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1
Tursunov, Sotvoldi. "Does wheat yield depend on variety and planting time?" E3S Web of Conferences 258 (2021): 04033. http://dx.doi.org/10.1051/e3sconf/202125804033.
Testo completoAbstract (sommario):
This article describes in detail the influence of sowing dates on the growth, development and productivity of various varieties of winter wheat. Wheat occupies a special place among grain crops in terms of nutritional value and yield. It is known that Uzbekistan, winter wheat is saturated with a vital factor - light. On average, 2,500-3,000 hours of sunshine per year fall on the soil of our country. Therefore, in agriculture, it is possible to determine the sowing time, which corresponds to the biological properties of winter wheat. Wheat bread is superior to other products in its deliciousness, nutritional value and ease of digestion.
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Johansson, Eva, Petter Oscarson e Tomas Lundborg. "Effect of planting date on flowering time in wheat". Physiologia Plantarum 96, n. 2 (febbraio 1996): 338–41. http://dx.doi.org/10.1034/j.1399-3054.1996.960226.x.
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Johansson, Eva, Petter Oscarson e Tomas Lundborg. "Effect of planting date on flowering time in wheat". Physiologia Plantarum 96, n. 2 (febbraio 1996): 338–41. http://dx.doi.org/10.1111/j.1399-3054.1996.tb00223.x.
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Drost, D. T., e H. C. Price. "Stand Establishment of Fluid-drilled Tomato in Rye and Wheat Tillage Systems". HortScience 26, n. 12 (dicembre 1991): 1475–78. http://dx.doi.org/10.21273/hortsci.26.12.1475.
Testo completoAbstract (sommario):
Tomatoes (Lycopersicon esculentum Mill.) were grown in conventional tillage (CT), rye (Secale cereale L.) mulch no tillage (RNT), and wheat (Triticum aestivum L.) mulch no tillage (WNT). Either germinated seeds (GS) or raw seeds (RS) were fluid drilled on several dates in 1981 and 1982. Tomato stands in no tillage (NT) generally were equal to or higher than in CT, and stands improved with later plantings in each year. Plant stands were unaffected by GS and RS. Time to 50% emergence (T50) was up to 4 days less in NT than in CT and 2 to 3 days less from GS than RS. Yields with CT were twice as high as those with NT for early planting dates. Yields decreased in CT with successive planting dates to levels equal to NT plantings. Use of GS increased fruit yields as compared to RS, regardless of the planting date.
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Li, Q. Q., X. B. Zhou, Y. H. Chen e S. L. Yu. "Grain yield and quality of winter wheat in different planting patterns under deficit irrigation regimes". Plant, Soil and Environment 56, No. 10 (20 ottobre 2010): 482–87. http://dx.doi.org/10.17221/14/2010-pse.
Testo completoAbstract (sommario):
Limited water resources restrict winter wheat grain yield and quality in the Huang-Huai-Hai Plain of North China, and establishing optimal planting patterns according to crop water requirements is the key factor for achieving rational water use. In this paper, 4 planting patterns were applied, namely, uniform row (30 cm; traditional pattern), wide (40 cm)-narrow (20 cm) row, furrow (double lines in the furrow with 20 cm spacing, and 40 cm between furrows), and seed bed (double lines on the bed with 20 cm spacing, and 40 cm between beds). Each planting pattern was irrigated twice during the jointing and heading stages, and total irrigation water was controlled at 120 mm. Grain yield was significantly (LSD, P < 0.05) higher in the furrow planting pattern than in the uniform row, wide-narrow row, and seed bed planting patterns, by 73.4, 64.3, and 53.4 g/m<sup>2</sup>, respectively, in 2004–2005 and by 54.3, 42.6, and 30.2 g/m<sup>2</sup>, respectively, in 2005–2006, mainly because of a significant (LSD, P < 0.05) increase in the spike and kernel numbers. These results were caused by changes in the contribution of dry matter remobilization to grain yield (CDMRG); the CDMRG was higher in the furrow planting pattern than in the uniform row, wide-narrow row, and seed bed planting patterns by 5.1%, 4.3%, and 2.9%, respectively. Gliadin and glutenin contents in the furrow planting pattern were 4.67% and 5.85%, respectively, and were significantly (LSD, P < 0.05) higher than those in the uniform row, wide-narrow row, and seed bed planting patterns; however, the furrow planting pattern had no significant (LSD, P < 0.05) effect on albumin and globulin contents. Dough development time (DDT) and dough stable time (DST) in the furrow planting pattern were 5.6 min and 8.8 min, respectively; they were significantly (LSD, P < 0.05) improved compared to those in the uniform row, wide-narrow row, and seed bed planting patterns; however, there were no significant (LSD, P < 0.05) differences in dough breakdown time (DBT) between any of the planting patterns. These results suggest that the furrow planting pattern combined with deficit irrigation during the jointing and heading stages can be applied to winter wheat production in the Huang-Huai-Hai Plain of North China.
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Yadav, R. L., Ravi Kumar e R. S. Verma. "Effect of Planting Technique and Planting Density on Yield of Late Planted Sugarcane in North Central India". Experimental Agriculture 27, n. 3 (luglio 1991): 281–86. http://dx.doi.org/10.1017/s0014479700019001.
Testo completoAbstract (sommario):
SummaryIn the wheat–sugarcane rotation, which covers more than half of the growing area in subtropical India, planting of sugarcane is delayed until after the wheat harvest in April–May. This allows little time for the sugarcane to produce tillers and so results in smaller millable cane populations and yields than those from more timely (February–March) plantings. This study considers techniques such as ring and trench planting which might allow a high seed rate to compensate for reduced tillering. Yields obtained using these systems were about 20 t ha−1 greater than from the conventional flat planting method, because of a better distribution of primary shoots from the parent sett and reduced plant competition during the early stage of growth. The cost of cane production was greatest with the ring system and least with the conventional planting method but deep trenches gave the best net return.
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Zhang, Wenmin, Martin Brandt, Alexander V. Prishchepov, Zhaofu Li, Chunguang Lyu e Rasmus Fensholt. "Mapping the Dynamics of Winter Wheat in the North China Plain from Dense Landsat Time Series (1999 to 2019)". Remote Sensing 13, n. 6 (19 marzo 2021): 1170. http://dx.doi.org/10.3390/rs13061170.
Testo completoAbstract (sommario):
Monitoring spatio-temporal changes in winter wheat planting areas is of high importance for the evaluation of food security. This is particularly the case in China, having the world’s largest population and experiencing rapid urban expansion, concurrently, it puts high pressure on food demands and the availability of arable land. The relatively high spatial resolution of Landsat is required to resolve the historical mapping of smallholder wheat fields in China. However, accurate Landsat-based mapping of winter wheat planting dynamics over recent decades have not been conducted for China, or anywhere else globally. Based on all available Landsat TM/ETM+/OLI images (~28,826 tiles) using Google Earth Engine (GEE) cloud computing and a Random Forest machine-learning classifier, we analyzed spatio-temporal dynamics in winter wheat planting areas during 1999–2019 in the North China Plain (NCP). We applied a median value of 30-day sliding windows to fill in potential data gaps in the available Landsat images, and six EVI-based phenological features were then extracted to discriminate winter wheat from other land cover types. Reference data for training and validation were extracted from high-resolution imagery available via Google Earth™ online mapping service, Sentinel-2 and Landsat imagery. We ran a sensitivity analysis to derive the optimal training sample class ratio (β = 1.8) accounting for the unbalanced distribution of land-cover types. We mapped winter wheat planting areas for 1999–2019 with overall accuracies ranging from 82% to 99% and the user’s/producer’s accuracies of winter wheat range between 90% and 99%. We observed an overall increase in winter wheat planting areas of 1.42 × 106 ha in the NCP as compared to the year 2000, with a significant increase in the Shandong and Hebei provinces (p < 0.05). This result contrasts the general discourse suggesting a decline in croplands (e.g., rapid urbanization) and climate change-induced unfavorable cropping conditions in the NCP. This suggests adjustments of the winter wheat planting area over time to satisfy wheat supply in relation to food security. This study highlights the application of Landsat images through GEE in documenting spatio-temporal dynamics of winter wheat planting areas for adequate management of cropping systems and assessing food security in China.
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ARORA, V. K., A. S. SIDHU, K. S. SANDHU e S. S. THIND. "EFFECTS OF TILLAGE INTENSITY, PLANTING TIME AND NITROGEN RATE ON WHEAT YIELD FOLLOWING RICE". Experimental Agriculture 46, n. 3 (28 maggio 2010): 267–75. http://dx.doi.org/10.1017/s0014479710000311.
Testo completoAbstract (sommario):
SUMMARYPuddling coarse-textured soils for rice culture in the irrigated tract of the Indo-Gangetic Plains causes high soil strength in the upper layers. This may adversely affect growth and yield of following upland crops. It is possible that no-tillage (NT) in wheat (without residues of preceding rice crop) could aggravate this problem and reduce fertilizer nitrogen (N) use efficiency. In certain production scenarios, NT has been reported to be advantageous because it allows for earlier planting of wheat by eliminating delays caused by tillage. This study examined the combined effects of two crop establishment options for wheat in relation to fertilizer N and planting time following puddled rice cultivation in an irrigated environment of Punjab, northwest India. Combinations of two establishment systems, NT-direct planting and conventional-tillage (CT) with soil disruption to 0.10 m depth in main plots, with two N rates, 120 and 150 kg ha−1 in subplots, were evaluated. Variation in planting time, 31 October (D1) and 7 and 10 November (D2), was used to evaluate effect of planting-earliness. Under D1 in NT, grain yield of wheat was comparable to that under D2 in CT. However, under no advancement of wheat planting in NT, grain yield was 0.2–0.3 t ha−1 less than that in CT. This yield reduction in NT could be overcome by adding 30 kg ha−1 more fertilizer N suggesting that tillage enhanced N use efficiency. These tillage gains are ascribed to the greater extraction of profile stored and applied water and nutrients because of denser crop rooting caused by reduction in soil strength and less weed competition. Higher N use efficiency in CT suggests that farmers could achieve fertilizer N savings with this system. Comparing the tillage systems showed that NT was more cost-effective than CT even after accounting for the cost of additional fertilizer N (saving of Rs. 1685 ha−1) to overcome associated yield penalties under no advancement in planting time.
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Green, C. F., e J. D. Ivins. "Time of sowing and the yield of winter wheat". Journal of Agricultural Science 104, n. 1 (febbraio 1985): 235–38. http://dx.doi.org/10.1017/s0021859600043185.
Testo completoAbstract (sommario):
Research conducted on sowing dates for wheat shows a trend towards increased yield as sowing is advanced (U.K.: Walker, 1980; Bingham et al. 1983; the Netherlands: Darwinkel, Hag & Kuizenga, 1977; Canada: Nass et al.1975; Briggs & Aytenfisu, 1979). In a review of the influence of drilling time on winter wheat in the U.K. McLean (1981) suggested October planting as the optimum. However, sowing before this time often results in increased yield (Bingham et al.1983).
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Elmiati, Reni, Zulfadly Syarif e Auzar Syarif. "PRODUKTIVITAS GANDUM (Triticum aestivum L.) DAN CAISIM (Brassica rapa L.) PADA SISTEM TUMPANGSARI". Jurnal BiBieT 3, n. 1 (21 novembre 2018): 1. http://dx.doi.org/10.22216/jbbt.v3i1.2215.
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<p>Penelitian tumpangsari gandum/caisim bertujuan untuk mengetahui pengaruh jarak tanam gandum (<em>Triticum aestivum L</em>.) dan waktu penanaman caisim (<em>Brassica rapa L</em>.) terhadap produktivitas gandum dan caisim. Caisim ditanam satu baris diantara dua baris gandum. Sebagai pembanding terhadap hasil, ditanam gandum dan caisim secara tunggal. Percobaan menggunakan rancangan acak kelompok (RAK) faktorial dengan 3 ulangan. Perlakuan meliputi jarak tanam gandum 20cm x 25cm, 25cm x 25cm dan 30cm x 25cm dan waktu tanam caisim 9 minggu setelah tanam gandum (MSTg), 10 MSTg dan 11 MSTg. Penelitian ini dilakukan di lahan penelitian BPTP Sumatera Barat, Arosuka dan Laboratorium Fisiologi Tanaman, Universitas Andalas, Padang. Hasil penelitian menunjukkan jarak tanam gandum dan waktu tanam caisim belum memberikan pengaruh terhadap pertumbuhan dan hasil tanaman gandum dan caisim. Untuk Land Equivalent Rasio (LER) dan Area Time Equivalent Ratio (ATER) menunjukkan sistem tumpangsari gandum/caisim lebih menguntungkan dibandingkan penanaman secara monokultur dengan diperolehnya nilai LER dan ATER >1, sedangkan dari perhitungan Nisbah Kompetisi (NK) tanaman gandum dan caisim diperoleh gandum merupakan komponen dominan dalam sistem tumpangari gandum/caisim.</p><p> </p><p>The research of intercropping wheat/caisim aims to determine the effect of plant spacing of wheat (<em>Triticum aestivum L.</em>) and time planting of caisim (<em>Brassica rapa L.</em>) on the productivity of wheat and caisim. Caisim planted a row between two rows of what. As a comparison of the results and wheat or caisim planted single. Experiment using a randomized block design (RAK) factorial with 3 replications. Treatment includes seed spacing 20cm x 25cm, 25cm x 25cm and 30cm x 25cm and planting time of caisim 9 weeks after planting wheat (MSTg), 10 MSTg and 11 MSTg. The research was conducted in BPTP trials field West Sumatera, Arosuka and Plant Physiology Laboratory, Andalas University in Padang. The result showed seed spacing and time of planting caisim not have any impact on the growth and yield of wheat and caisim. For the Land Equivalent Ratio (LER) and Area Time Equivalent Ratio (ATER) showed wheat cropping system/caisim more profitable than planting in monoculture with LER values obtained and ater > 1, while the Ratio of Competition (NK) wheat crop and wheat gained caisim is the dominant component in the intercropping system wheat/caisim.</p>
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Green, C. F., G. A. Paulson e J. D. Ivins. "Time of sowing and the development of winter wheat". Journal of Agricultural Science 105, n. 1 (agosto 1985): 217–21. http://dx.doi.org/10.1017/s0021859600055921.
Testo completoAbstract (sommario):
Research conducted on sowing dates has shown a trend towards increased yield as sowing is advanced for winter wheat (Darwinkel, Hay & Kuizenga, 1977; Walker, 1980) and winter barley (Selman, 1980; White, 1981). Green & Ivins (1985) have quantified the rate of yield decline for winter wheat as sowing is delayed after mid-September, giving a mean value of 0–35% per day. For a similar study on winter barley (Green, Furmston & Ivins, 1985) a yield decline of 0–43% per day delay in sowing was attributed to reductions in the number of ears per unit area as planting was delayed.
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Li, Fangjie, Jianqiang Ren, Shangrong Wu, Hongwei Zhao e Ningdan Zhang. "Comparison of Regional Winter Wheat Mapping Results from Different Similarity Measurement Indicators of NDVI Time Series and Their Optimized Thresholds". Remote Sensing 13, n. 6 (18 marzo 2021): 1162. http://dx.doi.org/10.3390/rs13061162.
Testo completoAbstract (sommario):
Generally, there is an inconsistency between the total regional crop area that was obtained from remote sensing technology and the official statistical data on crop areas. When performing scale conversion and data aggregation of remote sensing-based crop mapping results from different administrative scales, it is difficult to obtain accurate crop planting area that match crop area statistics well at the corresponding administrative level. This problem affects the application of remote sensing-based crop mapping results. In order to solve the above problem, taking Fucheng County of Hebei Province in the Huanghuaihai Plain of China as the study area, based on the Sentinel-2 normalized difference vegetation index (NDVI) time series data covering the whole winter wheat growth period, the statistical data of the regional winter wheat planting area were regarded as reference for the winter wheat planting area extracted by remote sensing, and a new method for winter wheat mapping that is based on similarity measurement indicators and their threshold optimizations (WWM-SMITO) was proposed with the support of the shuffled complex evolution-University of Arizona (SCE-UA) global optimization algorithm. The accuracy of the regional winter wheat mapping results was verified, and accuracy comparisons with different similarity indicators were carried out. The results showed that the total area accuracy of the winter wheat area extraction by the proposed method reached over 99.99%, which achieved a consistency that was between the regional remote sensing-based winter wheat planting area and the statistical data on the winter wheat planting area. The crop recognition accuracy also reached a high level, which showed that the proposed method was effective and feasible. Moreover, in the accuracy comparison of crop mapping results based on six different similarity indicators, the winter wheat distribution that was extracted by root mean square error (RMSE) had the best recognition accuracy, and the overall accuracy and kappa coefficient were 94.5% and 0.8894, respectively. The overall accuracies of winter wheat that were extracted by similarity indicators, such as Euclidean distance (ED), Manhattan distance (MD), spectral angle mapping (SAM), and spectral correlation coefficient (SCC) were 94.1%, 93.9%, 93.3%, and 92.8%, respectively, and the kappa coefficients were 0.8815, 0.8776, 0.8657, and 0.8558, respectively. The accuracy of the winter wheat results extracted by the similarity indicator of dynamic time warping (DTW) was relatively low. The results of this paper could provide guidance and serve as a reference for the selection of similarity indicators in crop distribution extraction and for obtaining large-scale, long-term, and high-precision remote sensing-based information on a regional crop spatial distribution that is highly consistent with statistical crop area data.
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Song, Yang, e Jing Wang. "Mapping Winter Wheat Planting Area and Monitoring Its Phenology Using Sentinel-1 Backscatter Time Series". Remote Sensing 11, n. 4 (21 febbraio 2019): 449. http://dx.doi.org/10.3390/rs11040449.
Testo completoAbstract (sommario):
Crop planting area mapping and phenology monitoring are of great importance to analyzing the impacts of climate change on agricultural production. In this study, crop planting area and phenology were identified based on Sentinel-1 backscatter time series in the test region of the North China Plain, East Asia, which has a stable cropping pattern and similar phenological stages across the region. Ground phenological observations acquired from a typical agro-meteorological station were used as a priori knowledge. A parallelepiped classifier processed VH (vertical transmitting, horizontal receiving) and VV (vertical transmitting, vertical receiving) backscatter signals in order to map the winter wheat planting area. An accuracy assessment showed that the total classification accuracy reached 84% and the Kappa coefficient was 0.77. Both the difference ( σ d ) between VH and VV and its slope were obtained to contrast with a priori knowledge and then used to extract the phenological metrics. Our findings from the analysis of the time series showed that the seedling, tillering, overwintering, jointing, and heading of winter wheat may be closely related to σ d and its slope. Overall, this study presents a generalizable methodology for mapping the winter wheat planting area and monitoring phenology using Sentinel-1 backscatter time series, especially in areas lacking optical remote sensing data. Our results suggest that the main change in Sentinel-1 backscatter is dominated by the vegetation canopy structure, which is different from the established methods using optical remote sensing data, and it is available for phenological metrics extraction.
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Farooq, Omer, Muqarrab Ali, Muhammad Naeem, Abdul Sattar, Muhammad Ijaz, Ahmad Sher, Tauqeer Ahmad Yasir e Muhammad Mazhar Iqbal. "IMPACT OF SOWING TIME AND PLANTING METHOD ON THE QUALITY TRAITS OF WHEAT". Journal of Global Innovations in Agricultural and Social Sciences 3, n. 1 (1 marzo 2015): 08–11. http://dx.doi.org/10.17957/jgiass/3.1.676.
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Chen, Shi, Lingling Fan, Shefang Liang, Hao Chen, Xiao Sun, Yanan Hu, Zhenhuan Liu, Jing Sun e Peng Yang. "Spatiotemporal Dynamics of the Northern Limit of Winter Wheat in China Using MODIS Time Series Images". Remote Sensing 12, n. 15 (24 luglio 2020): 2382. http://dx.doi.org/10.3390/rs12152382.
Testo completoAbstract (sommario):
Studying the spatiotemporal changes of the northern limit of winter wheat (NLWW) in China is important to ensure regional food security and deal with the effects of climate change. Previous studies mainly used climate indicators to analyze the variation of the potential NLWW in different historical periods, while little attention has been paid to the actual migrations and changes of the NLWW. The objectives of the present study were three-fold: (i) to map the spatial distribution of winter wheat in northern China in 2001, 2007, 2014 and 2019; (ii) to extract the actual NLWW; and (iii) to quantitatively explore the dynamics of the NLWW. First, we adopted the “combining variations before and after estimated heading dates” method to map the winter wheat in northern China based on time series MODIS EVI2 data. Second, we used the kernel density estimation algorithm to extract the actual NLWW in four historical periods. Finally, the fishnet method was utilized to quantitatively analyze the direction and distance of the spatiotemporal changes of the NLWW. The results demonstrated that the NLWW has exhibited a marked fluctuating trend of migration southward, with a 37-km shift in latitude over the past 20 years. The elevation limit of winter wheat planting was around 1600 m; however, the centroid of winter wheat planting has shifted slowly to lower elevations. There was a gap between the actual NLWW and the potential NLWW. The reason for this gap was that the actual NLWW moved southward under the interacting effects of human activities and climate change, while the potential NLWW moved northward due to climate change. The results of this study are of great scientific value in the formulation of winter wheat planting strategies in climate-sensitive areas to respond to climate change and ensure food security.
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Nie, Hanjiang, Tianling Qin, Hanbo Yang, Juan Chen, Shan He, Zhenyu Lv e Zhenqian Shen. "Trend Analysis of Temperature and Precipitation Extremes during Winter Wheat Growth Period in the Major Winter Wheat Planting Area of China". Atmosphere 10, n. 5 (1 maggio 2019): 240. http://dx.doi.org/10.3390/atmos10050240.
Testo completoAbstract (sommario):
In this study, the major winter wheat planting area of China is selected as the study area, with the time scale of the growth period of winter wheat (a total of 56 growth periods during October 1961 to May 2016). The significance, stability, magnitude of the trend and the average trend of the study area with eight temperature indices and seven precipitation indices of 453 meteorological stations are tested by Mann–Kendall method and Sen’s nonparametric method. The following observation can be made: (1) the cold extreme indices show strong and stable downward trend in most of the stations in the study area, while the hot extreme indices show a strong and stable upward trend, especially in the northern winter wheat planting area and the north of the southern winter wheat planting area. (2) The trends of extreme precipitation indices in most of the sites in the study area are insignificant and unstable. Only in R20mm, a significant and stable decreasing trend is shown in some stations, which is mainly located in the northern winter wheat planting area and part of the central and western regions in the study area. The results in some ways could enrich the references for understanding the climate change in the growth period of winter wheat in the region and help to formulate a better agronomic management practice of winter wheat.
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Kerr, NJ, KHM Siddique e RJ Delane. "Early sowing with wheat cultivars of suitable maturity increases grain yield of spring wheat in a short season environment". Australian Journal of Experimental Agriculture 32, n. 6 (1992): 717. http://dx.doi.org/10.1071/ea9920717.
Testo completoAbstract (sommario):
Eleven field trials were sown in the northeastern wheatbelt of Western Australia to test the hypothesis that if wheat cultivars with suitable maturity are sown earlier than current practice, then higher grain yields will be achieved. The experiments included time of sowing treatments that ranged from early May to late June in 1988, 1989 and 1990. Seven commercial cultivars with a wide range of developmental patterns and maturities were used. Sowing between mid May and early June produced the highest grain yields. For plantings after early June, yields declined by approximately 250 kg/ha (15%) per week. Delayed sowing caused a decrease in dry matter and kernel number (per m2). In general this reduction in kernel number was not compensated by an improvement in kernel weight. At early times of sowing, the medium-long season cultivars generally had higher yields than short season cultivars. The short season cultivars were the highest yielding cultivars at the late times of sowing. These results suggest that cultivars should be chosen to suit the seasonal break, which may vary from late April to mid June. As a consequence, farmers should be encouraged to retain a number of cultivars with differing maturities suited to a range of planting times.
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Donald, William W., e Tony Prato. "Profitable, Effective Herbicides for Planting-Time Weed Control in No-till Spring Wheat (Triticum aestivum)". Weed Science 39, n. 1 (marzo 1991): 83–90. http://dx.doi.org/10.1017/s0043174500057921.
Testo completoAbstract (sommario):
High herbicide costs and uncertainty about annual weed control at planting have limited adoption of no-till spring wheat production systems in the northern Great Plains. Chlorsulfuron, metsulfuron, and CGA-131036 at 10 to 20 g ai ha–1plus nonionic surfactant generally controlled both emerged kochia and wild mustard equally well (>80%) whether or not combined with glyphosate at 250 g ha–1plus nonionic surfactant. In two of three trials persistent phytotoxic residues of these sulfonylurea herbicides in soil controlled both weeds better in midseason and early summer 1 yr after treatment than did glyphosate, which has only foliar activity. While the absolute net returns of different treatments varied among herbicides, relative net returns were insensitive to changes in either herbicide or wheat price. Herbicide use tended to boost net returns for no-till spring wheat in years with good weather but depressed net returns in a drought year. Chlorsulfuron at 10 and 20 g ha–1increased net returns in all three trials. Metsulfuron and combinations of either metsulfuron or chlorsulfuron with glyphosate had variable effects on net returns.
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Woodruff, DR. "'WHEATMAN' a decision support system for wheat management in subtropical Australia". Australian Journal of Agricultural Research 43, n. 7 (1992): 1483. http://dx.doi.org/10.1071/ar9921483.
Testo completoAbstract (sommario):
This paper presents the basic relationships used in compiling a decision support system for wheat growers in the subtropical, prime-hard regions of Australia. The major factors addressed by this decision aid are climate variability, soil type and water status; N and P soil status and fertilizer addition; variety phenology, planting time and frost risk; weed infestation. The major decisions involved include fertilizer choice and quantity, choice of the variety development pattern to use for a given planting opportunity, and wild oat control measures. It demonstrates how the output from relatively complex, dynamic wheat models can be used at the farm level by introducing a number of factors (nitrogen status, frost risk, soil water status at planting, grain yield and protein records) measurable and specific to a given farm and/or paddock. The importance of such local measurements, and the consequent tailoring of the output to the user's conditions, on the user's confidence in, and ownership of, the final decision is demonstrated.
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Kuznetsova, Yu A., A. I. Bozhkov e N. G. Menzyanova. "Planting density and culture time of wheat seedlings affect their growth rate and exometabolite production". Indian Journal of Plant Physiology 23, n. 3 (settembre 2018): 557–63. http://dx.doi.org/10.1007/s40502-018-0385-5.
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Thomas, J. A., G. L. Hein e D. J. Lyon. "Spread of Wheat Curl Mite and Wheat Streak Mosaic Virus is Influenced by Volunteer Wheat Control Methods". Plant Health Progress 5, n. 1 (gennaio 2004): 2. http://dx.doi.org/10.1094/php-2004-1206-01-rs.
Testo completoAbstract (sommario):
Wheat streak mosaic virus is the most damaging disease in winter wheat in the western Great Plains. The wheat curl mite is the vector of this virus and utilizes volunteer wheat as a “green bridge” to over-summer and re-infest fall planted winter wheat. This study demonstrates the effect of tillage and glyphosate control of volunteer wheat on mite movement and subsequent virus infection. Small mite populations (1 to 2 mites per tiller) caused high infection rates in winter wheat. Both tillage and glyphosate were effective at reducing mite populations on volunteer wheat, but tillage resulted in more rapid reduction of mite populations. If volunteer wheat is to be controlled close to planting time, tillage is the best choice for rapid control of mite populations when warm dry weather conditions exist. Accepted for publication 21 October 2004. Published 6 December 2004.
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John, Freeha, Noor Abid Saeed, Sajid Nadeem e Muhammad Hamed. "Integration of Planting Time and Insecticide to Manage Aphid Infestations in Wheat for Better Crop Productivity". Pakistan Journal of Zoology 49, n. 4 (luglio 2017): 1343–51. http://dx.doi.org/10.17582/journal.pjz/2017.49.4.1343.1351.
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Hoque, M. A., e M. R. Karim. "Upscaling and Evaluation of BARI Inclined Plate Planter". Agriculturists 13, n. 2 (30 gennaio 2016): 1–8. http://dx.doi.org/10.3329/agric.v13i2.26582.
Testo completoAbstract (sommario):
The BARI inclined plate planter was developed for one pass tillage and seeding operation. But the planter was not capable of planting small seeds as seeds were entering between the plate and base. So, six additional MS base plates were incorporated in the planter. Three plates were redesigned and fabricated for maize seed (9 cells); for wheat, mungbean, lentil, jute, etc (32 cells) and for rice seed (11 cells). Changing of inclination of the plate is needed to use same (32 seed cell) plates for different crops and to calibrate the planter for 10% more or less seed than the predefined rates. Field test of BARI developed inclined plate planter was conducted in Gazipur, Pabna, and Barisal and its performance were evaluated. The planter was tested for sowing maize, wheat and mungbean during 2011-12. Effective field capacity and field efficiency were 0.17 ha/h and 75%, respectively. Coefficient of seed distribution uniformity and coefficient of planting depth uniformity were 97 and 94%, respectively. Time and cost saving to complete land preparation and planting of maize by inclined plate planter were 90 and 86%, respectively than conventional hand planting. The payback period of the BARI planter is 1.20 year. Break-even use time is 97 hours.The Agriculturists 2015; 13(2) 01-08
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Mkhabela, Manasah, Guy Ash, Mike Grenier e Paul Bullock. "Testing the suitability of thermal time models for forecasting spring wheat phenological development in western Canada". Canadian Journal of Plant Science 96, n. 5 (1 ottobre 2016): 765–75. http://dx.doi.org/10.1139/cjps-2015-0351.
Testo completoAbstract (sommario):
Predicting crop development stages is fundamental to many aspects of agronomy (e.g., pesticides and fertilizer applications). Temperature is the main factor affecting plant development and its impact on crop development is often measured using thermal-time. We compared different thermal-time models to identify the best model for simulating spring wheat development in western Canada. Models compared include (i) North-Dakota growing-degree-day (NDGDD), (ii) growing-degree-day base-temperature zero (GDD0), (iii) growing-degree-day base-temperature five (GDD5), (iv) beta-function (BF), and (v) modified-beta-function (MBF). We utilised agro-meteorological data collected across western Canada from 2009–2011. Results showed that accumulated heat units/daily growth rates from the different models correlated well with spring wheat phenology with R2 ≥ 0.91 and P < 0.001. However, when the developed models were used to predict time (calendar-days) from planting to anthesis for cultivar AC-Barrie, the BF and MBF models performed poorly. Average predicted times from planting to anthesis by NDGDD, GDD0, GDD5, BF, and MBF models were 63, 63, 62, 65, and 64 d, respectively; while the actual observed time was 60 d. Root-mean-square error (RMSE) for NDGDD was 4 d, 5 d for GDD0 and GDD5, and 6 d for BF and MBF. These findings suggest that simple GDD-based models performed better than more complex BF-based models.
25
Zhang, Dongyan, Shengmei Fang, Bao She, Huihui Zhang, Ning Jin, Haoming Xia, Yuying Yang e Yang Ding. "Winter Wheat Mapping Based on Sentinel-2 Data in Heterogeneous Planting Conditions". Remote Sensing 11, n. 22 (13 novembre 2019): 2647. http://dx.doi.org/10.3390/rs11222647.
Testo completoAbstract (sommario):
Monitoring and mapping the spatial distribution of winter wheat accurately is important for crop management, damage assessment and yield prediction. In this study, northern and central Anhui province were selected as study areas, and Sentinel-2 imagery was employed to map winter wheat distribution and the results were verified with Planet imagery in the 2017–2018 growing season. The Sentinel-2 imagery at the heading stage was identified as the optimum period for winter wheat area extraction after analyzing the images from different growth stages using the Jeffries–Matusita distance method. Therefore, ten spectral bands, seven vegetation indices (VI), water index and building index generated from the image at the heading stage were used to classify winter wheat areas by a random forest (RF) algorithm. The result showed that the accuracy was from 93% to 97%, with a Kappa above 0.82 and a percentage error lower than 5% in northern Anhui, and an accuracy of about 80% with Kappa ranging from 0.70 to 0.78 and a percentage error of about 20% in central Anhui. Northern Anhui has a large planting scale of winter wheat and flat terrain while central Anhui grows relatively small winter wheat areas and a high degree of surface fragmentation, which makes the extraction effect in central Anhui inferior to that in northern Anhui. Further, an optimum subset data was obtained from VIs, water index, building index and spectral bands using an RF algorithm. The result of using the optimum subset data showed a high accuracy of classification with a great advantage in data volume and processing time. This study provides a perspective for winter wheat mapping under various climatic and complicated land surface conditions and is of great significance for crop monitoring and agricultural decision-making.
26
Dong, Qi, Xuehong Chen, Jin Chen, Chishan Zhang, Licong Liu, Xin Cao, Yunze Zang, Xiufang Zhu e Xihong Cui. "Mapping Winter Wheat in North China Using Sentinel 2A/B Data: A Method Based on Phenology-Time Weighted Dynamic Time Warping". Remote Sensing 12, n. 8 (17 aprile 2020): 1274. http://dx.doi.org/10.3390/rs12081274.
Testo completoAbstract (sommario):
Accurate mapping of winter wheat over a large area is of great significance for guiding policy formulation related to food security, farmland management, and the international food trade. Due to the complex phenological features of winter wheat, the cloud contamination in time-series imagery, and the influence of the soil/snow background on vegetation indices, there remains no effective method for mapping winter wheat at a medium spatial resolution (10–30 m). In this study, we proposed a novel method called phenology-time weighted dynamic time warping (PT-DTW) for identifying winter wheat based on Sentinel 2A/B time-series data. The main advantages of PT-DTW include (1) the use of phenological features in two periods, i.e., the greenness increase before winter and greenness decrease after heading, which are common to all winter wheat and are distinct from the features of other land cover types, and (2) the use of the normalized differential phenology index (NDPI) instead of traditional vegetation indices to provide more robust vegetation information and to suppress the adverse impacts of soil and snow cover, especially during the before-winter growth period. The proposed PT-DTW method was employed for winter wheat mapping based on Sentinel 2A/B data on the Huang-Huai Plain, China. Validation with visually interpreted samples showed that the produced winter wheat map achieved an overall classification accuracy of 89.98% and a kappa coefficient of 0.7978, outperforming previous winter wheat classification methods. Moreover, the planting area derived from PT-DTW agreed well with census data at the municipal level, with a coefficient of determination of 0.8638, indicating that the winter wheat map produced at 20 m resolution was reliable overall. Therefore, the PT-DTW method is recommended for winter wheat mapping over large areas.
27
Pu, Liu, Li, Chen, Liu, Qi, Wei e Zheng. "Planting Locations with Higher Temperature Produce More Bioactive Compounds and Antioxidant Capacities of Wheat". Agronomy 9, n. 9 (11 settembre 2019): 538. http://dx.doi.org/10.3390/agronomy9090538.
Testo completoAbstract (sommario):
Bioactive compounds such as phenols and phytic acid in wheat contribute to antioxidant capacities. (1) Background: Prior studies drew a general conclusion that the environment affected bioactive compounds greatly, but how the single environmental factor affects these characteristics remains unclear. (2) Methods: We conducted that twenty-eight winter wheat genotypes were grown in replicated trials at seven locations in China for two consecutive years and subdivided the environmental factor into five soil factors and six meteorological factors to evaluate the impact on the antioxidant capabilities and bioactive compounds contents of wheat grains by using principal component analysis (PCA). RT-PCR was used to identify gene expression of bioactive compounds under different conditions. (3) Results: Temperature affects bioactive compounds contents and antioxidant capacities greatly in wheat grains. Accumulation time, daylight length, and daily maximum temperature showed a high correlation with bioactive compounds contents and antioxidant capacities, especially in the vegetative growth phase. The gene TaMIPs related to phytic acid and TaPAL1, TaC3H1, TaC4H, Ta4CL1, and TaCOMT1 related to total phenolics had higher gene expression level with larger temperature differences in wheat grains. (4) Conclusions: The planting locations with higher temperatures and longer daylight length could produce higher contents of bioactive compounds and antioxidant capacities and the cooler temperatures of a planting location might produce wheat grains with lower phytic acid contents in wheat grains.
28
Davidson, JL, KR Christian, DB Jones e PM Bremner. "Responses of wheat to vernalization and photoperiod". Australian Journal of Agricultural Research 36, n. 3 (1985): 347. http://dx.doi.org/10.1071/ar9850347.
Testo completoAbstract (sommario):
The effects of vernalization and photoperiod on times from planting of seedlings to ear emergence were measured in 68 Australian and 49 overseas varieties of wheat, comprising a broad spectrum of genetic material, in a glasshouse in Canberra (latitude 35�S). Vernalization was carried out by growing germinated seedlings in the dark at 1-2�C for 6 weeks. Long photoperiods (16 h) separated unvernalized plants into two distinct groups, corresponding to commonly recognized spring and winter types. Responses to vernalization were generally small under natural photoperiods (11-15 h), but much more pronounced in long photoperiods, particularly with winter wheats. In a second experiment, 24 varieties of wheat gave widely different responses to vernalization treatments. With 8 weeks' vernalization and long photoperiods, all varieties reached ear emergence within 66 days, but in some winter wheats 4 weeks treatment had little effect and 6 weeks gave incomplete vernalization. Under the conditions of these experiments, Australian wheats showed a wide range of responses to photoperiod and a narrow range of responses to vernalization compared with overseas varieties. The need to investigate the control of flowering time in obtaining varieties suited to the high-rainfall zone of Australia is discussed.
29
Attia, M. B., A. I. Farag, Saadeia M. Saed e Nehal O. Swelam. "EFFECT OF PLANTING TIME AND STORAGE METHODS ON GRAIN WEEVILS, SITOPHILUS SPP (COLEOPTERA: CURCULIONIDAE) INFESTING WHEAT GRAINS". Menoufia Journal of Plant Protection 2, n. 2 (1 aprile 2017): 101–9. http://dx.doi.org/10.21608/mjapam.2017.125606.
Testo completo
30
KUCEY, R. M. N. "THE INFLUENCE OF RATE AND TIME OF MINERAL N APPLICATION ON YIELD AND N2 FIXATION BY FIELD BEAN". Canadian Journal of Plant Science 69, n. 2 (1 aprile 1989): 427–36. http://dx.doi.org/10.4141/cjps89-054.
Testo completoAbstract (sommario):
Greenhouse experiments were conducted to determine the effect of rate and timing of nitrogen (N) fertilizer on growth, N uptake and N2 fixation by nodulated field beans (Phaseolus vulgaris L. ’GN1140’). Fertilizer N was added at 30, 60 or 120 mg kg−1 soil either at planting or at 2, 4, 6, 8 or 10 wk after planting. N2 fixation was determined by using 15N isotope dilution methods with spring wheat (Triticum aestivum ’Leader’) as a nonfixing control plant. Additions of N at 30 mg kg−1 soil had a stimulatory effect on plant growth, relative to plants not receiving N fertilizer, which was reflected in increased N uptake and N2 fixation. Addition of N at 60 or 120 mg kg−1 soil did not result in increased plant N uptake and was shown to inhibit N2 fixation. Stimulatory effects of 30 mg N, and inhibitory effects of 60 or 120 mg N, were only observed if N additions were made within the first 6 wk after planting. Additions of N after that time did not affect the plant parameters measured in this study. It was concluded that additions of N at rates of 60 or 120 mg kg−1 do not result in increased plant growth because of the resulting decreases in the contribution of biologically fixed N2 to plant N uptake. It was also concluded that once the N2-fixing symbioses with GN1140 was established, biological N2 fixation was able to supply sufficient N for the plant needs.Key words: 15N dilution, starter N, field bean, N2 fixation, N addition, wheat, Rhizobium phaseoli
31
Eversmeyer, M. G., e C. L. Kramer. "Models of Early Spring Survival of Wheat Leaf Rust in the Central Great Plains". Plant Disease 82, n. 9 (settembre 1998): 987–91. http://dx.doi.org/10.1094/pdis.1998.82.9.987.
Testo completoAbstract (sommario):
Severe leaf rust epidemics, which result in economic yield reductions in the Great Plains wheat-producing region of the United States, are usually initiated by Puccinia recondita f. sp. tritici inoculum that has survived in the local field from the previous wheat crop until early spring. Models were developed for an epidemic year beginning at physiological maturity of one wheat crop to maturity of the following wheat crop. Meteorological variables for periods prior to final tiller development of the wheat crop during 1980 to 1992 at several sites in the central Great Plains winter-wheat-production area were used to model inoculum survival from one wheat crop until early spring of the next crop. Stepwise multiple regression was used to identify weather variables that explained the most variation in inoculum survival at the final tiller development wheat growth stage. Inoculum survival was recorded on a 0 to 9 scale with 0 indicating no survival and 9 indicating inoculum on all wheat plants in the field. Independent variables used in development of models were daily deviations from the 10-year average of maximum and minimum temperature, fungal temperature equivalence function, cumulative fungal temperature function, precipitation, cumulative precipitation, and snow cover averaged for 10-day periods prior to dates inoculum forecasts were desired. Models were constructed to forecast inoculum survival from data collected prior to fall wheat planting, the beginning of winter dormancy of the wheat, and the final tiller development wheat growth stage. Of the observed occurrences of leaf rust overwintering, 70% were forecast by models constructed using weather data prior to wheat planting decision time. Overwintering could be forecast by models constructed with data prior to the wheat entering winter dormancy 80% of the time. Models constructed with data collected prior to final tiller development in the spring forecast overwintering of leaf rust inoculum 95% of the time. Results from these models will be used to develop forecasts of leaf rust epidemics and resulting yield reductions.
32
Kieckhefer, R. W., N. C. Elliott, W. E. Riedell e B. W. Fuller. "YIELD OF SPRING WHEAT IN RELATION TO LEVEL OF INFESTATION BY GREENBUGS (HOMOPTERA: APHIDIDAE)". Canadian Entomologist 126, n. 1 (febbraio 1994): 61–66. http://dx.doi.org/10.4039/ent12661-1.
Testo completoAbstract (sommario):
AbstractThe effect of greenbug, Schizaphis graminum (Rondani), infestations on yield components of early- and late-planted spring wheat, Triticum aestivum L., were measured in 2 successive years in eastern South Dakota. Greenbug populations in plots generally increased rapidly and peaked when wheat plants were in boot stage. Populations then began a steady decrease until anthesis, at which time they were near zero. The number of seeds per spikelet and the number of spikelets per square metre were consistently significantly negatively correlated with aphid-days, whereas average seed weight was significantly negatively correlated with aphid-days for only one planting. A linear regression model that included different intercepts for each spring wheat planting and a common slope relating yield to greenbug feeding days (aphid-days) provided a good fit to the data. Based on the model, a loss of 41 kg of grain per hectare is expected for each 100 aphid-days that accumulate per tiller.
33
Anderson, Randy L. "Timing of Nitrogen Application Affects Downy Brome (Bromus tectorum) Growth in Winter Wheat". Weed Technology 5, n. 3 (settembre 1991): 582–85. http://dx.doi.org/10.1017/s0890037x00027378.
Testo completoAbstract (sommario):
Field studies were conducted to determine if varying the time N fertilizer was applied would affect downy brome interference in winter wheat. Five treatments were compared: four broadcast application times of NH4NO3at 56 kg N ha-1during the fallow-crop cycle: 1) during fallow; 2) at planting; 3) during crop dormancy; 4) before winter wheat jointing; and 5) a control where no N was applied. Downy brome was least responsive to N applied during fallow. All N applications during the growing season of winter wheat increased downy brome biomass and culms m-2. Downy brome interference prevented winter wheat from responding positively to N. For example, when crop season precipitation was only 70% of normal, applying N reduced grain yield of winter wheat infested with downy brome from 12 to 28%. This study indicates that N manipulation offers potential for reducing downy brome interference in winter wheat.
34
Klemm, Toni, e Renee A. McPherson. "Assessing Decision Timing and Seasonal Climate Forecast Needs of Winter Wheat Producers in the South-Central United States". Journal of Applied Meteorology and Climatology 57, n. 9 (settembre 2018): 2129–40. http://dx.doi.org/10.1175/jamc-d-17-0246.1.
Testo completoAbstract (sommario):
AbstractAgricultural decision-making that adapts to climate variability is essential to global food security. Crop production can be severely impacted by drought, flood, and heat, as seen in recent years in parts of the United States. Seasonal climate forecasts can help producers reduce crop losses, but many nationwide, publicly available seasonal forecasts currently lack relevance for agricultural producers, in part because they do not reflect their decision needs. This study examines the seasonal forecast needs of winter wheat producers in the southern Great Plains to understand what climate information is most useful and what lead times are most relevant for decision-making. An online survey of 119 agricultural advisers, cooperative extension agents in Oklahoma, Kansas, Texas, and Colorado, was conducted and gave insights into producers’ preferences for forecast elements, what weather and climate extremes have the most impact on decision-making, and the decision timing of major farm practices. The survey participants indicated that winter wheat growers were interested not only in directly modeled variables, such as total monthly rainfall, but also in derived elements, such as consecutive number of dry days. Moreover, these agricultural advisers perceived that winter wheat producers needed seasonal climate forecasts to have a lead time of 0–2.5 months—the planning lead time for major farm practices, like planting or harvesting. A forecast calendar and monthly rankings for forecast elements were created that can guide forecasters and advisers as they develop decision tools for winter wheat producers and that can serve as a template for other time-sensitive decision tools developed for stakeholder communities.
35
BUTTAR, G. S., H. S. SIDHU, VICKY SINGH, M. L. JAT, R. GUPTA, YADVINDER SINGH e BALDEV SINGH. "RELAY PLANTING OF WHEAT IN COTTON: AN INNOVATIVE TECHNOLOGY FOR ENHANCING PRODUCTIVITY AND PROFITABILITY OF WHEAT IN COTTON–WHEAT PRODUCTION SYSTEM OF SOUTH ASIA". Experimental Agriculture 49, n. 1 (12 dicembre 2012): 19–30. http://dx.doi.org/10.1017/s0014479712001032.
Testo completoAbstract (sommario):
SUMMARYCotton–wheat (CW) is the second most important cropping system after rice–wheat in South Asia. Sowing of wheat after cotton is usually delayed due to late pickings coupled with time needed for seedbed preparation, resulting in low wheat yield. Lack of suitable machinery is a major constraint to direct drilling of wheat into the heavy cotton stubbles. An innovative approach with much promise is the ‘2-wheel tractor-based self-propelled relay seeder’ with seed-cum-fertilizer attachment. On-farm trials were conducted at four locations during 2009–2010 and at 10 locations during 2010–2011 to evaluate the following four wheat establishment methods in CW-dominated areas of south-western Punjab, India: (1) zero till seeding in standing cotton using a self-propelled relay seeder, (2) relay seeding in standing cotton with a manual drill without prior tillage (2010 only), (3) relay broadcast seeding in standing cotton following light manual tillage and (4) conventional sowing of wheat after cotton harvest (conventional tillage and sowing with a seed–fertilizer drill). Planting of wheat under conventional practice was delayed by 20–44 days compared with relay seeding. Seed cotton yield was also significantly higher with relay seeding due to opportunity for one additional picking. Yield of wheat sown with the self-propelled relay seeder was 41.2% and 11.8% higher than with conventional practice in 2009–2010 and 2010–2011 respectively. The increase in wheat yield under relay seeding of wheat was primarily due to higher spike density and more grains per spike. The net income from the CW system was 28.2% higher for the self-propelled relay seeder than with conventional sowing.
36
Anderson, R. L. "Cultural Systems Can Reduce Reproductive Potential of Winter Annual Grasses". Weed Technology 11, n. 3 (settembre 1997): 608–13. http://dx.doi.org/10.1017/s0890037x00045504.
Testo completoAbstract (sommario):
Feral rye and jointed goatgrass are winter annual grasses that infest winter wheat in the western United States. Currently, no herbicides are available that selectively control these weeds in wheat. Because of this constraint, producers need cultural practices that reduce the seed densities of these two grasses in the soil seedbank. This research shows that applying nitrogen 5 mo before wheat planting and increasing the seeding rate with a tall wheat cultivar reduces seed production per plant of either species by > 40%. However, tall wheat cultivars usually yield less grain than semidwarf cultivars. Producers can avoid this yield loss by combining narrow rows with time of N application and increased seeding rate of semidwarf cultivars. This combination reduces weed seed production similarly to cultural systems with tall cultivars.
37
Schlatter, Daniel C., Ian Burke e Timothy C. Paulitz. "Succession of Fungal and Oomycete Communities in Glyphosate-Killed Wheat Roots". Phytopathology® 108, n. 5 (maggio 2018): 582–94. http://dx.doi.org/10.1094/phyto-06-17-0212-r.
Testo completoAbstract (sommario):
The successional dynamics of root-colonizing microbes are hypothesized to be critical to displacing fungal pathogens that can proliferate after the use of some herbicides. Applications of glyphosate in particular, which compromises the plant defense system by interfering with the production of aromatic amino acids, are thought to promote a buildup of root pathogens and can result in a “greenbridge” between weeds or volunteers and crop hosts. By planting 2 to 3 weeks after spraying, growers can avoid most negative impacts of the greenbridge by allowing pathogen populations to decline, but with the added cost of delayed planting dates. However, the specific changes in microbial communities during this period of root death and the microbial taxa likely to be involved in displacing pathogens are poorly characterized. Using high-throughput sequencing, we characterized fungal and oomycete communities in roots after applications of herbicides with different modes of action (glyphosate or clethodim) and tracked their dynamics over 3 weeks in both naturally infested soil and soil inoculated with Rhizoctonia solani AG-8. We found that many unexpected taxa were present at high relative abundance (e.g., Pythium volutum and Myrmecridium species) in live and dying wheat roots and may play an under-recognized role in greenbridge dynamics. Moreover, communities were highly dynamic over time and had herbicide-specific successional patterns, but became relatively stable by 2 weeks after herbicide application. Network analysis of communities over time revealed patterns of interactions among taxa that were both common and unique to each herbicide treatment and identified two primary groups of taxa with many positive associations within-groups but negative associations between-groups, suggesting that these groups are antagonistic to one another in dying roots and may play a role in displacing pathogen populations during greenbridge dynamics.
38
SINGH, YADVINDER, e E. G. BEAUCHAMP. "RESPONSE OF WINTER WHEAT TO FALL-APPLIED LARGE UREA GRANULES WITH DICYANDIAMIDE". Canadian Journal of Soil Science 68, n. 1 (1 febbraio 1988): 133–42. http://dx.doi.org/10.4141/cjss88-012.
Testo completoAbstract (sommario):
Three field experiments were undertaken over a 2-yr period to compare the response of winter wheat to fall-applied large urea granules containing a nitrification inhibitor (dicyandiamide, DCD) with that of commercial urea granules (prills) applied as a top dressing in the spring. The objective was to determine the effectiveness of large urea granules coupled with DCD in conserving N when applied at planting or one month after planting. Granules of 1, 2 and 3 g urea as well as 2 g urea + DCD were compared with commercial urea prills at an application rate of 80 kg N ha−1. Large urea granules, as compared with fall-incorporated commercial urea prills, were effective in conserving N over the winter period especially when applied 1 mo after planting and resulted in yields and apparent N recovery similar to those with top dressed commercial prills applied in the spring. Incorporation of DCD into 2-g granules (50 or 100 g kg−1 urea) further increased the conservation of N fertilizer as reflected by higher yields and greater apparent fertilizer N recovery. Uptake of 15N from 2-g urea granules decreased with distance from the granule. However, plants furthest from spaced large granules were able apparently to obtain sufficient N to reach the yield potential dictated by the weather and soil conditions. Yield and N recovery data indicated that N conservation increased with increasing granule size. Crop response and fertilizer N availability decreased as depth of placement exceeded 10 cm. Placement between the 5 and 10 cm depths appeared to maximize fertilizer N availability. It was concluded that a combination of large urea granules and a nitrification inhibitor (such as DCD) can effectively conserve fall-applied N and result in yield responses and N uptake by winter wheat similar to that with commercial urea prills applied as a top dressing in the spring. Key words: Time of application, yield, 15N recovery, apparent fertilizer N recovery
39
Batbold, S. "Grain quality of spring wheat varieties". Mongolian Journal of Agricultural Sciences 17, n. 1 (3 gennaio 2017): 15–20. http://dx.doi.org/10.5564/mjas.v17i1.721.
Testo completoAbstract (sommario):
Spring wheat is main crop of Mongolia and sown more 90% of agricultural planting area. Total wheat production of Mongolia are increasing gradually, but out of strong and valuable wheat for bread and flour production. Main case of providing sustainable wheat production are develop and widely cultivate strong and valuable wheat varieties resistant to abiotic stresses, with high yield and good quality. Spring wheat varieties by HMW-GS loci were similar, but variety Darkhan-166 /Arvin/ was more than others varieties. Wheat varieties Darkhan-144, KP-547-12, Darkhan-131, Darkhan-144 and KP-561-12 have a high 1000 grain weight (41.5-44.8 g). Spring wheat varieties KP-547-12, Darkhan-131 and KP-561-12 have a high dry gluten content (13.1-14.2%). Water absorption of spring wheat varieties were 61-62% and by this parameters Darkhan-131, Darkhan-166 and KP-547-12 varieties were a high. Dough development time of wheat varieties were 8-13 мин and Darkhan-131, Darkhan-166, Darkhan-172 and KP-547-12 varieties have a high flour power. Wheat varieties Darkhan-131 and KP-547-12 have a high dough energy (828.8-857.2 g.mm).
40
Hossain, Md Israil, MK Gathala, TP Tiwari e M. Jahedul Islam. "Development of cost effective small No-till seeder for two wheel tractor in Bangladesh". Bangladesh Journal of Agricultural Research 42, n. 1 (29 marzo 2017): 27–34. http://dx.doi.org/10.3329/bjar.v42i1.31970.
Testo completoAbstract (sommario):
Two wheel tractor (Power tiller) is the common means of soil tillage and other farm operations in Bangladesh due to easy access in fragmented land size with affordable price. A low cost and small robust 2WT driven (12 hp) No-till seeder has been developed with press wheel attachment and inclined plate seed meter assembly in Farm Machinery & Postharvest Process Engineering Division, BARI, Bangladesh for seeding different kinds of seeds. This is a pull type implement hitched at drawbar point of 2WT replacing the regular rotary part. The developed No-till seeder was used in the farmers field of Rajshahi areas for wheat, maize, pulses, and rice establishment during the year 2011-2014. The planter can pull 4 tynes in soft and medium hard soil but 3 tynes for hard soil. The planter was capable to apply seed and fertilizer in the furrows. The width and depth of the furrow opening were 30 mm and 60 mm, respectively. The planting depth, row spacing and seed rate can be adjusted according to standard practices. The No-till seeder works effectively through high density crop residue (1.5-2.4 t/ha) without any problem as there are sufficient residue clearances between toolbar and ground surface. Depending on the level of weed situation, round up herbicide was applied 2 days before of planting. There were significant yield difference in wheat, pulses but rice yield was lower than conventional transplanting method. No-till planted crops show less lodging tendency compare to conventional planted crops. There were significant cost differences between no-till and conventional method. The planting costs of wheat and maize in Notill system were 60% and 86% less than conventional planting method. It also reduces the average turn around time 7-9 days between the two crops. The effective area coverage by the seeder was 0.13ha/hr. The No-till seeder is a low cost (US$ 350-400; without power unit), light in weight and local manufacturer can fabricate complete unit within a short period of time. The No-till seeder can be used in other countries where 2WT is the common farming equipment.Bangladesh J. Agril. Res. 42(1): 27-34, March 2017
41
Redden, R. "The effect of epistasis on chromosome mapping of quantitative characters in wheat. I. Time to spike emergence". Australian Journal of Agricultural Research 42, n. 1 (1991): 1. http://dx.doi.org/10.1071/ar9910001.
Testo completoAbstract (sommario):
Chromosome mapping of genes affecting time to spike emergence was attempted using the complete series of donor cultivars Hope, Kenya Farmer and Marquis chromosome substitutions into recipient cultivar Chinese Spring, grown at four locations. Substitution line intercrosses and backcrosses were also grown at two dates of planting at one location. The expression of time to spike emergence involved both additive and between chromosome interaction expressions, which were both strongly affected by location. There was a trend for individual additive effects of chromosomes and for the overall between chromosome interactions in the Hope and Kenya Farmer series to decrease from the early to later winter sowing dates over the four locations. These effects were attributed to interactions between the substituted chromosomes and the background genotype of the recipient variety. A major gene effect accounted for the difference between Marquis and Chinese Spring genotypes, and for certain chromosome expressions in other series.
42
Monterroso-Rivas, Alejandro I., Jesús D. Gómez-Díaz e Antonio R. Arce-Romero. "Soil, Water, and Climate Change Integrated Impact Assessment on Yields". International Journal of Agricultural and Environmental Information Systems 9, n. 2 (aprile 2018): 20–31. http://dx.doi.org/10.4018/ijaeis.2018040102.
Testo completoAbstract (sommario):
This article describes the potential yields of maize, wheat and barley which were modeled with climate change, soil degradation and water balance scenarios in central Mexico. Two adaptation measures were also evaluated. To estimate yields the AquaCrop-FAO model was applied. Three study cases were chosen and their climate, soil, phenological and management information was compiled. Once calibrated, the authors tested the response in yields for 28 climate change scenarios: five General Circulation Models, two RCP and three-time horizons. Two adaptation actions were evaluated: changing planting date and increase of organic mulches. Results show that yield of maize in the near future (2015-2039) would fall 50% average, barley and wheat yields would decrease in 40% and 25% respectively. If soil degradation and loss is considered, the yield will reduce considerably. Adaptation measure based on changing planting date was as effective as increasing mulches. It is necessary to consider soil together with climate change scenarios in yield modeling. It is possible to suggest wrong adaptation measures if only the climate is considered and not all the variables involved.
43
Xu, Feng, Zhaofu Li, Shuyu Zhang, Naitao Huang, Zongyao Quan, Wenmin Zhang, Xiaojun Liu, Xiaosan Jiang, Jianjun Pan e Alexander V. Prishchepov. "Mapping Winter Wheat with Combinations of Temporally Aggregated Sentinel-2 and Landsat-8 Data in Shandong Province, China". Remote Sensing 12, n. 12 (26 giugno 2020): 2065. http://dx.doi.org/10.3390/rs12122065.
Testo completoAbstract (sommario):
Winter wheat is one of the major cereal crops in China. The spatial distribution of winter wheat planting areas is closely related to food security; however, mapping winter wheat with time-series finer spatial resolution satellite images across large areas is challenging. This paper explores the potential of combining temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data available via the Google Earth Engine (GEE) platform for mapping winter wheat in Shandong Province, China. First, six phenological median composites of Landsat-8 OLI and Sentinel-2 MSI reflectance measures were generated by a temporal aggregation technique according to the winter wheat phenological calendar, which covered seedling, tillering, over-wintering, reviving, jointing-heading and maturing phases, respectively. Then, Random Forest (RF) classifier was used to classify multi-temporal composites but also mono-temporal winter wheat development phases and mono-sensor data. The results showed that winter wheat could be classified with an overall accuracy of 93.4% and F1 measure (the harmonic mean of producer’s and user’s accuracy) of 0.97 with temporally aggregated Landsat-8 and Sentinel-2 data were combined. As our results also revealed, it was always good to classify multi-temporal images compared to mono-temporal imagery (the overall accuracy dropped from 93.4% to as low as 76.4%). It was also good to classify Landsat-8 OLI and Sentinel-2 MSI imagery combined instead of classifying them individually. The analysis showed among the mono-temporal winter wheat development phases that the maturing phase’s and reviving phase’s data were more important than the data for other mono-temporal winter wheat development phases. In sum, this study confirmed the importance of using temporally aggregated Landsat-8 OLI and Sentinel-2 MSI data combined and identified key winter wheat development phases for accurate winter wheat classification. These results can be useful to benefit on freely available optical satellite data (Landsat-8 OLI and Sentinel-2 MSI) and prioritize key winter wheat development phases for accurate mapping winter wheat planting areas across China and elsewhere.
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Chen, Yu Lun, Wei Qiu, Wei Min Ding, Yi Nian Li e Yu Tao Liu. "Improvement and Test on Ditcher Chain Transmission System of the Machine for Rice-Wheat Cyclic Planting". Applied Mechanics and Materials 644-650 (settembre 2014): 853–57. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.853.
Testo completoAbstract (sommario):
To solve the problem of irrational assignment on the transmission ratio, redesigned the transmission scheme and optimized the parameters of the rice-wheat cyclic planting machine’s ditcher chain transmission device. Results showed that transmission ratio of the improved system was assigned rationally, all the sprockets not only met the strength requirement, but also had moderate sizes and were easy to be assembled or disassembled, at least 41.57% of the material was saved, not less than 50% of the production cost was reduced; noise level of the optimized chain transmission system was lowered obviously than the original’s at the same rotary speeds all the time, the maximum difference reached 16.8 dB when the driving sprockets rotary speeds of the first-stage chain are 1200 rpm; safety of loading, accessibility to field and flexibility of transfer in field of the machine were improved significantly, such an optimized chain transmission system for ditching was reliable.
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Singh, Samunder, R. K. Malik, R. S. Panwar e R. S. Balyan. "Influence of Sowing Time on Winter Wild Oat (Avena ludoviciana) Control in Wheat (Triticum aestivum) with Isoproturon". Weed Science 43, n. 3 (settembre 1995): 370–74. http://dx.doi.org/10.1017/s0043174500081340.
Testo completoAbstract (sommario):
Field experiments were conducted during the winters of 1987–88 and 1988–89 at Haryana Agricultural University, Hisar, India to evaluate the response of winter wild oat to sowing date and isoproturon application time in wheat. In another experiment, the effect of sowing time on emergence and growth of winter wild oat and wheat sown separately was studied. The treatments that provided more than 75% control of winter wild oat were: isoproturon at 0.75 kg ha−1applied at the 2-leaf stage of winter wild oat; isoproturon 1 kg ha−1applied at the 4-leaf stage of winter wild oat in the November 30 planting; and isoproturon 0.50 kg ha−1applied at the 1- to 2-leaf stage of winter wild oat in the December 20 sowing. Isoproturon did not provide more than 50% control of winter wild oat in the November 10 sowing. Mortality of winter wild oat increased from 38 to 72 to 87% in November 10, November 30, and December 20 sowings, respectively. Mortality of winter wild oat was similar in November 30 and December 20 sowings but higher grain yield was recorded in November 30 sowing. Due to vigorous growth of winter wild oat in the November 10 sowing, isoproturon did not provide good control. December 20 sowing favored wheat growth due to lower density and late emergence of winter wild oat but reduction in wheat grain yield was greater. When averaged over isoproturon treatments, the grain yield of wheat was 4607, 5297, and 4457 kg ha−1in the November 10, November 30, and December 20 sowings, respectively.
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Young, Frank L., Daniel A. Ball, Donn C. Thill, J. Richard Alldredge, Alex G. Ogg e Steven S. Seefeldt. "Integrated Weed Management Systems Identified for Jointed Goatgrass (Aegilops cylindrica) in the Pacific Northwest". Weed Technology 24, n. 4 (dicembre 2010): 430–39. http://dx.doi.org/10.1614/wt-d-10-00046.1.
Testo completoAbstract (sommario):
Jointed goatgrass is an invasive winter annual grass weed that is a particular problem in the low to intermediate rainfall zones of the Pacific Northwest (PNW). For the most part, single-component research has been the focus of previous jointed goatgrass studies. In 1996, an integrated cropping systems study for the management of jointed goatgrass was initiated in Washington, Idaho, and Oregon in the traditional winter wheat (WW)–fallow (F) region of the PNW. The study evaluated eight integrated weed management (IWM) systems that included combinations of either a one-time stubble burn (B) or a no-burn (NB) treatment, a rotation of either WW–F–WW or spring wheat (SW)–F–WW, and either a standard (S) or an integrated (I) practice of planting winter wheat. This study is the first, to our knowledge, to evaluate and identify complete IWM systems for jointed goatgrass control in winter wheat. At the Idaho location, in a very low weed density, no IWM system was identified that consistently had the highest yield, reduced grain dockage, and reduced weed densities. However, successful IWM systems for jointed goatgrass management were identified as weed populations increased. At the Washington location, in a moderate population of jointed goatgrass, the best IWM system based on the above responses was the B:SW–F–WW:S system. At the Washington site, this system was better than the integrated planting system because the competitive winter wheat variety did not perform well in drought conditions during the second year of winter wheat. At the Oregon site, a location with a high weed density, the system B:SW–F–WW:I produced consistently higher grain yields, reduced grain dockage, and reduced jointed goatgrass densities. These integrated systems, if adopted by PNW growers in the wheat–fallow area, would increase farm profits by decreasing dockage, decreasing farm inputs, and reducing herbicide resistance in jointed goatgrass.
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Cudney, David W., Lowell S. Jordan, Chris J. Corbett e Warren E. Bendixen. "Developmental Rates of Wild Oats (Avena fatua) and Wheat (Triticum aestivum)". Weed Science 37, n. 4 (luglio 1989): 521–24. http://dx.doi.org/10.1017/s0043174500072349.
Testo completoAbstract (sommario):
Prediction of the developmental stages of wheat and wild oats would be useful in order to: 1) correctly time the application of herbicides, and 2) accurately schedule research and cultural operations. The Haun developmental scale which numbers leaf development and describes floral development on the main stem of grasses was found to be suitable for describing the development of semidwarf wheat and wild oats in California. Haun developmental rates of wheat and wild oats were similar. Interference by wheat or wild oats in mixed cultures did not change the developmental rate of either species when grown with added nutrients and water. Degree days gave better correlations with development than calendar days when different planting dates, years, and locations were compared. A degree day model with a 5 C base temperature and a second-order polynomial expression gave accurate predictions of developmental stage, which correlated well with field data.
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Ender, Gary, Abdul Wasay e Aklitar Mahmood. "Wheat Price Policies in Pakistan: Should there be a Subsidy?" Pakistan Development Review 31, n. 4II (1 dicembre 1992): 1157–71. http://dx.doi.org/10.30541/v31i4iipp.1157-1171.
Testo completoAbstract (sommario):
In the 1980s, Pakistan's wheat policies taxed its producers and subsidised its consumers. Moreover, the post-rationing, open-ended system of releases has increased the burden on the government budget. The Government now faces severe shortages of resources at a time when human capital and physical infrastructure must be developed and maintained. This paper reviews wheat price policies in Pakistan and,patterns of wheat consumption over time, and makes recommendations for policy changes. Wheat is the dominant rabi, or winter, crop. However, about half the wheat is grown after cotton. Most of this wheat is planted late and yields substantially less than it could if planted earlier because the producer price and profitability of wheat are depressed by government policies. While cotton prices are also depressed by the Government, cotton, and in particular a fourth picking, remains highly profitable, even with new, earlier varieties. CIMMYT studies have shown that wheatcotton farmers are rational in planting wheat late, given the prices they receive. 1 The average wheat yield has risen since the Green Revolution, due to the adoption of HYVs. However, the yields of HYVs have not risen, After they harvest their wheat, farmers can sell it to the Government (namely to the Pakistan Agricultural Storage and Services Corporation (PASS CD) or the provincial food departments) at the procurement price, or to a private trader at the market price. Thus two prices prevail in the market at any given time. Wheat moves through both channels primarily because of differences in quality.
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Anosov, S. I., A. S. Surnachev e K. K. Musinov. "Sugar accumulation in winter wheat crops depending on the sowing dates". Siberian Herald of Agricultural Science 49, n. 2 (22 maggio 2019): 27–33. http://dx.doi.org/10.26898/0370-8799-2019-2-3.
Testo completoAbstract (sommario):
The object of the research was to study the influence of sowing dates on sugar accumulation in different varieties of soft winter wheat. Less winterhardy variety of soft winter wheat Novosibirskaya 2 was compared with more winter-hardy ones Novosibirskaya 3, Novosibirskaya 40 and Krasnoobskaya ozimaya. The research was carried out in 2016-2018 inthe established experimental plot in the foreststeppe of Priobye, theObregion. The predecessor was bare fallow. The planting dates were August 20, September 1, September 10. Weather conditions of the autumn growing season, during which the accumulation of sugars occurs, differed significantly depending on the year of study and the sowing dates. The warmest conditions were in 2018, whereas the coolest – in 2017. The amount of accumulated sugars varied depending on the growing conditions and genotypic characteristics of varieties. The highest amount of sugars was accumulated by all varieties during the third term of planting, the lowest amount – during the second term. Lower air temperatures contributed to the increase in the amount of sugars, even when the duration of their accumulation period was shortened, which can be explained by a change in carbohydrate balance in crops when the accumulation of sugars is greater than their consumption for crop respiration. The genotype plays an important role in the carbohydrate metabolism of plants. In more winter-hardy varieties (Novosibirskaya 40, Novosibirskaya 3), the change in the amount of accumulated sugars in contrasting conditions ranged insignificantly (the coefficient of variation was 9.1 and 8.7%, respectively). At the same time, plants of the less winter-hardy variety of Novosibirskaya 2 showed a significantly greater variation in the sugar content under similar conditions (the coefficient of variation 24.7%). Cooler conditions of a later term of sowing contributed to the greatest amount of accumulated sugars. Varietal differences also determined changes in carbohydrate balance.
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Laskowska, Halina, Elżbieta Pogroszewska, Wojciech Durlak e Danuta Kozak. "The effect of bulb planting time and type of mulch on the yield of Allium aflatunense B. Fedtsch." Acta Agrobotanica 65, n. 4 (2012): 117–22. http://dx.doi.org/10.5586/aa.2012.028.
Testo completoAbstract (sommario):
The aim of the study was to determine the effect of bulb planting time and the type of mulch on the morphological traits of plants and on bulb yield of <em>Allium aflatunense </em>B. Fedtsch. 'Purple Sensation'. Bulbs of 12 cm diameter were used as the study material. The bulbs were planted in plots on three dates: September 15th, October 1st, and October 15th. The plantation was mulched after frost with two types of mulch: composted pine bark and wheat straw. Phenological phases of the plants were observed during the growing season. At the full flowering stage, several observations and measurements were taken: length of leaves, length of inflorescence peduncle, peduncle diameter, inflorescence diameter, and number of flowers per inflorescence. After harvest, total numerical and weight yield of bulbs were evaluated as well as number and weight of the largest bulbs (21–22 cm diameter). The study showed that in order to obtain <em>Allium aflatunense </em>of high ornamental value, which is determined by the number of flowers per inflorescence and the inflorescence peduncle diameter, bulbs need to be planted in the middle of September. Bulb planting in October leads to production of inflorescences of greater diameter. The optimum method of <em>Allium aflatunense </em>cultivation which ensures production of good total yield of bulbs, expressed in its weight, is bulb planting on September 15th and soil mulching with composted pine bark or straw. Mulching a plantation of <em>Allium aflatunense </em>planted on September 15th with bark has a positive effect on the number and weight of bulbs of 21–22 cm diameter.