Journal articles on the topic 'Density of irrigation'
To see the other types of publications on this topic, follow the link: Density of irrigation.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Density of irrigation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Schutte, Brian J., Nina Klypin, and Manoj K. Shukla. "Influence of Irrigation Timing on Disturbance-Induced Reductions in Soil Seedbank Density." Weed Science 64, no. 4 (December 2016): 613–23. http://dx.doi.org/10.1614/ws-d-15-00191.1.
Full textAbstract:
Studies suggest that disturbance-induced reductions in soil seedbank density are diminished by periods of water scarcity after soil disturbance; however, this hypothesis has yet to be tested. The objectives of this study were (1) to determine the effects of increasing time between soil disturbance and flood irrigation on disturbance-induced reductions in soil seedbank density, and (2) to identify specific soil moisture levels that cause seedbank reductions under flood irrigation. Weed species in this study were junglerice, Palmer amaranth, and yellow foxtail. For Objective 1, artificial seedbanks with known numbers of seeds were disturbed 10, 3, or 0 d prior to flood irrigations under field conditions. For Objective 2, seeds were buried in soil mesocosms that were hydrated to specific soil water potentials (flooded, 0 kPa, −30 kPa, −60 kPa, and −180 kPa) and placed in laboratory conditions favorable for germination. For both objectives, seeds were recovered to determine the percentages of buried seeds that survived the disturbance or moisture treatments. Results for the field study indicated that soil disturbances reduced seedbank persistence of Palmer amaranth but did not affect seedbank persistence of junglerice and yellow foxtail. Disturbance-induced reductions in seedbank density were greatest when soil was disturbed 0 and 3 d prior to flood irrigations. For the laboratory study, results showed that waterlogged soil was not required for seedbank losses because rates of seedbank persistence were greater in saturated soils (0 kPa and flooded) compared to the lower moisture levels. These studies indicate that delays in irrigation can reduce the seedbank reduction potentials of soil disturbance events. Further, irrigation timing effects on disturbed soil seedbanks are likely to occur in all irrigation systems, including those that reduce the amount of water applied compared to flood irrigation.
2
Arbizu-Milagro, Julia, Francisco J. Castillo-Ruiz, Alberto Tascón, and Jose M. Peña. "How Could Precision Irrigation Based on Daily Trunk Growth Improve Super High-Density Olive Orchard Irrigation Efficiency?" Agronomy 12, no. 4 (March 22, 2022): 756. http://dx.doi.org/10.3390/agronomy12040756.
Full textAbstract:
Water deficit, especially during summer, is currently one of the most important stress factors that influence olive oil production in olive orchards. A precision irrigation strategy, based on daily trunk growth, was assessed and compared with one continuous deficit, one full irrigation, and two different regulated deficit irrigation strategies. All of them were tested in a super high-density olive orchard located in northeast Spain, in which oil production, main oil production components, applied irrigation water, and water productivity were assessed. For this purpose, the crop was monitored from budding to harvesting, mainly during the summer months in which the Precision strategy only applied water after two days of negative daily trunk growth. Maximum monthly water savings for the Precision strategy reached 91.8%, compared with full irrigation, while major annual mean water savings reached 50% for the continuous deficit strategy and 31.2% for the Precision strategy, which also reduced irrigation events by up to 19.7%, compared with the full irrigation strategy. Oil production and oil production components varied depending on the irrigation strategies providing the Control, one of the regulated deficit irrigations, and Precision higher values than the other strategies; oil yield results differ, nonetheless. The Precision strategy showed an overall better performance. Despite this, it did not achieve the highest water saving, it achieved higher water productivity.
3
BROWN, D. M. "CORN YIELD RESPONSE TO IRRIGATION, PLANT POPULATION AND NITROGEN IN A COOL, HUMID CLIMATE." Canadian Journal of Plant Science 66, no. 3 (July 1, 1986): 453–64. http://dx.doi.org/10.4141/cjps86-063.
Full textAbstract:
Summer dry spells in some areas of southern Ontario during the last decade have increased interest in supplemental irrigation. Field studies were conducted in a 2500 heat unit area of southern Ontario on Orthic/Brunisolic Grey Brown Luvisol soils to determine the yield response of field corn (Zea mays L.) to irrigation in midsummer when combined with increased plant density and N rates. The yield responses, phenological records and soil moisture measurements are to be used in the calibration and validation of a corn yield estimation model, to be published in a subsequent paper. Two to four irrigations were applied each year using the line method when soil moisture pressure potential reached −40 to −60 kPa at 22.5 cm depth. Development stages were unaffected by irrigation. Yield increases from irrigation were directly proportional to water applied in midsummer and the intensity of dry weather. Yields increased with plant density in 4 of the 5 yr and were usually consistent over irrigation levels. Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years. In years of positive response to extra nitrogen, there was usually a greater response with irrigation and the responses were greatest at high plant density and for the longer season hybrids. Harvest indices decreased as irrigation amount increased and were exceptionally high in 1983.Key words: Corn, Zea mays L., line-source irrigation, plant population, nitrogen, harvest index
4
Kałużewicz, Alina, Jolanta Lisiecka, Monika Gąsecka, Włodzimierz Krzesiński, Tomasz Spiżewski, Anna Zaworska, and Barbara Frąszczak. "The effects of plant density and irrigation on phenolic content in cauliflower." Horticultural Science 44, No. 4 (November 13, 2017): 178–85. http://dx.doi.org/10.17221/60/2016-hortsci.
Full textAbstract:
This study was conducted to study the influence of plant density and irrigation on the content of phenolic compounds, i.e., phenolic acids and flavonols in cv. ‘Sevilla’ cauliflower curds. Levels of phenolic acids and flavonols were in the range of 3.0–6.2 mg and 25.4–87.8 mg/100 g of dry weight, respectively, depending on plant density and irrigation. Of the phenolic acids, caffeic acid was detected in the highest amount, followed by p-coumaric acid, sinapic acid, gallic acid, and ferulic acid. Of the two flavonols detected, the levels of quercetin were higher than those of kaempferol. The content of the detected phenolic acids (with the exception of ferulic acid) and both flavonols increased with increasing plant density. Furthermore, the concentration of phenolic compounds (with the exception of ferulic acid) was significantly higher under irrigation.
5
Qi, Xue Bin, Zong Dong Huang, Dong Mei Qiao, Ping Li, Zhi Juan Zhao, Tao Fan, Hai Qing Wu, et al. "Effect of New Irrigation Technology on the Physiology and Water Use Efficiency of Potato by Reclaimed Water Irrigation." Advanced Materials Research 726-731 (August 2013): 3035–39. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.3035.
Full textAbstract:
Agriculture is a big consumer of fresh water in competition with other sectors of the society. The agricultural sector continues to have a negative impact on the ecological status of the environment. The worlds interest in high quality food is increasing. Field experiments were conducted to investigate the effect of subsurface drip irrigation on physiological responses, yield and water use efficiency, Soil nitrogen, Root weight density of potato in the semi-humid region of middle China using subsurface drip irrigation. The experiment used second-stage treated wastewater with and without addition of chloride, and both subsurface drip and furrow irrigations were investigated. Results indicated that the alternate partial root-zone irrigation is a practicable water-saving strategy for potato. The drip with chlorinated and non-chlorinated water improved water use efficiency by 21.48% and 39.1%, respectively, and 44.1% in the furrow irrigation. Partial root zone drying irrigation stimulates potato root growth and enhances root density. The content of the heavy metal in the potato tubers is no more than the National Food Requirements, and it is consistent with National Food Hygiene Stands.
6
Rathore, J. P., Pawan K. Nagar, Amit Kumar, Anil Sharma, Kalpana Choudhary, and Manish Kumar Meena. "DRIP IRRIGATION SYSTEM IS BEST IRRIGATION SYSTEM UNDER HIGH DENSITY ORCHARDS." International Journal of Engineering Applied Sciences and Technology 04, no. 06 (December 1, 2019): 182–86. http://dx.doi.org/10.33564/ijeast.2019.v04i06.031.
Full text
7
Mundy, G. N., K. J. Nexhip, N. R. Austin, and M. D. Collins. "The influence of cutting and grazing on phosphorus and nitrogen in irrigation runoff from perennial pasture." Soil Research 41, no. 4 (2003): 675. http://dx.doi.org/10.1071/sr02087.
Full textAbstract:
Runoff from flood-irrigated perennial pastures generally contains higher phosphorus (P) and nitrogen (N) concentrations than the irrigation water applied to the pastures. We examined the sources of P and N that could contribute to these elevated nutrient concentrations in runoff.The first experiment compared P and N losses in runoff from pasture cut to different residual pasture masses. Flow-weighted P and N concentrations and loads were about 100% higher from pasture cut to 47�mm above ground than from pasture standing at 155 mm. These results indicated that severely defoliated pasture may be a significant source of nutrients when flood irrigated.In the second experiment, pastures were defoliated at a single grazing with different stocking intensities and the flow-weighted P and N concentrations in runoff were determined during 4 successive flood irrigation events. Nitrogen and P concentrations in runoff after the first irrigation following defoliation were higher at the highest stocking intensity. However, the effect of the grazing on nutrient concentrations in runoff declined in subsequent irrigation events. A regression model fitted to the P data indicated that there was a significant linear increase in P concentrations with stocking density and a significant non-linear decline in concentrations with successive irrigations. A similar relationship for TKN concentrations in runoff at each stocking density over the 4 irrigation events was not found. An inconsistency of the TKN concentrations of the supply water between irrigation events possibly helped to mask a similar relationship between N concentrations in runoff and stocking density over the 4 irrigation events. We postulate that both animal excreta and the pasture itself can contribute to elevated nutrient concentrations in flood-irrigation runoff.
8
Aydin Veliyeva, Mahira. "INFLUENCE OF PLANT DENSITY ON PRODUCTIVINESS AND CORRELATION BETWEEN PRODUCTIVITY ELEMENTS." NATURE AND SCIENCE 03, no. 04 (October 27, 2020): 14–25. http://dx.doi.org/10.36719/2707-1146/04/14-25.
Full textAbstract:
The article is devoted to the introduction of the “Studying of the effect of external conditions and components of agro-technical cultivation components on falling degree of vegetative organs of cotton plant” which was started in 2011, where the plant density is also described. The experiment was carried out in the plots with 100m length, 4- rowed fields by 4 repeats and 12 options. The size of each of the rows was 240 m2, total experimental plot equaled 240 x 12 x 4=11520m2. By that purpose observation over plant densities had been conducted in the experiments which were based on introduction of microelements at two periods, on background of fertilizers N100 P100 K50, two plant densities and three deeply varying irrigation regimes. The factors affecting on decline at 6020x1; 60x20x2 plant density, dependence between plant density and mass of a ball, plant density and productiveness are determined. Key words:plant density, water-nutrition, irrigation regime, hard, optimal, high regime of irrigation, nutrition area, fruit organs, falling, correlation.
9
Culpepper, A. Stanley, Timothy L. Grey, and Theodore M. Webster. "Vegetable Response to Herbicides Applied to Low-Density Polyethylene Mulch Prior to Transplant." Weed Technology 23, no. 3 (September 2009): 444–49. http://dx.doi.org/10.1614/wt-08-135.1.
Full textAbstract:
Few herbicides are available for weed control in vegetable production systems using low-density polyethylene (LDPE) plastic mulch. With the elimination of methyl bromide for pest management and subsequent use of various alternative fumigants, the need for herbicides in vegetable production systems has increased. An experiment was conducted to evaluate tolerance of transplant summer squash and tomato to carfentrazone, flumioxazin, glyphosate, halosulfuron, or paraquat applied to the mulch prior to transplanting. After applying herbicides overtop of the mulch but prior to vegetable transplant, the mulch was either irrigated with 1.0 cm of water or not irrigated. Carfentrazone did not affect either crop regardless of irrigation. Irrigation readily removed glyphosate and paraquat from the mulch, as there was no adverse crop injury in these treatments. In the absence of irrigation, glyphosate and paraquat reduced squash diameter and tomato heights 18 to 34% at 3 wk after transplanting (WAT). Squash and tomato fruit numbers and fruit biomass (yield) were reduced 17 to 37%, and 25 to 33%, respectively. Halosulfuron reduced squash diameter and yield 71 to 74% and tomato heights and yields 16 to 37% when mulch was not irrigated prior to transplanting. After irrigating, halosulfuron had no affect on tomato, but reduced squash growth and yield 40 to 44%. Flumioxazin killed both crops when the mulch was not irrigated; and reduced squash yield 56% when irrigated. With irrigation, flumioxazin did not impact tomato fruit number, but did reduce tomato weight by 25%. These studies demonstrate the safety of carfentrazone, applied on mulch prior to transplanting either squash or tomato, regardless of irrigation, and also demonstrate the safety of glyphosate and paraquat if irrigated prior to transplanting. Conversely, flumioxazin should not be applied over mulch before transplanting either crop, regardless of irrigation. Halosulfuron application over mulch should be avoided before transplanting squash, regardless of irrigation, but can be applied prior to transplanting tomato if irrigated.
10
Jiang, Xiaohu, and Long He. "Investigation of Effective Irrigation Strategies for High-Density Apple Orchards in Pennsylvania." Agronomy 11, no. 4 (April 10, 2021): 732. http://dx.doi.org/10.3390/agronomy11040732.
Full textAbstract:
Irrigation helps grow agricultural crops in dry areas and during periods of inadequate rainfall. Proper irrigation could improve both crop productivity and produce quality. For high density apple orchards, water relations are even more important. Most irrigation in tree fruit orchards is applied based on grower’s experience or simple observations, which may lead to over- or under-irrigation. To investigate an effective irrigation strategy in high-density apple orchard, three irrigation methods were tested including soil moisture-based, evapotranspiration (ET)-based and conventional methods. In soil moisture-based irrigation, soil water content and soil water potential sensors were measured side by side. In ET-based irrigation, daily ET (ETc) and accumulated water deficit were calculated. Conventional method was based on the experience of the operator. The experiment was conducted from early June through middle of October (one growing season). Lastly, water consumption, fruit yield and fruit quality were analyzed for these irrigation strategies. Results indicated that the soil moisture-based irrigation used least water, with 10.8% and 4.8% less than ET-based and conventional methods, respectively. The yield from the rows with the soil moisture-based irrigation was slightly higher than the other two, while the fruit quality was similar. The outcome from this study proved the effectiveness of using soil moisture sensors for irrigation scheduling and could be an important step for future automatic irrigation system.
11
BURCEA, Mariana, Emil GEORGESCU, and Adina BURCEA. "Maximizing the Positive Impacts of Irrigation and Its Influence on the Settlement of Soil Particles." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Agriculture 70, no. 1 (November 26, 2013): 129–33. http://dx.doi.org/10.15835/buasvmcn-agr:9778.
Full textAbstract:
Researches presented, are the subject of study on the evolution of soil quality indicators of Romanian Plain, where mainly is chernozem soil type, as a consequence of irrigation. To achieve the objectives we have studied some physical indicators of soil ( bulk density and total porosity ) în the territory concerned, the interpretation of analytical results been performed according to the proper methodology, after taking soil samplings from pedogenetic horizons. Through an analysis of the evolution of chernozem’s soil compaction, due to irrigation’s application, it highlights different soil compaction status correlated with the physical condition of the soil. If irrigated soil, in maize crop, loosening is moderate în the layer 0-10 cm, with values of 1.20 g/cm3,after applying every year of irrigation, it indicates values ranging în a fairly widely, from small (moderately loose soil, with bulk density of 1.23 g/cm3) , the medium ( soil poorly compacted, bulk density was 1.45 g/cm3) . Total porosity values are down slightly throughout the soil profile under the influence of irrigation, values are în the range middle - very high. After applying irrigation are observed physical changes, that induced changes in the balances resulting from damage to structure and structure to appear grainy dust structure and consequently the tendency of poor compaction and physical change of the soil.
12
Grey, Timothy L., William K. Vencill, Theodore M. Webster, and A. Stanley Culpepper. "Herbicide Dissipation from Low Density Polyethylene Mulch." Weed Science 57, no. 3 (June 2009): 351–56. http://dx.doi.org/10.1614/ws-08-144.1.
Full textAbstract:
Field and laboratory studies were conducted to examine herbicide dissipation when applied to low density polyethylene (LDPE) mulch for dry scenarios vs. irrigation. Analytical chemical analysis was used for quantification. In field studies, halosulfuron, paraquat, carfentrazone, glyphosate, and flumioxazin were surface applied to black 32-μm-thick (1.25 mil) LDPE mulch. LDPE mulch harvest began 1 h after treatment (HAT) then continued every 24 h for five consecutive rain-free days after treatment (DAT) to determine the level of herbicide dissipation from the LDPE mulch surface. In a related study, treated LDPE mulch was harvested 1 HAT, then sprinkler irrigation was applied, followed by a sampling five HAT, then the same irrigation and sampling procedure was repeated every 24 h for five consecutive DAT. The order for half-life, as defined as time for 50% dissipation (DT50), varied by herbicide and method of dissipation for dry and irrigated studies. Data indicated that glyphosate and paraquat dissipation was rapid following irrigation. Glyphosate and paraquat DT50 were both 1 h in the irrigated study, but 84 and 32 h for the dry scenario, respectively. This indicated that glyphosate and paraquat could be removed from LDPE mulch with rainfall or irrigation, primarily due to their high water solubility. Halosulfuron and flumioxazin DT50 were 3 and 6 h in the irrigated study, and 18 and 57 h for the dry study, respectively. Carfentrazone DT50 was similar at 28 and 30 h for the irrigated and dry studies, respectively. This indicated that carfentrazone was adsorbed to the LDPE mulch, and irrigation water did not remove it from the LDPE mulch. Results from 14C-herbicide laboratory studies were similar to those from field studies for halosulfuron, glyphosate, paraquat, and flumioxazin.
13
Awe, Gabriel Oladele, Busola Margret Ayuba, Japheth Umam, and Toyin Peter Abegunrin. "Short-Term Impact of Drip Irrigation Frequency on Soil Hydro-Physical Properties of an Alfisol and Performance of Two Maize Varieties." Turkish Journal of Agriculture - Food Science and Technology 8, no. 8 (August 30, 2020): 1675–85. http://dx.doi.org/10.24925/turjaf.v8i8.1675-1685.3453.
Full textAbstract:
Irrigation scheduling is important for efficient use of applied water and for maximizing crop yields. Therefore, the aim of this study was to evaluate the short-term effect of drip irrigation frequency on soil hydro-physical properties of an Alfisol and performance of two maize varieties, at the Teaching and Research Farm, Faculty of Agricultural Sciences, Ekiti State University, Ado Ekiti, Southwest Nigeria. The experiment was laid out using a split-plot experiment in randomized complete block design (RCBD) and three replications. Irrigation frequency constituted the main plot namely: irrigation four times a week (I4), irrigation thrice a week (I3), and irrigation twice a week (I2) of re-filling soil to field capacity while the subplot was maize variety namely: V1: SAMMAZ-27 and V2: OBA-super-6. Plant growth parameters and soil physical properties of soil water content (SWC), bulk density (BD) and saturated hydraulic conductivity (Ksat) were monitored during the growing cycle. Water use efficiency (WUE) and yield components were determined at maturity. There were significant interactions between irrigation regime and maize variety on SWC and Ksat. The maximum bulk density (BDmax) and optimum soil water content SWCopt were 1.41 g/cm3 and 0.12 g/g, respectively. Plant height (PH) did not differ between the two maize varieties throughout the growth cycle. Drip irrigation frequency did not significantly affect plant height until growth stage V12 (12 fully opened leaves), with I4 irrigation treatment having the tallest plant. Both drip irrigation and maize variety had no significant influence on both LAI and CC, neither was there any significant interaction effect. Increasing irrigation water increased maize yield and yield components. The treatment combination of I4V1 had the highest performance indices in terms of yield components. WUE decreased with increasing frequency of irrigation water application while the WUE of SAMMAZ-27 > OBA-super-6. Therefore, irrigating four times a week and SAMAZ-27 maize variety could be a suitable irrigation-variety combination for providing sustainable irrigation agriculture for maize in this region.
14
A. J. Schlegel, L. R. Stone, T. J. Dumler, and F. R. Lamm. "Managing Diminished Irrigation Capacity with Preseason Irrigation and Plant Density for Corn Production." Transactions of the ASABE 55, no. 2 (2012): 525–31. http://dx.doi.org/10.13031/2013.41394.
Full text
15
Mojid, MA, and ABM Zahid Hossain. "Conjunctive Use of Saline and Fresh Water for Irrigating Wheat (Triticum aestivum L.) at Different Growth Stages." Agriculturists 11, no. 1 (June 10, 2013): 15–23. http://dx.doi.org/10.3329/agric.v11i1.15237.
Full textAbstract:
An experiment was conducted at the Bangladesh Agricultural University, Mymensingh during 2008 2009 and 20092010 to investigate the impacts of irrigation by saline water (7 dS m-1) at different growth stages of wheat (Triticum aestivum L.). Irrigations at crown root initiation (CRI) (T1) or booting (T2) or flowering (T3) or grain filling (T4) stage by saline water but at other growth stages by fresh water, and irrigation at all growth stages by fresh water (T5, control) were applied. Wheat was cultivated in two consecutive years (2008 2010) under four irrigations and with recommended fertilizer doses. Irrigation water having salinity of 7 dS m-1 did not significantly influence plant height, spike density, spikelets per spike, 1000-grain weight, grain yield, biomass yield and harvest index. The observed diminutive variations among the treatments reflected only non harmful impacts of salinity. Irrigation water salinity, however, significantly reduced spike length and grains per spike in most cases in the first year only. Treatment T4 producing, on an average over two years, the lowest grain yield (30% less compared to T5), grains per spike, spike length and spikelets per spike revealed that the grain filling stage of wheat was the most sensitive to irrigation water salinity. Although application of one of four irrigations by water of salinity 7 dS m-1 did not impart significant effect on wheat production, it was beneficial to avoid such irrigation at the grain filling stage. DOI: http://dx.doi.org/10.3329/agric.v11i1.15237 The Agriculturists 2013; 11(1) 15-23
16
Ferré, Chiara, Gaia Mascetti, and Roberto Comolli. "High-Density Poplar SRC Accumulates More Soil Organic Carbon Than Very-High-Density SRC." Agronomy 11, no. 3 (March 19, 2021): 584. http://dx.doi.org/10.3390/agronomy11030584.
Full textAbstract:
Short rotation coppice (SRC) systems play an important role in producing renewable energy and contributing to soil organic carbon storage while providing potential mitigation for climate change. Our chronosequence study assessed the influence of 6 years of high-density (H) and very-high-density (VH) SRCs on soil organic carbon (SOC) accumulation in an alluvial area of Piedmont (Italy) by investigating the effects of agronomic management (fertilization, irrigation, fertilization and irrigation, no treatment) using a spatial survey approach. A first sampling was performed at 40 points to characterize the variability of the initial SOC and other soil properties; 6 years after, a total of 80 samplings were carried out to verify changes in SOC. A mixed effect model procedure was used to evaluate the impact of 6 years of SRC and agronomic management on SOC, testing for autocorrelation among the model residuals. The results showed: (i) a higher accumulation potential of H-SRC (0.076 kg m−2 year−1) compared to VH-SRC (0.037 kg m−2 year−1); (ii) a significant positive influence of the initial SOC value and of fertilization associated with irrigation on the SOC sequestration; (iii) the importance of considering spatial variability at sites with high particle-size diversity in evaluating the SOC changes.
17
Shem-Tov, Shachar, Steve A. Fennimore, and W. Thomas Lanini. "Weed Management in Lettuce (Lactuca Sativa) with Preplant Irrigation." Weed Technology 20, no. 4 (December 2006): 1058–65. http://dx.doi.org/10.1614/wt-05-085.1.
Full textAbstract:
During dry weather, preplant irrigation of raised beds followed by shallow tillage to create a smooth planting bed is necessary to establish a good lettuce stand. Depletion of germinable weed seeds in the top 5 cm of soil by the sequence of preplant irrigation, followed 7 to 14 d later by shallow tillage to prepare a seedbed, reduces weed density in the subsequent crop. Preplant irrigation and tillage reduces weed density and, when used together with preplant herbicide, provides effective weed control in the cropping season. Preplant and in-crop weed densities resulting from furrow or sprinkler preplant irrigation, followed by shallow tillage and lettuce planting 7 or 14 d later, were compared with the no preplant irrigation control. During the 14-d preplant period, up to 127 weeds/m2emerged and were removed by shallow tillage before crop planting. Preplant irrigation and shallow tillage reduced in-crop weed density by up to 77% and reduced hand-weeding and crop-thinning time by up to 50% compared with the no preplant irrigation and no herbicide control. Delaying tillage for 14 d following preplant irrigation provided sufficient time for adequate heat unit accumulation (>120 growing degree days, base 10 C), allowing for many weeds to germinate and be killed by shallow tillage. However, 7 d between preplant irrigation and tillage resulted in less heat unit accumulation (<50 growing degree days, base 10 C) and less weed germination before tillage. Preplant irrigation together with pronamide at either 0.67 or 1.34 kg ai/ha reduced weed density compared with the no preplant irrigation. Effective use of preplant irrigation and preplant weed removal may increase the consistency of weed control with lower pronamide rates. Preplant irrigation followed by shallow tillage is an effective cultural practice to control in-crop weeds for conventional lettuce production.
18
Neilsen, D., and G. H. Neilsen. "Efficient Use of Nitrogen and Water in High-density Apple Orchards." HortTechnology 12, no. 1 (January 2002): 19–25. http://dx.doi.org/10.21273/horttech.12.1.19.
Full textAbstract:
In irrigated apple orchard systems, the magnitude and timing of plant demand for nitrogen (N) and retention of N in the root zone to allow root interception are important factors for efficient management of N fertilizer. Results from five experiments in high-density plantings of apple (Malus domestica) on dwarfing (`Malling 9') rootstocks are reported. All experimental plots received daily drip irrigation and N applied through the irrigation system (fertigation) with different regimes according to experimental design. Labelled fertilizer applications, whole tree excavation and partitioning and removal of N in fruit and senescent leaves were used to assess tree N demand. Nitrogen requirements ranged from 8 to 40 lb/acre (8.8 to 44 kg·ha-1) over the first 6 years after planting and N use efficiency was often low (<30%), likely because supply exceeded demand. Annual growth is supported by N remobilized from storage and taken up by roots. Root uptake of labelled fertilizer was negligible during early spring and the commencement of rapid uptake was associated with the end of remobilization and the start of shoot growth, rendering prebloom fertilizer applications ineffective. Thus timing of N supply to periods of high demand is crucial for improving efficiency. Comparisons were made to determine the effects on N leaching and tree N utilization of irrigation scheduled to meet evaporative demand and irrigation applied at a fixed rate. Water losses beneath the root zone were greater for fixed rate than scheduled irrigation during the coolest months (May, June and September) of irrigation application. Nitrogen leaching followed a similar pattern during times of N fertigation (May and June). Greater N use efficiency was also measured for trees when irrigation was scheduled to meet evaporative demand rather than applied at a fixed rate. The most N efficient management system was for trees receiving a low [50 ppm (mg·L-1)] fertigated N supply, at 0 to 4 or 4 to 8 weeks following bloom with scheduled irrigation.
19
Alves Souza, Silas, Joslanny Higino Vieira, Diego Bispo dos Santos Farias, Gustavo Henrique da Silva, and Catariny Cabral Aleman. "Impact of Irrigation Frequency and Planting Density on Bean’s Morpho-Physiological and Productive Traits." Water 12, no. 9 (September 4, 2020): 2468. http://dx.doi.org/10.3390/w12092468.
Full textAbstract:
The correct irrigation frequency relies on the plant population density to increase yield and efficiency in water use. A field experiment was carried out in 2019 to study the effect of three irrigation frequencies, one (F1), four (F2), and eight (F3) days, and four planting densities, 20 (D1), 24 (D2), 28 (D3), and 30 (D4) plants per m2, on the variables: soil moisture, actual water consumption, growth, grain yield, and water productivity of beans (Phaseolus vulgaris L.). The soil water balance was calculated based on the soil moisture, which was measured by tensiometers. The irrigation was done by a drip tape. The variation in soil moisture was greatly influenced by irrigation frequencies and planting densities in F3. Plant growth was not affected by treatments. Irrigation frequencies and planting densities have deeply affected the biometric and chlorophyll synthesis traits of beans. The highest yields were found in the treatments F1D3 (2968 kg ha−1), F1D4 (2997 kg ha−1), and F3D3 (2946 kg ha−1). For water productivity, treatments with F1 irrigation frequency and the higher planting densities were more efficient in water use. Overall, the results are useful for technicians and farmers who work with irrigation management on beans.
20
Sirait, Yacob, Wallace G. Pill, and Walter E. Kee. "Lima Bean (Phaseolus lunatus L.) Response to Irrigation Regime and Plant Population Density." HortScience 29, no. 2 (February 1994): 71–73. http://dx.doi.org/10.21273/hortsci.29.2.71.
Full textAbstract:
`Maffei-15' lima beans were subjected to three irrigation regimes (natural rainfall only, partial = 50 mm each week of rain or irrigation from first-flower bud to harvest, and full = 50 mm each week of rain or irrigation from planting to harvest), two between-row spacings (38 and 76 cm), and two in-row plant spacings (5 and 10 cm). The wider in-row spacing increased individual plant vegetative growth but had no effect on economic yield. The combination of 38-cm rows and partial irrigation provided the highest crop growth rate, plant dry matter, leaf area index, water-use efficiency, and economic yieid (equivalent to 3.3 t·ha-1).
21
Li, Yanrong, Jinxia Wang, Jikun Huang, Bihm Adhikari, and Liangzhi You. "Village-level supply reliability of groundwater irrigation in rural China." China Agricultural Economic Review 10, no. 3 (September 3, 2018): 354–71. http://dx.doi.org/10.1108/caer-05-2017-0086.
Full textAbstract:
Purpose The purpose of this paper is to examine the status of the supply reliability of groundwater irrigation, and discuss how it is affected by climate change and tubewell density in rural China. Design/methodology/approach This study is based on a nine-province village survey and secondary climate data. A Tobit model (or censored regression model) was used to estimate the determinants of supply reliability of groundwater irrigation. Findings Results show that the supply reliability of groundwater irrigation was 89 percent on average in the past three years. The non-linear relationship in the econometric results revealed that the 30-year annual temperature significantly influenced the supply reliability of groundwater irrigation. When the temperature rises above the turning point (6.30°C), it shifts from a positive to a negative relationship with the supply reliability of groundwater irrigation. The 30-year annual temperature in eight of the nine provinces (i.e. except for Jilin Province) was higher than the turning point. If the temperature increases by 20°C in the future, other factors being constant, the supply reliability of groundwater irrigation will decline by 20 percent. However, if precipitation increases by 10 percent, the supply reliability of groundwater irrigation could improve by 3 percent, while reducing precipitation by 10 percent will lower the supply reliability of groundwater irrigation by 3 percent. Increasing the density of tubewells considerably improves the supply reliability of groundwater irrigation. However, although increasing the density of tubewells may yield enough groundwater for irrigation, this one-sided approach raises sustainability concerns. Research limitations/implications Although increasing the density of tubewells may ensure that enough groundwater is available for irrigation, such a conclusion is one sided, and sustainability concerns should be raised in assessing this method of creating supply reliability. Originality/value This paper improves the understanding of the impact of climate variables on agriculture irrigation and water supply reliability in the micro scale, and provides a scientific basis for relevant policy making.
22
Kanatas, Panagiotis, Ioannis Gazoulis, and Ilias Travlos. "Irrigation Timing as a Practice of Effective Weed Management in Established Alfalfa (Medicago sativa L.) Crop." Agronomy 11, no. 3 (March 14, 2021): 550. http://dx.doi.org/10.3390/agronomy11030550.
Full textAbstract:
Irrigation is an agronomic practice of major importance in alfalfa (Medicago sativa L), especially in the semiarid environments of Southern Europe. Field experimentation was conducted in Western Greece (2016–2018) to evaluate the effects of irrigation timing on weed presence, alfalfa yield performance, and forage quality. In a randomized complete block design (four replications), two cultivars (“Ypati 84” and “Hyliki”) were the main plots, while three irrigation timings were the subplots (split-plot). The irrigation timings were IT-1, IT-2, and IT-3, denoting irrigation 1 week before harvest, 1 week after harvest, and 2 weeks after harvest, respectively. IT-1 reduced Solanum nigrum L. density by 54% and 79% as compared to IT-3 and IT-2, respectively. Chenopodium album L. density was the highest under IT-2. IT-3 resulted in 41% lower Amaranthus retroflexus L. density in comparison to IT-2, while the lowest values were observed under IT-1. Stand density and stems·plant−1 varied between years (p ≤ 0.05). Mass·stem−1 and alfalfa forage yield were affected by the irrigation timings (p ≤ 0.001). Total weed density and forage yield were negatively correlated in both the second (R2 = 87.013%) and the fourth (R2 = 82.691%) harvests. IT-1 and IT-3 increased forage yield, leaf per stem ratio, and crude protein as compared to IT-2. Further research is required to utilize the use of cultural practices for weed management in perennial forages under different soil and climatic conditions.
23
Asibi, Aziiba Emmanuel, Wen Yin, Falong Hu, Zhilong Fan, Zhiwen Gou, Hongwei Yang, Yao Guo, and Qiang Chai. "Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China." PeerJ 10 (January 19, 2022): e12762. http://dx.doi.org/10.7717/peerj.12762.
Full textAbstract:
Nitrogen fertilizers play a key role in crop production to meet global food demand. Inappropriate application of nitrogen fertilizer coupled with poor irrigation and other crop management practices threaten agriculture and environmental sustainability. Over application of nitrogen fertilizer increases nitrogen gas emission and nitrate leaching. A field experiment was conducted in China’s oasis irrigation area in 2018 and 2019 to determine which nitrogen rate, plant density, and irrigation level in sole maize (Zea mays L.) cropping system reduce ammonia emission and nitrate leaching. Three nitrogen rates of urea (46-0-0 of N-P2O5-K2O), at (N0 = 0 kg N ha−1, N1 = 270 kg N ha−1, and N2 = 360 kg N ha−1) were combined with three plant densities (D1 = 75,000 plants/ha−1, D2 = 97,500 plants/ha−1, and D3 = 120,000 plants/ha−1) with two irrigation levels (W1 = 5,250 m3/hm2 and W2 = 4,740 m3/hm2) using a randomized complete block design. The results showed that, both the main and interaction effects of nitrogen rate, plant density, and irrigation level reduced nitrate leaching (p < 0.05). In addition, irrigation level × nitrogen rate significantly (p < 0.05) reduced ammonia emission. Nitrate leaching and ammonia emission decreased with higher irrigation level and higher plant density. However, high nitrogen rates increased both nitrate leaching and ammonia emission. The study found lowest leaching (0.35 mg kg−1) occurring at the interaction of 270 kg N ha−1 × 120,000 plants/ha−1 × 4,740 m3/hm2, and higher plant density of 120,000 plants/ha−1 combined with 0 kg N ha−1 and irrigation level of 5,250 m3/hm2 recorded the lowest ammonia emission (0.001 kg N)−1. Overall, ammonia emission increased as days after planting increased while nitrate leaching decreased in deeper soil depths. These findings show that, though the contributory roles of days after planting, soil depth, amount of nitrogen fertilizer applied and year of cultivation cannot be undermined, it is possible to reduce nitrate leaching and ammonia emission through optimized nitrogen rate, plant density and regulated irrigation for agricultural and environmental sustainability.
24
Kang, Ying Bin, Kun Huang, and Abdurxt Rjap. "Analysis of Influence Factors of Irrigation Method in Detecting Compactness of Canal Bank." Applied Mechanics and Materials 238 (November 2012): 308–12. http://dx.doi.org/10.4028/www.scientific.net/amm.238.308.
Full textAbstract:
This paper introduces the actual operation method of detection of the degree of compaction of the canal bank by using irrigation method and summarizes the project experience of detection of the degree of compaction of the canal bank. Taking a channel engineering as an example, some influencing factors of the irrigation method to detect the density of gravel soils are analyzed, and the application of irrigation method in dry density test of the gravel soils is discussed.
25
Kelly, KB, and WK Mason. "Effects of irrigation timing on seedling establishment and productivity of subterranean clover pastures." Australian Journal of Experimental Agriculture 27, no. 4 (1987): 545. http://dx.doi.org/10.1071/ea9870545.
Full textAbstract:
Pure swards of subterranean clover were irrigated from late summer-autumn 1982 to autumn 1985. The period of irrigation varied, with 3 times of initial irrigation (1 February, 1 March and 1 April) and 2 times of final irrigation (mid October and mid November). Seedling establishment, DM production and herbage quality were measured in grazed swards. In each regenerating year, seedling density increased as the time of initial irrigation was delayed from February (5.2 seedlingddm2) to April (20.5 seedling/ dm2). For any time of initial irrigation, seedling density was increased by up to 100%, in plots which were irrigated until mid November in the previous spring. Dry matter yield was increased by early irrigation, with average yields of 11.1, 10.3 and 9.1 t/ha.year achieved for February, March and April as times of initial irrigation respectively. Continuing irrigation until November increased annual yield by 0.76 to 1.58 t DM/ha. The late spring irrigation treatment gave increased spring growth plus increased growth in the following autumn as a result of increased seedling density. The quality of the feed produced in autumn was lower than that produced in winter (in vitro DMD 68% compared with 75%), but was higher than the published DMD values for paspalum pastures in autumn. Digestibility in spring declined rapidly, from 75% in September to about 50% in early December. The implications of these findings are discussed with respect to the most effective use of irrigation water, the reliability of subterranean clover regeneration and the timing and quality of the feed produced.
26
Hadihardaja, Iwan K., and Neil S. Grigg. "Decision support system for irrigation maintenance in Indonesia: a multi-objective optimization study." Water Policy 13, no. 1 (January 14, 2011): 18–27. http://dx.doi.org/10.2166/wp.2010.051.
Full textAbstract:
Maintenance of irrigation infrastructure is essential to sustain food production and farmers' earnings. Given the shortage of funds for maintenance in developing countries, it is critical to understand the degradation of the function of irrigation systems so that optimal budget allocations can be made. A case study of Indonesia proposes an Infrastructure Density Index that can be used to justify budgets for regions with distinct characteristics. Current policy and practice in Indonesia is to allocate the budget uniformly, based on unit cost per hectare. Thus, the existing system provides unvarying budgets without considering the irrigation assets in each network system of a region. Regional differences should be taken into consideration during budget allocations since each region has different infrastructure characteristics related to the density of hydraulic structures, length of irrigation canals, and area of the irrigation system. A budgeting model has been developed by using non-linear programming and an analytic hierarchy process to promote more reasonable budgeting allocation policy. The case study focuses on seven irrigation regions in West Java Province, Indonesia. Fair budgeting strategy is illustrated by the relationship between structure density and the Budgeting Index.
27
Li, Qu, Chen, Yang, and Huang. "Effect of Planting Density on the Growth and Yield of Sunflower under Mulched Drip Irrigation." Water 11, no. 4 (April 10, 2019): 752. http://dx.doi.org/10.3390/w11040752.
Full textAbstract:
A field experiment was conducted to test the suitability of growing sunflower undermulched drip irrigation with saline water in the HID (Hetao Irrigation District), North China. Theexperiment included five planting densities in which the plant spacing was 30, 35, 40, 45, and 50 cmwith the same spacing (50 cm) between rows. The results indicated that mulched drip irrigationwith saline water was more water‐saving than traditional ground irrigation using fresh water, whilethe irrigation quota increased with the increase of planting density. Little difference of soilsalinization was found for the treatments in the 50–100 cm soil layer, which indicated that additionalmeasures should be taken for salt balance with saline water irrigation. The height and leaf area index(LAI) of sunflower increased in response to the increase of plant density, and the head dry mattertransferred to the stem at plant densities higher than 47,619 plants/hm2. Though the grain weightand 1000‐seed weight decreased with increasing plant density, the achene yield and biomassproduction increased. This research suggests that a plant spacing of 35 cm with 50 cm of row spacingis more suitable for sunflower mulched drip irrigation with saline water at concentrations of 3.0g∙L−1.
28
BEN, LUIS HUMBERTO BAHÚ, MARCIA XAVIER PEITER, ADROALDO DIAS ROBAINA, ANA RITA COSTENARO PARIZI, and GIDEON UJACOV DA SILVA. "INFLUENCE OF IRRIGATION LEVELS AND PLANT DENSITY ON "SECOND-SEASON" MAIZE." Revista Caatinga 29, no. 3 (September 2016): 665–76. http://dx.doi.org/10.1590/1983-21252016v29n317rc.
Full textAbstract:
ABSTRACT This study assessed the effect of different irrigation levels and plant densities on maize crops cultivated during the second season in the Western Border region of the State of Rio Grande do Sul. This work was conducted at the Federal Institute of Farroupilha - Alegrete Campus/RS - between January and June 2014. Treatments were arranged in a completely randomized 5 × 4 factorial design, with 3 replicates each. Irrigation of fixed amounts of water that were based on the evapotranspiration of the culture (Etc): 0, 50, 75, 100, and 125% of Etc were applied at 5-day intervals. Four densities of plants were defined (4, 7, 10, and 13 plants m-2). We assessed number of maize ears per plant, number of grains per ear, aboveground dry matter, mass of 100 grains, harvest index, and grain productivity. The number of grains per ear, mass of 100 grains, and grain yield were influenced by irrigation levels. Plant density and water depth influenced the number of grains per ear, the mass of 100 grains, and grain productivity. The highest yield of winter maize grain was achieved with a combination of 13 plants per m-2 and an irrigation level of 100% of Etc. Specific densities of plants maximized the yield of maize at each irrigation level, demonstrating that choice of plant density is a critical variable in the second crop of maize, and significantly influences the components of production.
29
Daga, Priya, Hemant Asrani, Shanin Farista, and Praveen Mishra. "Comparative Evaluation of Antimicrobial Efficacy of Neem, Miswak, Propolis, and Sodium Hypochlorite against Enterococcus faecalis using EndoVac." International Journal of Prosthodontics and Restorative Dentistry 7, no. 2 (2017): 60–65. http://dx.doi.org/10.5005/jp-journals-10019-1178.
Full textAbstract:
ABSTRACT Aim To compare the antimicrobial efficacy of herbal irrigants neem, miswak, propolis with sodium hypochlorite using conventional needle irrigation and EndoVac irrigation system against Enterococcus faecalis. Materials and methods A total of 120 extracted single-rooted mandibular premolar teeth were infected for 21 days with E. faecalis after instrumentation with ProTaper system. Before irrigation procedure, dentinal shavings were collected in 1 mL of sterile broth and incubated. The optical density of each broth was measured using digital colorimeter and initial readings were recorded. Samples were then divided into four groups of 30 teeth each – Group I: Sodium hypochlorite irrigation, group II: Neem irrigation, group III: Miswak irrigation, group IV: propolis irrigation. Each group was further divided into two subgroups – (a) EndoVac irrigation (b) conventional needle irrigation. After irrigation, dentinal shavings were collected and optical density recorded. The values were analyzed statistically with Student's t test and analysis of variance followed by Tukey's honest significant difference test; p-value < 0.05 was considered to be statistically significant. Results The postirrigation optical densities in all the groups were significantly lower than preirrigation values. Sodium hypochlorite demonstrated better antimicrobial efficacy followed by propolis, neem, and miswak. Differences in optical density values for all irrigants are higher in EndoVac (p < 0.0001) compared with needle (p = 0.0009) group, but it failed to reach statistical significance. Conclusion Sodium hypochlorite proved to be a better irrigant followed by propolis, neem, and miswak. EndoVac irrigation system was more effective for elimination of E. faecalis than needle irrigation group. How to cite this article Daga P, Asrani H, Farista S, Mishra P. Comparative Evaluation of Antimicrobial Efficacy of Neem, Miswak, Propolis, and Sodium Hypochlorite against Enterococcus faecalis using EndoVac. Int J Prosthodont Restor Dent 2017;7(2):60-65.
30
Liu, Donghua, Qianmin Jia, Juan Li, Peng Zhang, Xiaolong Ren, and Zhikuan Jia. "Increased photosynthesis and grain yields in maize grown with less irrigation water combined with density adjustment in semiarid regions." PeerJ 8 (October 6, 2020): e9959. http://dx.doi.org/10.7717/peerj.9959.
Full textAbstract:
In order to design a water-saving and high-yield maize planting model suitable for semiarid areas, we conducted trials by combining supplementary irrigation with different planting densities. Three planting densities (L: 52,500, M: 75,000, and H: 97,500 plants ha–1) and four supplementary irrigation modes (NI: no irrigation; IV: 375 m3 ha–1 during the 11-leaf stage; IS: 375 m3 ha–1 in the silking stage; and IVS: 375 m3 ha–1 during both stages) were tested. The irrigation treatments significantly increased the leaf relative water content, but the high planting density significantly decreased the relative water content during the silking and filling stages. After supplementary irrigation during the 11-leaf stage, IV and IVS significantly increased the photosynthetic capacity, but decreased the leaf water use efficiency. IS and IVS significantly increased the photosynthetic capacity after supplementary irrigation in the silking stage over two years. During the filling stage, IV, IS, and IVS increased the two-year average net photosynthetic rate by 17.0%, 27.2%, and 30.3%, respectively. The intercellular CO2 concentration increased as the density increased, whereas the stomatal conductance, transpiration rate, net photosynthetic rate, and leaf water use efficiency decreased, and the high planting density significantly reduced the leaf photosynthetic capacity. The highest grain yield was obtained using the IVS treatment under the medium planting density, but it did not differ significantly from that with the IS treatment. Furthermore, the IVS treatment used two times more water than the IS treatment. Thus, the medium planting density combined with supplementary irrigation during the silking stage was identified as a suitable water-saving planting model to improve the photosynthetic capacity and grain yield, and to cope with drought and water shortages in semiarid regions.
31
Cockerham, Stephen T. "Irrigation and planting density affect river red gum growth." California Agriculture 58, no. 1 (January 2004): 40–43. http://dx.doi.org/10.3733/ca.v058n01p40.
Full text
32
Argerich, C. A., N. S. Aquindo, and P. Navarro. "OPTIMIZING PLANT DENSITY IN PROCESSING TOMATOES UNDER DRIP IRRIGATION." Acta Horticulturae, no. 971 (January 2013): 71–76. http://dx.doi.org/10.17660/actahortic.2013.971.5.
Full text
33
Sanderson, K. R., and S. A. E. Fillmore. "Response of broccoli (Brassica oleracea var. italica) yield and hollow stem to plant density, trickle irrigation and transplanting date." Canadian Journal of Plant Science 90, no. 5 (September 1, 2010): 729–35. http://dx.doi.org/10.4141/cjps09167.
Full textAbstract:
Maximizing yield and quality of processing broccoli (Brassica oleracea L. var. italica) is critical to successful production in Atlantic Canada. Field studies were conducted from 2004 to 2006 to evaluate the effect of plant density and trickle irrigation on the yields and incidence of hollow stem for early and late transplanting of broccoli. Treatments consisted of five plant densities ranging from 3.17 to 6.35 plants m–2. Each plant density was either not irrigated or trickle irrigated to maintain at least 25 mm total precipitation per week. The highest marketable yield was achieved at 5.56 plants m–2 when grown in an early transplanting with trickle irrigation in a single row with 90 cm between the row and 20 cm within the row. Overall, earlier transplanting dates were more productive. Trickle irrigation increased marketable yield by an average of 12% over the 3 yr of tests. Average head weight, head diameter, and the incidence of hollow stem decreased as plant density increased. Leaf tissue N was not affected by plant density, trickle irrigation or transplanting date.Key words: Brassica oleracea L. italica, plant density, yield, growth
34
Blahovec, J. "Density and shape characteristics of Agria tubers cultivated at different conditions." Research in Agricultural Engineering 51, No. 1 (February 7, 2012): 1–6. http://dx.doi.org/10.17221/4894-rae.
Full textAbstract:
Potato variety Agria was cultivated in different fertilising and/or irrigation regimes. Individual tuber dimension and the individual tuber density were studied two months after the harvest with aim to find some potential relation between tuber density and its shape. The stem-bud density gradient was also studied by determination the density of the stem, middle and bud parts of the individual tubers. The results of the measurements brought information on relatively variable parameters that slightly depended on the cultivation conditions.
35
Assis, Gleice Aparecida, Franscinely Aparecida Assis, Myriane Stella Scalco, Francisco José Toloza Parolin, Iraci Fidelis, Jair Campos Moraes, and Rubens José Guimarães. "Leaf miner incidence in coffee plants under different drip irrigation regimes and planting densities." Pesquisa Agropecuária Brasileira 47, no. 2 (February 2012): 157–62. http://dx.doi.org/10.1590/s0100-204x2012000200002.
Full textAbstract:
The objective of this work was to evaluate the effect of different drip irrigation regimes and planting densities on the incidence of the leaf miner, Leucoptera coffeella, in arabica coffee plants for one year. The experiment was carried out in 2008, in a complete randomized block design, in a split-plot in time arrangement, with four replicates. The treatments consisted of four drip irrigation regimes - soil water balance, irrigations at 20 and 60 kPa soil tensions, and a nonirrigated treatment -, which were distributed at three plant densities: 2, 500, 5, 000, and 10, 000 plants per hectare. The evaluations were made on a monthly basis between January and December 2008. The highest pest occurrence period was from August to November, a season with low-air relative humidity preceded by a drought period. Irrigated coffee plants showed an incidence of intact mines 2.2 times lower than that of nonirrigated plants. Irrigation and increasing of plant density contribute to the reduction of coffee leaf miner occurrence.
36
Pittenger, Dennis R., David A. Shaw, Donald R. Hodel, and William E. Richie. "Influence of Irrigation Scheduling on Groundcover Performance." HortScience 30, no. 4 (July 1995): 799A—799. http://dx.doi.org/10.21273/hortsci.30.4.799a.
Full textAbstract:
The performance of six landscape groundcover species was evaluated when irrigated at 30% of ET0 at irrigation schedules of three times per week, once per week, once every 2 weeks, and once every 4 weeks. Potentilla tabernaemontani could not be sustained under any of the treatments. For the other species (Baccharis pilularis, Drosanthemum hispidum, Vinca major, Osteospermum fruticosum, and Hedera helix) there were no season-long differences in a species' performance or density due to irrigation frequency, but there were significant differences among species across irrigation treatments. Drosanthemum and Osteospermum provided good overall appearance and density consistently through the season. Baccharis maintained acceptable performance most of the irrigation season, while Vinca and Hedera became unacceptable in appearance in mid-season. Soil moisture content differed among species, but was not consistently different between irrigation treatments.
37
Hamido, Said A., and Kelly T. Morgan. "The Effect of Irrigation Rate on the Water Relations of Young Citrus Trees in High-Density Planting." Sustainability 13, no. 4 (February 6, 2021): 1759. http://dx.doi.org/10.3390/su13041759.
Full textAbstract:
The availability and proper irrigation scheduling of water are some of the most significant limitations on citrus production in Florida. The proper volume of citrus water demand is vital in evaluating sustainable irrigation approaches. The current study aims to determine the amount of irrigation required to grow citrus trees at higher planting densities without detrimental impacts on trees’ water relation parameters. The study was conducted between November 2017 and September 2020 on young sweet orange (Citrus sinensis) trees budded on the ‘US-897’ (Cleopatra mandarin x Flying Dragon trifoliate orange) citrus rootstock transplanted in sandy soil at the Southwest Florida Research and Education Center (SWFREC) demonstration grove, near Immokalee, Florida. The experiment contained six planting densities, including 447, 598, and 745 trees per ha replicated four times, and 512, 717, and 897 trees per ha replicated six times. Each density treatment was irrigated at 62% or 100% during the first 15 months between 2017 and 2019 or one of the four irrigation rates (26.5, 40.5, 53, or 81%) based on the calculated crop water supplied (ETc) during the last 17 months of 2019–2020. Tree water relations, including soil moisture, stem water potential, and water supplied, were collected periodically. In addition, soil salinity was determined. During the first year (2018), a higher irrigation rate (100% ETc) represented higher soil water contents; however, the soil water content for the lower irrigation rate (62% ETc) did not represent biological stress. One emitter per tree regardless of planting density supported stem water potential (Ψstem) values between −0.80 and −0.79 MPa for lower and full irrigation rates, respectively. However, when treatments were adjusted from April 2019 through September 2020, the results substantially changed. The higher irrigation rate (81% ETc) represented higher soil water contents during the remainder of the study, the lower irrigation rate (26.5% ETc) represents biological stress as a result of stem water potential (Ψstem) values between −1.05 and −0.91 MPa for lower and higher irrigation rates, respectively. Besides this, increasing the irrigation rate from 26.5% to 81%ETc decreased the soil salinity by 33%. Although increasing the planting density from 717 to 897 trees per hectare reduced the water supplied on average by 37% when one irrigation emitter was used to irrigate two trees instead of one, applying an 81% ETc irrigation rate in citrus is more efficient and could be managed in commercial groves.
38
Leskovar, Daniel I., Shinsuke Agehara, Kilsun Yoo, and Nuria Pascual-Seva. "Crop Coefficient-based Deficit Irrigation and Planting Density for Onion: Growth, Yield, and Bulb Quality." HortScience 47, no. 1 (January 2012): 31–37. http://dx.doi.org/10.21273/hortsci.47.1.31.
Full textAbstract:
Agricultural communities in the semiarid regions of the world are constantly being affected by water scarcity, increased regulations restricting water use, strong competition for irrigation water with the urban sector, and severe drought periods. Conversely, the consumer demand for high-quality and nutritious foods is increasing rapidly. A 2-year field study evaluated growth, yield, and bulb quality in response to precision planting density and deficit irrigation of onion (Allium cepa L.) in southwest Texas. Seeds of short-day sweet onion cv. Texas Grano 1015Y were planted in the field on 11 Nov. 2007 and 30 Oct. 2008 at two planting densities (PDs), 397,000 (standard) and 484,000 (high) seeds/ha. Three irrigation rates using growth stage-specific crop coefficients and subsurface drip were imposed after plants were fully established, 100%, 75%, and 50% crop evapotranspiration rates (ETc). Total rainfall plus irrigation received for each irrigation rate were 594, 501, and 413 mm in 2008 and 662, 574, and 486 mm in 2009. In both seasons, there were consistent trends in growth, yield, and quality parameters. Leaf fresh weight was unaffected by PD but was reduced by deficit irrigation at 50% ETc. Although increasing planting density reduced the average bulb size by 12%, it increased the number of marketable bulbs by 21% to 33% and marketable yield by 7% to 14%. In contrast, deficit irrigation showed a trend to reduce both the number of bulbs and bulb size with yield reductions of 8% to 13% at 75% ETc and 19% to 27% at 50% ETc. Neither planting density nor deficit irrigation rate had a significant effect on soluble solids content, pungency, or quercetin contents. These results suggest that growers of short-day onions in semiarid regions could adjust PDs to target high-value bulb sizes. Implementing water-conserving practices (deficit irrigation at 75% ETc rate) would result in a decrease of high-value bulb grades and modest losses in yield but not flavor or nutritional components.
39
Zhang, Guoqiang, Bo Ming, Dongping Shen, Ruizhi Xie, Peng Hou, Jun Xue, Keru Wang, and Shaokun Li. "Optimizing Grain Yield and Water Use Efficiency Based on the Relationship between Leaf Area Index and Evapotranspiration." Agriculture 11, no. 4 (April 3, 2021): 313. http://dx.doi.org/10.3390/agriculture11040313.
Full textAbstract:
Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.
40
Yang, C. H., Q. Chai, and Huang GB. "Root distribution and yield responses of wheat/maize intercropping to alternate irrigation in the arid areas of northwest China ." Plant, Soil and Environment 56, No. 6 (June 3, 2010): 253–62. http://dx.doi.org/10.17221/251/2009-pse.
Full textAbstract:
A field experiment was conducted to investigate the effects of alternate irrigation (AI) on root distribution and yield of wheat (Triticum aestivum L.)/maize (Zea mays L.) intercropping system during the period of 2007–2009 in an oasis of arid north-west China. Five treatments, i.e. sole wheat with conventional irrigation (W), sole maize with alternate irrigation (AM), sole maize with conventional irrigation (CM), wheat/maize intercropping with alternate irrigation (AW/M), and wheat/maize intercropping with conventional irrigation (CW/M). The results showed that root growth was significantly enhanced by alternate irrigation (AI), root weight density (RWD), root length density (RLD) and root-shoot ratios (R/S) in AI treatments were all higher than those in conventional irrigation (CI) treatments. Moreover, intercropped wheat and maize also had a greater root development at a majority of soil depths than wheat and maize in monoculture. In three years, AW/M always achieved the highest total seed yield under different treatments. Higher yield and reduced irrigation resulted in higher water use efficiency (WUE) for the AW/M treatment. Our results suggest that AI should be a useful water-saving irrigation method on wheat/maize intercropping in arid oasis field where intercropping planting is decreased because of limited water resource.
41
Jeong, GyeSoon, and John M. Brown. "DISPERSAL OF TRICHODERMA VIA IRRIGATION WATER." HortScience 27, no. 6 (June 1992): 631g—631. http://dx.doi.org/10.21273/hortsci.27.6.631g.
Full textAbstract:
Trichoderma has been known to control soil-borne pathogens and to enhance plant growth and development. The objective of the study was to evaluate dispersal of Trichoderma via irrigation water in container production. 3.81 × 30 cm PVC pipes were filled with Sunshine Mix #5 up to 25 cm. Ten tomato seeds, boiled and coated with T. harzianum, were placed at 0.5 cm depth in each pipe. All treatments were irrigated carefully with 100 ml of DD water from top every 2 days. Before and one hour after irrigation the potting mix was sampled from 5 depths at 5.5 cm intervals every 2 days for 8 days to determine Trichoderma density. Trichoderma density was significantly higher in after irrigation. Trichoderma dispersed up to 25 cm deep in container potting mix after 4 days via irrigation water. This study successfully demonstrates that Trichoderma can be rapidly dispersed via irrigation water.
42
Sharma, B. R. "Effect of time and amount of first irrigation on the root distribution and fodder yield of oats." Journal of Agricultural Science 108, no. 2 (April 1987): 299–303. http://dx.doi.org/10.1017/s0021859600079296.
Full textAbstract:
SummaryWater-use efficiency and forage yield of irrigated oats depend to a large extent on water application during initial growth. Root distribution, growth and fodder yield of oats as influenced by time and amount of first irrigation were studied in the field for 2 years. Root-weight density of each layer, profile-root-weight density and yields decreased progressively when the first irrigation was delayed. Application of a small amount of irrigation (20 mm) at day 25 proved to be better than applications of 50 or 70 mm at later stages.
43
Viana, Felipe Jorge, Fernando França da Cunha, Mayara Oliveira Rocha, and Job Teixeira Oliveira. "Water rationalization in Brazilian irrigated agriculture." Agronomy Science and Biotechnology 8 (February 25, 2022): 1–15. http://dx.doi.org/10.33158/asb.r154.v8.2022.
Full textAbstract:
Freshwater, an essential asset for the life of living beings and one of the main resources for the development of nations. About 70% of the freshwater on the planet is used by irrigated agriculture. In view of the increasing population density for food production, considering the limitations of agricultural processes, countless producers are looking for viable alternatives that provide them with greater production, irrigation being one of them. This bibliographic review aims to summarize information on the topic: Rationalization of Water Resources and Environmental Impacts in Irrigated Agriculture, based on searches in books, scientific articles, and publications by reputable organizations related to the topic. In these, aspects related to water scarcity, the challenges of irrigated agriculture, contamination of water resources, the reuse of water for irrigation, the quality of reused water, and adequacy of water for irrigation are dealt with. The need for conservation of water resources and awareness of the irrigator regarding the rational use of water and the environmental impacts inherent to the irrigation process is evident, therefore, the intention is to consolidate increasingly sustainable agriculture.
44
Taylor, AJ, and VL Marble. "Lucerne irrigation and soil water use during bloom and seed set on a red-brown earth in south-eastern Australia." Australian Journal of Experimental Agriculture 26, no. 5 (1986): 577. http://dx.doi.org/10.1071/ea9860577.
Full textAbstract:
Lucerne (Medicago sativa L.) cv. WL45 1, grown on a shallow red-brown earth, was subjected to different irrigation frequencies during bloom to determine the effect on seed yield. The highest yield of 1105 kg ha-1 was produced when the crop was irrigated at an accumulated Epan of 75 mm between irrigations. Yields declined to 528 kg ha-1 as the interval between irrigations increased and the total amount of water applied during bloom was reduced as a consequence. Seed yield was positively correlated with total top growth, number of stems, number of racemes with pods and number of seeds per pod. Neither individual seed weight nor number of pods per raceme was influenced by the irrigation treatments. Soil water extraction by the crop was confined mainly to the 0-1.2 m depth. However, highest seed yields were produced when soil water extraction was confined to the 0-0.6 m depth by regular irrigation. About 16% of the available water in the 0.6-1.2 m depth and 89% of the available water in the 1.2-1.8 m depth could not be extracted by the crop. Failure to extract water from the lower subsoil was attributed to soil physical restrictions and lack of adequate root density.
45
Asibi, Aziiba Emmanuel, Falong Hu, Zhilong Fan, and Qiang Chai. "Optimized Nitrogen Rate, Plant Density, and Regulated Irrigation Improved Grain, Biomass Yields, and Water Use Efficiency of Maize at the Oasis Irrigation Region of China." Agriculture 12, no. 2 (February 6, 2022): 234. http://dx.doi.org/10.3390/agriculture12020234.
Full textAbstract:
Nitrogen is a key factor in maize (Zea mays L.) grain and biomass production. Inappropriate application with sub-optimum plant density and irrigation can lead to low productivity and inefficient use. A two-year field experiment was conducted to determine which nitrogen rate, plant density, and irrigation level optimize grain, biomass yield, and water use efficiency. Three nitrogen rates of urea (46–0–0 of N–P2O5–K2O) (N0 = 0 kg N ha−1, N1 = 270 kg N ha−1, and N2 = 360 kg N ha−1), with three maize densities (D1 = 75,000 plants ha−1, D2 = 97,500 plants ha−1, and D3 = 120,000 plants ha−1), and two irrigation levels (W1 = 5250 m3/hm2 and W2 = 4740 m3/hm2) were investigated. The results show that both grain and biomass yields were affected by the main factors. The interaction between nitrogen rate and irrigation level significantly (p < 0.001) affected grain yield but not biomass. It was observed that the grain yield increased correspondingly with nitrogen rate and plant density, while it decreased as the irrigation level increased. Water use efficiency was significantly (p < 0.001) affected by the main factors and their interactions. Nevertheless, water use efficiency was highest at (5250 m3/hm2) × 270 kg N ha−1; × 360 kg N ha−1 × 120,000 plants ha−1 and increased from 62% to 68%. In addition, the highest biomass yield was recorded at 5250 m3/hm2 × 270 kg N ha−1; × 360 kg N ha−1 × 120,000 plants ha−1 while the interaction of either irrigation level with 0 and 270 kg ha−1 or 97,500 and 120,000 plants ha−1 yielded the lowest water use efficiency. Thus, optimized nitrogen rates, plant density, and alternate irrigation levels can support optimum grain and biomass yields. It can also improve nitrogen and water use efficiency in maize production.
46
Kelly, K. B., C. R. Stockdale, and W. K. Mason. "The productivity of irrigated legumes in northern Victoria. 1. Effect of irrigation interval." Australian Journal of Experimental Agriculture 45, no. 12 (2005): 1567. http://dx.doi.org/10.1071/ea03212.
Full textAbstract:
An experiment was undertaken to determine the production and water use of pure swards of white clover (Trifolium repens L. cv. Haifa), red clover (Trifolium pratense L. cv. Redquin) and lucerne (Medicago sativa L. cv. Validor) between December 1987 and December 1990. The experiment was a split plot design with 3 irrigation interval treatments, which were the main plots, and 3 legume species, which were the subplots, all of which were replicated 4 times. Irrigation frequency was determined by evaporation minus rainfall (E-R) and was scheduled to occur at intervals of about 40, 80 or 120 mm of cumulative E-R. Annual amounts of harvested dry matter (DM) ranged from 8 to 22 t/ha depending on irrigation and species treatment. There was an interaction (P<0.05) between irrigation interval and species during each irrigation season. White clover DM harvested was reduced (P<0.05) by an average of 23 and 41%, respectively, as irrigation intervals were extended beyond 40 mm E-R (where up to 12 t DM/ha was recorded in an irrigation season). The decline in white clover growth in the less frequently irrigated treatments, relative to the 40 mm E-R irrigation treatment, was most pronounced between December and February, the months of highest evaporative demand, when these swards were 30 and 52% less productive (80 and 120 mm E-R, respectively). This compared with reductions of 16 and 32%, respectively, for red clover and 1 and 4%, respectively, for lucerne during the same period. Red clover, a dense productive stand initially, lost vigour and density in the second summer of this experiment, and from February in the second year was not harvested. However, for the period during which it was harvested, red clover production was reduced (P<0.05) by 21%, on average, when the irrigation interval was 120 mm E-R compared with the 40 and 80 mm E-R irrigation treatments. The production of lucerne was not affected (P>0.05) by the range of irrigation frequencies used in this experiment, although its crown density in the most frequent irrigation treatment was 30% less than in the 2 less frequently irrigated treatments when measurements were terminated in December 1990. However, after the first year, the lucerne swards were all highly productive, producing up to 21 t DM/ha in an irrigation season. For white clover to be productive, frequent irrigation is essential. However, all the indices of plant and sward performance measured during intensive studies showed that frequent irrigation of white clover resulted in earlier onset of water stress relative to the less frequent irrigation intervals. Despite this earlier onset of water stress, the yield advantage of frequent irrigation was large. Red clover and lucerne were less reliant on frequent irrigations to maintain productivity than white clover. However, red clover may need to be re-sown on a regular basis in the northern Victorian environment because of its failure to persist beyond 2 years. It is suggested that lucerne should be considered in preference to white clover because of its greater water use efficiency and its less critical reliance on irrigation management to maintain productivity.
47
Parthasarathi, T., K. Vanitha, S. Mohandass, Eli Vered, and V. Meenakshi. "Variation in rice root traits assessed by phenotyping under drip irrigation." F1000Research 6 (February 10, 2017): 125. http://dx.doi.org/10.12688/f1000research.9938.1.
Full textAbstract:
Background: Roots are the key elements in water saving rice cultivation. So, the response of rice roots are to be phenotyped under varied drip irrigation treatments. Methods: This study describes an investigation on rice root phenotyping under drip irrigation treatments in split-split plot design. Two lateral spacing levels (0.8 and 1.2m), two depths of irrigation (5-10 and 15-20 cm) by solar powered and well operated irrigation were tested using TNRH 180, JKRH 3333 and ADT(R)45 rice genotypes during the summer season (2013 & 2014) in Coimbatore, India. Conventional aerobic irrigation was considered as control. Results and Discussion: An increased root length, root density (length and weight), root Adinosine Tri Phosphotase enzyme activity, root volume and filled grain percentage were favored in aerobic rice under the conditions of 0.8m lateral distance with 5-10cm depth of sub surface drip irrigation (SDI). Improved root characteristics were observed in JKRH 3333 rice hybrid, and root density and thickness favored the filled grains and yield increment in rice by drip irrigation. The 0.8m lateral distance laid out at 5-10cm depth SDI proliferated more roots at subsurface soil layer with significant yield increment in rice.
48
Rogers, M. E., A. R. Lawson, and K. B. Kelly. "Lucerne yield, water productivity and persistence under variable and restricted irrigation strategies." Crop and Pasture Science 67, no. 5 (2016): 563. http://dx.doi.org/10.1071/cp15159.
Full textAbstract:
Lucerne (Medicago sativa L.) has the potential to be grown widely under water-limiting conditions in the dairy region of northern Victoria and southern New South Wales, Australia, possibly because of its greater water productivity and because irrigation management of lucerne can be more flexible compared with other forage species. A large-scale field experiment was conducted at Tatura in northern Victoria, over 5 years to determine the effects of limiting (deficit) and non-limiting irrigation management on the dry matter (DM) production, water productivity (irrigation and total water productivity) and stand density (or persistence) of lucerne. Nine irrigation treatments were imposed that included full irrigation, partial irrigation and no irrigation in either a single, or over consecutive, irrigation seasons. In the fifth year of the experiment, all plots received the full irrigation treatment to examine plant recovery from the previous irrigation treatments. In any one year, there was a linear relationship between DM production and total water supply (irrigation plus rainfall plus changes in soil water) such that DM production decreased as the total water supply – due to deficit irrigation – decreased. Over the 5 years, annual DM production ranged from 1.4 to 17.7 t DM ha–1 with the highest production occurring in plots that received full irrigation. Irrigation water productivity was inversely related to the amount of water used and was higher in the treatments that had only been partially irrigated for that year compared with the treatments that had been fully watered for that year. Total water productivity values were significantly lower only in the treatments that had not been irrigated for that year, and there was little difference between the treatments that were only partially watered during the year and the fully watered treatments (range 9.1–12.2 kg DM ha–1 mm–1 for Year 4). There was no significant reduction in plant density or plant persistence in those plots where deficit irrigation had been imposed. However, the high irrigation regime and poor drainage in the fully irrigated border-check plots significantly reduced plant density and allowed weed infestation in the fifth year of the experiment. These results suggest that, although lucerne DM production is directly related to total water use and may be significantly reduced in the irrigation regions of south-eastern Australia in seasons when water is restricted, the lucerne stand is able to fully recover once a full irrigation regime is resumed. This makes lucerne an ideal forage species for situations when water is limiting.
49
Ferrarezi, Rhuanito S., Arun D. Jani, H. Thomas James, Cristina Gil, Mark A. Ritenour, and Alan L. Wright. "Sweet Orange Orchard Architecture Design, Fertilizer, and Irrigation Management Strategies under Huanglongbing-endemic Conditions in the Indian River Citrus District." HortScience 55, no. 12 (December 12, 2020): 2028–36. http://dx.doi.org/10.21273/hortsci15390-20.
Full textAbstract:
The prevalence of Huanglongbing (HLB) in Florida has forced growers to search for new management strategies to optimize fruit yield in young orchards and enable earlier economic returns given the likelihood of HLB-induced yield reductions during later years. There has been considerable interest in modifying orchard architecture design and fertilizer and irrigation management practices as strategies for increasing profitability. Our objectives were to evaluate how different combinations of horticultural practices including tree density, fertilization methods, and irrigation systems affect growth, foliar nutrient content, fruit yield, and fruit quality of young ‘Valencia’ sweet orange [Citrus sinensis (L.) Osbeck] trees during the early years of production under HLB-endemic conditions. The study was conducted in Fort Pierce, FL, from 2014 to 2020 on a 1- to 7-year-old orchard and evaluated the following treatments: standard tree density (358 trees/ha) and controlled-release fertilizer with microsprinkler irrigation (STD_dry_MS), high tree density (955 trees/ha) with fertigation and microsprinkler irrigation (HDS_fert_MS), and high tree density with fertigation and double-line drip irrigation (HDS_fert_DD). Annual foliar nutrient concentrations were usually within or higher than the recommended ranges throughout the study, with a tendency for decreases in several nutrients over time regardless of treatment, suggesting all fertilization strategies adequately met the tree nutrient demand. During fruit-bearing years, canopy volume, on a per-tree basis, was higher under STD_dry_MS (6.2–7.2 m3) than HDS_fert_MS (4.3–5.3 m3) or HDS_fert_DD (4.9–5.9 m3); however, high tree density resulted in greater canopy volume on an area basis, which explained the 86% to 300% increase in fruit yield per ha that resulted in moving from standard to high tree density. Although fruit yields per ha were generally greatest under HDS_fert_MS and HDS_fert_DD, they were lower than the 10-year Florida state average (26.5 Mg·ha−1) for standard tree density orchards, possibly due to the HLB incidence and the rootstock chosen. Although tree growth parameters and foliar nutrient concentrations varied in response to treatments, management practices that included high tree density and fertigation irrespective of irrigation systems produced the highest fruit yields and highest yield of solids. Soluble solids content (SSC) and titratable acidity (TA) were lower, and the SSC-to-TA ratio was highest under STD_dry_MS in 2016–17, with no treatment effects on quality parameters detected in other years. Both drip and microsprinkler fertigation methods sufficiently met tree nutrient demand at high tree density, but additional research is needed to determine optimal fertilization rates and better rootstock cultivars in young high-density sweet orange orchards under HLB-endemic conditions in the Indian River Citrus District.
50
Zoz, Tiago, Fábio Steiner, André Zoz, Deise Dalazen Castagnara, Travis Wilson Witt, Mauricio Dutra Zanotto, and Dick Lindsey Auld. "Effect of row spacing and plant density on grain yield and yield components of Crambe abyssinica Hochst." Semina: Ciências Agrárias 39, no. 1 (February 16, 2018): 393. http://dx.doi.org/10.5433/1679-0359.2018v39n1p393.
Full textAbstract:
Understanding the influence of row spacing and plant density on grain yield and yield components of crambe is critical in order to obtain higher grain yields. Therefore, the objective of this study was to evaluate the effects of row spacing and plant density on grain yield and its components in crambe in two distinct regions of Brazil (Marechal Candido Rondon-PR, MCR-PR, and Botucatu-SP, BTU-SP). Narrow and wide row spacing (0.20 and 0.40 m) combined with four plant densities (15, 25, 35, and 45 plants m-1) were evaluated in a randomized block layout with four replications in a 2 × 4 factorial design. The experiment at BTU-SP was run under rainfed conditions with supplementary irrigation, whereas the experiment at MCR-PR was run under rainfed conditions without supplementary irrigation. Both experiments were run in soils classified as Oxisols. There was no interaction between row spacing and plant density. Highest grain yield with supplementary irrigation was observed at 0.20 m row spacing. Without irrigation, row spacing did not affect grain yield owing to the plasticity of crop. The highest grain yield was observed with approximately 30 plants m-1 at both experimental locations. A strong negative correlation was observed between final plant population and number of grains per plant. There was high plant mortality, particularly at high plant densities cultivated under irrigation. Higher mortality occurred because of high intraspecific competition and a larger disease incidence due to the higher humidity in the irrigated experiment. A mechanism of self-adjustment by plant density was observed in crambe, with its intensity dependent on plant density and environmental conditions, such as water and nutrient availability and light incidence.