43–57. http://dx.doi.org/10.17129/botsci.2599.
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Background . The ability of weeds to thrive in the stressful environments created by human disturbance has been explained mainly by a set of life history traits, such as short life cycles, generalist habits, as well as early and sustained reproduction. However, the evidence that these traits are better represented in weeds than in related species of other environments is mixed. To explore the relationship between weeds and the life history traits, we used the fact that plants are weedy to different degrees because of the heterogeneous nature of environments produced by disturbance. In a group of four congeners, we studied some growth and reproduction parameters in relation to the degree of synanthropy of the species, determined previously.
Methods. In a common garden experiment, we compared relative growth rate, time to flowering, and biomass distribution between four species of the genus Melampodium (Asteraceae) that are weedy to different degrees.
Results. The most synanthropic species, M. divaricatum, stood out for its steady growth rate, but not for assigning more resources to reproduction, nor for early flowering. In general, we found no association between growth and reproductive parameters studied in the four Melampodium species and the degree to which they are weeds.
Conclusions. Results suggest that traits such as fast growth and early reproduction may not be essential for life as a weed. Rather, weedy species exhibit a complex pattern of growth traits that could be affected by conditions independent of anthropogenic disturbance.
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LEMIEUX, C., A. K. WATSON i J. M. DESCHÊNES. "WEED POPULATION DYNAMICS IN RECENTLY ESTABLISHED TIMOTHY STANDS: GROWTH AND PHYSIOGNOMY OF THE WEED COMPONENTS". Canadian Journal of Plant Science 67, nr 4 (1.10.1987): 1035–44. http://dx.doi.org/10.4141/cjps87-139.
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In two experiments conducted in the field between 1983 and 1985, timothy was established with or without barley, red clover, grassy weeds and broadleaf weeds. The plots were sampled during establishment and production years. At each sampling, the botanical composition was evaluated to characterize the weed populations. Throughout establishment, the weed populations were dominated by annual broadleaf and grassy weeds which, when growing separately, produced comparable amounts of biomass. However, when growing together, the grassy weeds were clearly dominated by the broadleaf weeds. During the subsequent production years, the weedy populations were dominated by perennial broadleaf weeds. Neither the structure of the weed populations, nor the short-term dynamics of the grassy weed populations were affected by the management system used. However, the short-term dynamics of the broadleaf weed populations were influenced by barley, red clover and the weed control treatments applied during the year of establishment. The use of barley accelerated the growth of the broadleaf weed populations while red clover delayed it. Subsequent broadleaf weed populations were noticeably larger in the plots where they were allowed to grow during the establishment year.Key words: Broadleaf weeds, grassy weeds, Phleum pratense, competition, short-term dynamics
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Gupta, Vikas, Brij Nandan Singh, Jai Kumar, Mahender Singh i Jamwal B S. "Effect of Imazathypr on Weed Control and Yield in Chickpea Under Kandi belt of Low Altitude Sub-tropical Zone of Jammu". Madras Agricultural Journal 99, March (2012): 81–86. http://dx.doi.org/10.29321/maj.10.100020.
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Field experiment was conducted at Pulses Research Sub-Station, Samba, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu during Rabi 2010-11 to find out effect of post-emergence (POE) herbicide imazathypr along with cultural weed control and weedy check on yield, yield attributes of chickpea under rainfed conditions. Twelve treatments consisting of three doses of the POE herbicide (Imazathypr) at 3 different durations (10, 20 & 30 days after germination-DAG) along with weedy check (control), hand weeding and weed free treatment were tested in randomized block design. The results revealed that significant reduction in total weed density and weed biomass were observed in treatments viz. two hand weedings (25-30 and 50-55 DAG) and imazathypr @ 20 g ha-1 at 30 DAG which in turn were at par but superior than weedy check treatment and hence resulted in significant improvement in yield attributing characters viz. no. of pods plant-1, no. of seeds pod-1, seed index, dry-weight plant-1 and seed yield than the other treatment combinations and weedy check treatment during the period under study. The yield and yield attributes were highly negatively correlated with weed infestation.
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ISLAM, A. K. M. Mominul, Fahima Sultana Popy, Ahmed Khairul Hasan i Md Parvez Anwar. "E Efficacy and Economics of Herbicidal Weed Management in Monsoon Rice of Bangladesh". Journal of Scientific Agriculture 1 (17.11.2017): 275. http://dx.doi.org/10.25081/jsa.2017.v1.834.
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Weed management is a challenging task in sustainable rice production. Physical and cultural methods of weed control are laborious and expensive, whereas chemical control is cheaper and less time consuming despite of some detrimental effect on environment with its inappropriate application. Considering these points, an experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh, Bangladesh during July–December 2015 to find out appropriate weed management practices for inbred and hybrid rice. The experiment comprised of four rice varieties (two inbred; BRRI dhan49 and Binadhan-7, and two hybrids; Dhani gold and Agrodhan-12); and eight herbicidal weed control treatments (season-long weedy or weed free, Pretilachlor fb Penoxsolum or 2,4-D dimethyl amine, Pendimethalin fb Penoxsolum or 2,4-D dimethyl amine, Pretilachlor or Pendimethalin fb one-time hand weeding). Eleven weed species belonging to five families were observed in the experimental plots. The highest weed density and dry weight were found in season-long weedy treatment and the lowest one was found in Pretilachlor fb one-time hand weeding. The highest above ground crop biomass (9.7 t ha-1) and harvest index (46.3%) were obtained from the hybrid variety Agrodhan-12 and the lowest biomass (8.3 t ha-1) was obtained from the inbred variety Binadhan-7. Season long weed free condition resulted the highest above ground crop biomass (10.9 t ha-1), harvest index (48.7%), highest yield increase over control (213.8), weed control efficiency (100%) and gross return (BDT 141480 ha-1) and the lowest values for all those parameters were obtained from season-long weedy treatment. Season-long weed free treatment combined with Pretilachlor or Pendimethalin fb one-time hand weeding showed the best performance in reducing weed density and increasing above ground crop biomass, but gross return was higher because of high labour wages in these treatments. The highest BCR (2.5) was observed in Pretilachlor fb Penoxsolum. Therefore from economic view point Pretilachlor fb Penoxsolum is the best combination. But from sustainability view point Pretilachlor or Pendimethalin along with one-time hand weeding may be recommended for effective weed management in inbred and hybrid rice during monsoon season.
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Jordan, N., i S. Huerd. "Effects of soil fungi on weed communities in a corn–soybean rotation". Renewable Agriculture and Food Systems 23, nr 2 (27.05.2008): 108–17. http://dx.doi.org/10.1017/s1742170508002226.
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AbstractIn a variety of ecosystems, interactions between soil microbiota and weedy plants can strongly affect population and community dynamics of these plants. However, weed–soil microbe interactions are not well characterized in field-crop agroecosystems. In Minnesota (USA), we repeatedly applied a fungicide (benomyl) to field plots in a corn–soybean crop rotation in each of 3 years, and sowed experimental weed communities containing host species for arbuscular-mycorrhizal fungi (AMF) and non-host species. Benomyl typically suppresses formation of mycorrhizal symbiosis in AMF-host plant species, and may also affect other soil fungi. We assessed weed density and biomass production, and monitored AMF colonization rates in each of 3 years. We found that weed density, biomass, community composition and the relative performance of AMF-host and non-host weed species were all significantly responsive to fungicide applications, although for all attributes responsiveness was variable. Fungicide application increased total weed density and biomass production in nearly all cases; most effects were modest but reached a maximum of 49%. Fungicide application also increased the relative performance of non-host species in most cases, although most effects were again modest. Our findings are the first assessment of responses by field-crop weeds to direct manipulation of soil microbial communities in a field setting, and suggest that the population and community ecology of these weeds can be strongly affected by the fungal component of soil microbiota.
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GUPTA, VARSHA, DEEP SINGH SASODE, EKTA JOSHI i Y. K. SINGH. "Response of non-chemical approaches of weed management in potato (Solanum tuberosum) crop under organic cultivation mode". Indian Journal of Agricultural Sciences 90, nr 11 (16.12.2020): 2076–82. http://dx.doi.org/10.56093/ijas.v90i11.108563.
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A field experiment was conducted during 2016-17 and 2017-18 at Gwalior, Madhya Pradesh, to study the effect of integrated weed management on weed species, yield and economics of potato (Solanum tuberosum L.) grown under chemical and non-chemical approaches of weed management. The treatments were white plastic mulch, black plastic mulch, straw mulching 5 t/ha (5 DAP), hand weeding (20 DAP) + straw mulching (25 DAP), two hand weedings (20 and 40 DAP), hand hoeing (20 DAP), hand hoeing (20 DAP) + hand weeding (40 DAP), metribuzin 500g/ha alone, metribuzin 500g/ha followed by hand weeding (40 DAP) and weedy check. Based on results, twice hand weeding deceased the weed density up to 86%, however one hand weeding with straw mulching 75%. At harvest, weed biomass under white and black plastic mulch compared to the weed infested treatment had highest around 46% in both but the lowest was observed where twice hand weeding was applied (19.20%) compared to weedy check. It can be concluded that twice hand weeding (20 and 40 DAP) resulted in better control of weeds with 78% WCE and maximum tuber yield (27.32 t/ha) followed by one hand weeding (20 DAP) + straw mulching (25 DAP) with 76% WCE and tuber yield 25.39 t/ha.
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Singh, Manoj K., i Swaran S. Saini. "Planting Date, Mulch, and Herbicide Rate Effects on the Growth, Yield, and Physicochemical Properties of Menthol Mint (Mentha Arvensis)". Weed Technology 22, nr 4 (grudzień 2008): 691–98. http://dx.doi.org/10.1614/wt-08-027.1.
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Field experiments were conducted in 2001 and 2002 to study the effect of date of planting, herbicide, and straw mulch on menthol mint yield and oil quality in northwest India. Menthol mint was planted at three dates (December 10, December 30, and January 20). Diuron was applied prior to emergence at rates of 0.0, 0.4, and 0.6 kg ai/ha, with and without rice straw mulch (6 t/ha). Menthol mint planted on December 30 and January 20 produced more plantlets and dry matter than the December 10 planting. Menthol mint planted on December 10 had higher weed density and weed biomass, and lower menthol mint herbage and oil yield than the later planting dates. Straw mulch application reduced weed density and weed biomass, and increased plantlet population, menthol mint dry matter accumulation, fresh herbage, and menthol mint oil yield. Preemergence (PRE) applications of diuron at 0.4 and 0.6 kg ai/ha increased menthol mint population and crop dry matter accumulation, and decreased weed density and weed biomass compared to the weedy check. Diuron at 0.6 kg/ha increased fresh herbage and menthol mint oil yield over the untreated weedy check, but there were no other differences between the two rates of diuron. Physicochemical properties of menthol mint oil were not affected by any of the three tested factors.
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Puka-Beals, Jesse, i Greta Gramig. "Weed Suppression Potential of Living Mulches, Newspaper Hydromulches, and Compost Blankets in Organically Managed Carrot Production". HortTechnology 31, nr 1 (luty 2021): 89–96. http://dx.doi.org/10.21273/horttech04745-20.
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Direct seeding into strip-tilled zones (STZs) of living mulches may require weed suppression tactics for soil surfaces exposed within the STZ. Three surface mulch options (hydromulch, compost blanket, and a no-mulch control) were evaluated for their ability to suppress weeds and improve crop performance when applied in STZs seeded to carrot (Daucus carota). These STZs were located within one of five living mulch options [red clover (Trifolium pratense), white clover (Trifolium repens), perennial ryegrass (Lolium perenne), a weed-free control, and a weedy control]. From measurements spanning 2 years at two North Dakota locations, dry weed biomass was lower in STZs where hydromulch or compost blankets were applied compared with the no-mulch control (12, 13, and 82 g·m−2, respectively). The presence of a living mulch adjacent to the STZ reduced carrot root biomass by 49% to 84% compared with the weed-free control. Further research should 1) investigate methods for reducing yield loss from living mulches, and 2) develop biodegradable alternatives to plastic mulches.
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Zandvakili, Omid R., Masoud Hashemi, Mohammad R. Chaichi, Allen V. Barker, Reza Keshavarz Afshar, Hamid R. Mashhadi, Mostafa Oveysi i Maryam Sabet. "Role of cover crops and nicosulfuron dosage on weed control and productivity in corn crop". Weed Science 68, nr 6 (18.09.2020): 664–72. http://dx.doi.org/10.1017/wsc.2020.71.
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AbstractA field experiment was conducted at the research farm of the University of Tehran to evaluate the effect of cover crops and herbicide (nicosulfuron) dosage on corn (Zea mays L.) productivity. Cover crops suppressed weed biomass and density during the fallow period; however, there was no significant effect on weed biomass or weed density in the subsequent corn crop. A mixture of cereal rye (Secale cereale L.) and hairy vetch (Vicia villosa Roth.) was the most weed-suppressive cover in the fallow period. Nicosulfuron applied at different amounts suppressed weed biomass and density in corn when compared with weedy plots. Application of 40 g ai ha−1 of nicosulfuron was as effective on weed control as the recommended application. Cover crops did not affect corn growth; however, corn yield improved with herbicide application.
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Bijanzadeh, Ehsan, i Hossein Ghadiri. "Effect of Separate and Combined Treatments of Herbicides on Weed Control and Corn (Zea mays) Yield". Weed Technology 20, nr 3 (wrzesień 2006): 640–45. http://dx.doi.org/10.1614/wt-05-105r1.1.
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Field studies were conducted at Shiraz, Iran, during 2000 and 2001 to investigate the effect of separate and combined herbicide treatments on weed control and corn yield. Separate and combined herbicide treatments included 14 combinations applied at two rates. Herbicides reduced weed biomass compared with the weedy check. In both years, maximum reduction in weed biomass was observed with atrazine plus alachlor at 1 + 2.44 and 1.5 + 1.92 kg ai/ha and minimum reduction in weed biomass was observed with rimsulfuron at 0.02 and 0.04 kg/ha. In 2000 and 2001, 2,4-D plus MCPA at 0.36 + 0.31 and 0.54 + 0.46 kg/ha, and alachlor plus 2,4-D plus MCPA at 1.92 + 0.54 + 0.46 kg/ha, and 2.44 + 0.36 + 0.31 kg/ha, controlled 80 to 100% of field bindweed and rimsulfuron at 0.02 and 0.04 kg/ha controlled 17 to 70% of field bindweed. All herbicide treatments controlled redroot pigweed 60 to 100%. In 2000, at 6 and 17 WAP, minimum biomass reduction of Chinese-lantern-plant was observed with 2,4-D plus MCPA at 0.36 + 0.31 and 0.54 + 0.46 kg/ha, and primisulfuron plus prosulfuron at 0.02 + 0.02 and 0.03 + 0.03 kg/ha. Rimsulfuron plus primisulfuron plus prosulfuron at 0.02 + 0.03 + 0.03 and 0.04 + 0.02 + 0.02 kg/ha reduced johnsongrass biomass 96 to 100% and the efficacy of rimsulfuron increased when tank mixed with primisulfuron plus prosulfuron. Results of both years showed that all herbicide treatments increased corn grain yield as compared with the weedy check. Maximum corn grain yield was obtained with combinations of atrazine plus alachlor at 1 + 2.44 and 1.5 + 1.92 kg/ha.
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Gustafson, Travis C., Stevan Z. Knezevic, Thomas E. Hunt i John L. Lindquist. "Simulated insect defoliation and duration of weed interference affected soybean growth". Weed Science 54, nr 4 (sierpień 2006): 735–42. http://dx.doi.org/10.1614/ws-06-014r.1.
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An improved understanding of crop stress from multiple pests is needed for better implementation of integrated pest management (IPM) strategies. Field studies were conducted in 2003 and 2004 at two locations in eastern Nebraska to describe the effects of simulated early-season insect defoliation of soybean and duration of weed interference on soybean growth. Three levels of simulated defoliation (undefoliated, 30, and 60%) and seven durations of weed interference (weedy and weed free; weed removal at V2, V4, V6, R3, and R5) were evaluated in a split-plot design. Defoliation significantly reduced soybean leaf-area index (LAI), total dry matter (TDM), and crop height in season-long weedy treatments only. Biomass partitioning during vegetative and reproductive growth was affected by both defoliation and weed interference. Increase in soybean relative growth rate (RGR) and biomass production soon after defoliation occurred (e.g., V5 stage) indicated potential defense mechanism by which soybean is able to adjust its physiology in response to the loss of leaf area. Weed interference combined with defoliation caused the greatest yield losses up to 97%. Results from this study indicate the need for monitoring early-season insect density and weed growth to determine if simultaneous control of both pests may be needed.
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Khan, Bilal Ahmad. "COMPARATIVE EFFICACY OF DIFFERENT HERBICIDES FOR WEED MANAGEMENT IN LENTIL (Lens culinaris L.)". JOURNAL OF WEED SCIENCE RESEARCH 28, nr 3 (31.03.2022): 29–44. http://dx.doi.org/10.28941/pjwsr.v28i1.994.
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Weeds are a major threat to global crop productivity and food security. Weeds compete with plants for applied inputs and resources and resultant cause a significant reduction in final productivity. A study was conducted at Agronomic Research Area, University of Agriculture, Faisalabad. The study was comprised of two lentil varieties (Punjab Masoor-2009, Punjab Masoor-2020) and seven treatments i.e., weedy check (control), manual weeding, Pendimethalin 33 EC @ 247 ml ha-1, S. metolachlor 960 EC @ 1976 ml ha-1, Pendimethalin +S. metolachlor @ 2223 ml ha-1, Flumetsulam 80 WG @ 18.525 g ha-1 and Flumetsulam 80 WG @ 24.7 g ha-1 arranged in RCBD design having 3 replications. According to the findings, different herbicides and cultivars had a substantial impact on growth and yield attributes of lentil. The maximum root fresh and dry weights (8.07, 1.57 g), shoot fresh and dry weights (20.08 and 5.28 g), plant height (62.05 cm), pods/plant (67.83), grains/pod (2), 1000 seed weight (25.17 g), grain yield (1934 kg ha-1) and biological yield (3730 kg ha-1) was recorded in manual weeding and lowest root fresh and dry weights (6.28 and 1.57 g), shoot fresh and dry weights (12.33 and 3.99 g), plant height (44.58 cm), pods/plant (42.83), grains/pod (1.17), 1000 seed weight (14.40 g), grain yield (1113 kg ha-1) and biological yield (2830 kg ha-1) was recorded in weedy check. In case of cultivars, Punjab Masoor-2020 had maximum root fresh and dry weights (7.90 and 1.81 g), shoot fresh and dry weights (17.17 and 5.02 g), plant height (54.99 cm), pods/plant (60.43), grains/pod (1.67), 1000 seed weight (21.09 g), grain yield (1690 kg ha-1) and biological yield (3402 kg ha-1) while cultivar Punjab Masoor-2009 had minimum root fresh weight (6.53 g), dry weight (1.68 g), shoot fresh weight (14.57), dry weight (4.62 g), plant height (53.09 cm), pods/plant (48.76), grains/pod (1.33), 1000 seed weight (18.44 g), grain yield (1586 kg ha-1) and biological yield (3292 kg ha-1). Manual weeding also resulted in lowest weeds density and weeds biomass and weedy check resulted in maximum weed density and weed biomass. Thus, it is concluded that cultivar Punjab Masoor-2020 along with manual weeding and use of Pendimethalin + S. metolachlor @ 2223 ml ha-1 can be adopted to get maximum lentil production under warm semi-arid conditions of Faisalabad.
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Tarrant, Alyssa R., Daniel C. Brainard i Zachary D. Hayden. "Cover Crop Performance between Plastic-mulched Beds: Impacts on Weeds and Soil Resources". HortScience 55, nr 7 (lipiec 2020): 1069–77. http://dx.doi.org/10.21273/hortsci14956-20.
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Growing a cover crop living mulch between plastic-mulched beds may reduce soil erosion while providing other agroecosystem services. However, information regarding the relative differences among living mulch species to maximize services and minimize competition for nutrients and water in adjacent plastic-mulched beds is limited. A 2-year experiment in Michigan evaluated nine living mulch species for biomass production, in-season weed suppression, and potential for cash crop competition. Species included three warm season grasses {Italian ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot], teff [Eragrostis tef (Zuccagni) Trotter, and sudangrass [Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan]}; three cool season grasses [barley (Hordeum vulgare L.), rye (Secale cereale L.), and wheat (Triticum aestivum L.)]; and three clover species grown in combination with rye {Dutch white clover (Trifolium repens L.), New Zealand white clover (T. repens L.) and yellow blossom sweet clover [Melilotus officinalis (L.) Lam.]}. Although all living mulch treatments significantly reduced in-season weed biomass relative to the weedy control in 2018, weeds were generally a dominant component of total biomass in all living mulch treatments other than teff. Weed biomass was negatively correlated with living mulch biomass, and teff exhibited both the greatest biomass and weed suppression in both years. However, despite spatial and physical separation, all living mulches demonstrated the potential to compete with a cash crop by reducing soil inorganic nitrogen and moisture levels in adjacent plastic mulch–covered beds. Growers interested in integrating living mulches into plasticulture systems must consider desired benefits such as enhanced weed suppression, soil quality, and harvesting conditions alongside potential risks to cash crop yields.
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Blackshaw, Robert E. "Safflower (Carthamus tinctorius) Density and Row Spacing Effects on Competition with Green Foxtail (Setaria viridis)". Weed Science 41, nr 3 (wrzesień 1993): 403–8. http://dx.doi.org/10.1017/s0043174500052115.
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Field experiments were conducted in 1990 and 1991 at Lethbridge, Alberta, to determine if narrower row spacings and increased plant densities than commonly practiced would improve safflower's competitive ability with weeds. A factorial set of treatments of safflower at two row spacings of 11 and 22 cm and six densities ranging from 10 to 192 plants m−2grown weed free or infested with green foxtail (Setaria viridis(L.) Beauv.). Decreasing safflower row spacing from 22 to 11 cm slightly improved competition with green foxtail, but increasing safflower density had a much greater effect. Weed-free safflower biomass and seed yield plateaued at 70 and 84 plants m−2in 1990 and 1991, respectively. However, safflower infested with 500 plants m−2of green foxtail increased in biomass and seed production up to 100 plants m−2in 1990 and 156 plants m−2in 1991. At these high densities, weedy safflower yielded less than weed-free safflower but three to four times more than achieved at lower stand densities. Concurrently, high safflower density reduced green foxtail biomass up to 72% and seed yield up to 85%. Dense safflower stands developed a closed canopy early in the season and shaded green foxtail more than thin stands.
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Burnside, Orvin C., Melvin J. Wiens, Bobby J. Holder, Sanford Weisbere, Eric A. Ristau, Michelle M. Johnson i James H. Cameron. "Critical periods for weed control in dry beans (Phaseolus vulgaris)". Weed Science 46, nr 3 (czerwiec 1998): 301–6. http://dx.doi.org/10.1017/s0043174500089451.
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Weed removal experiments in dry edible beans were conducted during 1992 and 1993 at Crookston and Staples, MN. Ten manual weed removal treatments were studied to determine when a natural infestation of weeds first reduced dry bean yield, and when weed removal could be discontinued without further loss of seed yield. Major weeds in order of average biomass production on weedy check plots at dry bean harvest over locations and years were wild mustard, foxtail spp., redroot pigweed, common ragweed, wild buckwheat, hairy nightshade, and common lambsquarters. Hairy nightshade also emerged late in the growing season and could negatively affect harvest efficiency and stain navy beans. Weed removal treatments had little effect on dry bean stands or 100-seed weights of harvested dry bean seed. The critical period for weed control in dry beans was 3 to 5 or 6 weeks after planting (WAP). Thus, weed control practices should begin no later than 3 WAP and continue until at least 5 or 6 WAP for maximum dry bean yields.
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Spasojevic, Igor, Vesna Dragicevic, Milena Simic, Dusan Kovacevic i Milan Brankov. "Effects of different cropping systems and weed management methods on free energy and content of pigments in maize". Pesticidi i fitomedicina 29, nr 1 (2014): 45–54. http://dx.doi.org/10.2298/pif1401045s.
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Rotation is a cropping system that has many advantages and ensures better crop growth and yielding. Its combinination with other cropping measures can ensure optimal crop density for maximal growth and photosynthesis efficiency. The aim of this study was to investigate the influence of different cropping systems: monoculture and two rotations, including maize, wheat and soybean (MSW and MWS), and different weed management methods (weed removal by hoeing, application of a full recommended herbicide dose (RD) and half that dose (0.5 RD), and weedy check) on weed biomass and maize growth parameters - leaf area index (LAI), free energy, contents of chlorophyll and carotenoids, grain yield, and their possible relationships in two fields of the maize hybrids ZP 677 (H1) and ZP 606 (H2). The lowest LAI and grain yield were found in monoculture, particularly in weedy check, which had relatively high weed infestation. Higher weed biomass was also observed in herbicide treated plots in monoculture. Such high competition pressure indicates a stress reflected on reduced LAI and chlorophyll content, and increased free energy and content of carotenoids. On the other hand, rotation, particularly if it is combined with the application of herbicides or hoeing, had a positive impact on yielding potential by increasing LAI and the contents of chlorophyll and carotenoids, and decreasing free energy.