Winter Wheat Harvest Research Articles

The influence of weather conditions on the formation of the winter wheat harvest according to various precursors in the arid zone of Stavropol

Relevance. The identification of agro meteorological factors that have the greatest impact on the formation of grain yields and their consideration in the improvement of agricultural technologies is an urgent task of agriculture.Methods. The research was carried out in 1972–2023 in the fields of the Prikumsk experimental breeding station in a 6-pole grain-and-grass crop rotation. The purpose of the research is to study the influence of agro meteorological conditions on the formation of the winter wheat harvest according to various precursors for the correction and adaptation of applied agricultural technologies in the arid zone of the Stavropol Territory.Results. The yield of winter wheat significantly depended on precipitation in September — October, moisture reserves by spring, total moisture availability of crops, temperature in May and was determined by the density of plants and the weight of 1000 grains. The maximum yield was formed with precipitation in September — October >117 mm, the highest density of standing (294–392 pcs/m2), spring moisture reserves in the meter soil layer and average total moisture supply for pure steam, respectively, 129–145 mm and 382 mm, occupied steam 115–135 mm and 378 mm and winter wheat 105–125 mm and 342 mm. The minimum duration of the sowing — germination period and the maximum density of standing accounted for a clean and occupied pair for the amount of precipitation for September — October (59–87), and a half-pair >117 mm. Compared with pure steam, the density of standing decreased by an average of 12,2%, the yield by 19,2%, the duration of germination increased 1.4 times, and in repeated crops by 22,6%, 45,3% and 2,7 times, respectively. The mass of 1000 grains had a significant positive relationship with the density of standing by half-steam and a negative one with the average temperature for May — June by pure steam. For half-steam and pure steam, yield is more closely related to the mass of 1000 grains (r = 0.52–0.66) than to the density of standing (r = 0.45–0.50).

Effect of Phosphorus and Magnesium Fertilizers on Mineral Nutrition and Yield of Winter Wheat depending on Liming of Sod-Podzolic Soil

In long-term field experience on strongly acidic, poorly cultivated sod-podzolic soil, high efficiency of phosphorus fertilizers combined with magnesium and liming in the cultivation of winter wheat of the Moskovskaya 56 variety was revealed. Under these conditions, the content of nitrogen, phosphorus and magnesium in plants in the flowering phase increased. Improving the mineral nutrition of plants in this case provided the highest yield (75.3 c/ha), exceeding the background level of nitrogen-potassium fertilizers by 2.7 times, the payback of mineral fertilizers (NPK) increased by 2.5 times, reaching 16.7 kg/kg. The use of phosphorus fertilizers on highly acidic soil increased yields by 65% at 27.5 c/ha against the background of nitrogen-potassium fertilizers. On calcified soil with a slightly acidic reaction of the medium, the yield from the use of phosphorus fertilizers increased by 19% compared to the background of 58.1 kg/ha. Yield increases when using magnesium fertilizers against the background of full fertilizer (NPK) decreased as soil acidity decreased and were significant: on medium acidic soil – 4.9 and slightly acidic – 6.1 c/ha. At the maximum yield of winter wheat, due to the use of phosphorus and magnesium fertilizers and a decrease in the acidity of sod-podzolic soil, the removal of nutrients by the winter wheat harvest increased: nitrogen – by 3.5, phosphorus – 3.7, potassium and magnesium – 3 times.

Profitability of foliar fungicides in double crop soybean under low-disease environments

Double-crop soybean production involves planting soybean (Glycine max) directly following winter wheat (Triticum aestivum) harvest. Frogeye leaf spot (FLS), caused by Cercospora sojina, is an important late-season foliar disease affecting soybean fields in the United States. In some instances, foliar fungicides have been used in double-crop soybean production with little to no FLS present, raising questions on the profitability of these applications. This study analyzed yield data from 25 fungicide trials across five states (Illinois, Indiana, Kentucky, Missouri, and Tennessee) conducted under low FLS pressure, from 2008 to 2021, on double-crop soybean. Fungicide classes evaluated in the trials included quinone outside inhibitors (QoI), demethylation inhibitors (DMI), and methyl benzimidazole carbamates (MBC) applied alone, and mixtures of chemistry classes that included DMI+succinate dehydrogenase inhibitor (SDHI), MBC+DMI, QoI+DMI, and QoI+DMI+SDHI. A network meta-analytic model estimated yield differences between fungicide-treated and nontreated plots, which ranged from -28 to 72 kg/ha among the fungicide treatments. Negative yield response values were estimated for the single fungicide classes MBC (-15.7 kg/ha) and QoI (-28.4 kg/ha). Yield difference as high as 72.8 kg/ha was estimated only for DMI+SDHI. Economic analyses indicated that, due to the lower yield responses, probabilities of breaking even were lower than 50% for all fungicide treatments, regardless of the fungicide cost or soybean sale price. Therefore, the low yield responses associated with foliar fungicides in low-disease environments linked to the higher risk of not offsetting the costs, suggest that growers should consider disease risk prior to making the fungicide application.

An active-optical reflectance sensor in-field testing for the prediction of winter wheat harvest metrics

The ambition of this study was to justify the possibility of wheat trait prediction using NDVI from a newly developed Plant-O-Meter sensor. Acquired data from Plant-O-Meter was matched with GreenSeeker's, which was designated as a reference. The experiment was carried out in the field during the 2022 growing season at the long-term experimental field. The experimental design included five different winter wheat genotypes and 20 different NPK fertilizer treatments. The GreenSeeker sensor always gave out NDVI values that were higher than those of the Plant-O-Meter by, on average, 0.029 (6.36%). The Plant-O-Meter sensor recorded similar NDVI values (94% of the variation is explained, p<0.01). The Plant-O-Meter's NDVIs had a higher CV for different wheat varieties and different sensing dates. For almost all varieties, GreenSeeker exceeded Plant-O-Meter in predicting yields for the early (March 21st) and late (June 6th) growing seasons. NDVIGreenSeeker data improved yield modeling performance by an average of 5.1% when compared to NDVIPlant-O-Meter; in terms of plant height prediction, NDVIGreenSeeker was 3% more accurate than NDVIPlant-O-Meter and no changes in spike length prediction were found. A compact, economical and user-friendly solution, the Plant-O-Meter, is straightforward to use in wheat breeding programs as well as mercantile wheat production.

Role of soil fertility and varieties in increasing the yield of grain crops

A review of publications devoted to the study of the effect of mineral fertilizers on the yield of various varieties of grain crops on various soils is presented. At the same time, special attention is paid to the assessment of the equity participation of various factors in the formation of their productivity. It was found that the greatest contribution to the formation of yield falls on soil fertility, which on sod-podzolic highly cultivated soils amounted to 68–90%, depending on nitrogen doses and varieties, and the share of nitrogen fertilizers varied from 10 to 32%. The coefficient of variation between varieties in terms of yield was in the range of 16–20%. The increase in winter wheat yield from nitrogen application in comparison with the standard Zarya variety ranged from 64 to 146%. In the experiment of VNIPTIHIM, where 33 varieties of winter wheat and 17 varieties of spring barley were tested, the share of the soil fertility factor in the formation of the winter wheat harvest was 81–82, spring barley – 83–89%, the contribution of the variety, respectively, was 6, 13 and 6%. On ordinary chernozem, its participation in the formation of winter wheat yields slightly exceeded the indicators of sod-podzolic soils, as well as the contribution of fertilizers, despite the introduction of higher doses of mineral fertilizers. The variation in yield depending on the variety was 5–6%. In the experiment on leached chernozem, which was characterized by average agrochemical cultivation, the most productive variety of winter wheat showed a yield 2 times less than that of the previously considered varieties.

Экономическое обоснование уборки зерновых культур ранних фаз спелости очесом и приготовления корма из необмолоченного вороха

Abstract. The stripping of grain allows organizing the separate harvesting of grain for feed in early phases and for food purposes in the phase of full ripeness. Purpose. To carry out the economic justification of the technology of harvesting early ripening grains by stripping without threshing and the technology of preparing pelleted fish feed for fish from unthreshed ears and additives. Methods. Economical estimation of the technology of winter wheat harvesting by stripping in early phases of ripeness without threshing and its processing into feed has been carried out by comparing operational and indicated expenses of the total technological operations. Scientific novelty lies in the joint estimation of the economic efficiency of technologies of harvesting and processing of grain crops. Results. The prime cost of harvesting cereals without threshing and separation is 2.65 times lower than that of the harvesting technology with combine threshing and separation. The cost of performing operations under the traditional (from grain) and the new (from ears) technologies of pelleted fish feed production is almost equal. However, the total cost of technological operations of harvesting grain without threshing and preparation of pelleted feed from unthreshed ears using the new technology is 24.3 % lower than that of traditional technology of harvesting with threshing and preparation of feed from grain. The use of non-grain part of ears of early ripeness in the composition of feed will increase the amount of raw material from hectare of sown area by 20–30 %. The proposed technologies is cost-effective and promising for implementation in the agricultural enterprises of southern Russia.

Microbial activity of dark-chestnut soil in winter wheat crops depending on fertiliser application

Preventing soil degradation is an important task of modern agrarian science. Preservation and increase in beneficial soil microflora are a precondition for satisfactory ecological functioning of soil and its fertility. The purpose of this study was to investigate the dynamics of beneficial soil microflora in winter wheat crops under the impact of mineral fertilisers and Agrobacterium radiobacter on the lands of the south of Ukraine. The study was conducted in threefold replication in the conditions of the Kherson region in 2016- 2020 in the experimental fields of the Institute of Climate-Smart Agriculture of the National Academy of Agrarian Sciences of Ukraine. The study used a systematic design, and the following factors were investigated: no fertiliser and Agrobacterium radiobacter; N120P90; N90P60 + Agrobacterium radiobacter; N120P90 + Agrobacterium radiobacter. The study on the microflora composition in the soil layer at 0-30 cm was carried out in the main stages of winter wheat growth and development through the inoculation of nutritious environment. Statistical analysis was performed using the methods of analysis of variance, correlation, and regression analysis. Dynamic changes in the soil biota composition under the influence of the studied factor were established. The slightest response to mineral fertilisers and bacterial preparation application was in ammonifying bacteria, while the strongest response was in cellulosedegrading microorganisms. The winter wheat harvesting revealed a decrease in the number of ammonifying bacteria in the soil, while the number of nitrifying and cellulose-degrading microflora increased significantly. Regression models for the prediction of the number of nitrifying bacteria and cellulose-degrading microorganisms, developed based on experimental data, have great accuracy (the error is 3.78% and 7.79%), and allow determining the adverse effect of phosphorus fertiliser on the microflora of dark-chestnut soil. The study has no analogues in Ukraine and expands theoretical knowledge about the influence of mineral fertilisers and bacterial preparation, containing Agrobacterium radiobacter, on the composition of beneficial microflora of the dark-chestnut soil

Protection of winter wheat from diseases in the zone of unstable humidization of the Stavropol Territory

The study of new seed protectants and fungicides for treating crops, taking into account varieties and predecessors in certain natural and climatic zones, is relevant and of great importance in optimizing the phyto and sanitary condition and increasing the gross harvest of winter wheat in the Stavropol Territory. The purpose of the research was to improve the protection of winter wheat from diseases in the unstable moisture zone of the Stavropol Territory. During the research process, two experiments were carried out: experiment No. 1 “Determination of the eff ectiveness of seed protectants against a complex of harmful pathogens and their eff ect on the biometric parameters of plants and the yield of winter wheat.” The object of research was winter wheat of the variety Yuka winter wheat sown according to its predecessor winter wheat. Experiment No. 2 “Determination of the eff ectiveness of fungicides in the spring tillering phase against a complex of harmful pathogens and their infl uence on the biometric parameters of plants and the yield of winter wheat.” The object of research was winter wheat of the variety Tanya sown according to its predecessor sunfl ower. The best economic indicators were obtained in variants where winter wheat seeds were treated with Baritone, KS and Lamador Pro, KS. Thus, the net profi t from 1 hectare in them amounted to 39 009,7–40 102,9 rubles, the level of profi tability was 124,8–126,4 %, which was 73,8–75,4 abs.% more than in the option with using the drug Dividend Supreme, KS. When using the fungicide Abrusta, KS in winter wheat crops, the best economic indicators were also obtained. The net profi t per 1 hectare in them amounted to 47 711,5 rubles, the level of profi tability was 134,1 %, which was 64,9 abs.% more than in the control.

Influence of nitrogen and mineral fertilizer application on technological quality indicators of winter wheat harvest and grain in repeated soy crop

Influence of nitrogen and mineral fertilizer application on technological quality indicators of winter wheat harvest and grain in repeated soy crop

CO2 Emissions from Soils under Different Tillage Practices and Weather Conditions

CO2 emissions are one of the greenhouse gases that significantly contribute to climate change. The use of reduced soil tillage practices could contribute to the mitigation of CO2 emissions from soils under ongoing climate change conditions. The use of reduced and no-tillage practices in the summer period, the most critical period for CO2 and for water loss from soils, would contribute to the mitigation of CO2 emissions that is required by the European Union. The aim of this research was to contribute to the specification of CO2 emission factors, following different soil tillage practices in the summer period under variations in weather. Gentler tillage practices were defined in terms of reducing CO2 emissions from the soil. This research was carried out as a long-term field experiment. The effects of soil tillage practices on CO2 emissions were studied over a six-year period as a long-term field experiment and concerned the use of different soil tillage practices for over 20 years (established in 1995), with these including conventional tillage (CT; plowing to 20–22 cm), reduced tillage (RT; chiseling to 10 cm), and no-tillage (NT; without tillage). The crop rotation was winter wheat–winter oilseed rape–winter wheat–pea. CO2 emissions were measured at least 7–10 times during the summer–autumn period in the years 2017–2022 after agrotechnical operations following the winter wheat harvest. Soil moisture was determined in all the treatments. Weather conditions were measured by means of the meteorological station of the Crop Research Institute. The CO2 emissions were the highest in the summer period under CT in comparison with RT and NT. Reduced tillage and no-tillage practices, with mulch on the surface of the soil, decreased CO2 emissions by a 6-year average of 45% and 51%, respectively. The mean CO2 emissions were 6.1, 3.1, and 2.9 μmol CO2 m−2 s−1 for CT, RT, and NT. The highest CO2 emissions and the largest differences among different tillage practices were measured in 2019, with high temperatures and repeated rainfall. CO2 emissions under CT reached 22 μmol CO2 m−2 s−1, which was 7.5 and 5.8 times higher than under RT and NT, respectively. Current weather conditions, mainly temperature and precipitation, played an important role in CO2 emissions. The hot and dry weather in 2018 decreased overall CO2 emissions, with CO2 emissions, even under conventional tillage, reaching only 2.5 μmol CO2 m−2 s−1 on average. As a result of climate change, the temperatures also gradually increased in the later stages of the year, with more summer days being expected during autumn and higher CO2 emissions from soils being expected as a result.

Evaluation of Phytotoxicity of Common Chernozem in the Application of Bacillus sp. and Biochar for Stimulation of Decomposition of Winter Wheat Harvest Residues (Triticum aestivum L.)

Evaluation of Phytotoxicity of Common Chernozem in the Application of Bacillus sp. and Biochar for Stimulation of Decomposition of Winter Wheat Harvest Residues (Triticum aestivum L.)

Reserves of productive water in the soil for growing winter wheat

An analysis of the productive water reserves in the soil at the time of sowing and harvesting of winter wheat cultivated after different preceding crops was carried out. The worst conditions for the water accumulation in the 0–30 cm, 0–50 cm, and 0–100 cm soil layers were created after pea for grain — 5.3 mm, 8.7 mm, and 21.6 mm, respectively, in the soil layers; after soybean — 6.0 mm, 11.7 mm and 28.1 mm, respectively; corn for silage — 4.5 mm, 7.4 mm and 13.3 mm, respectively. Earthing the rye and oat mix and green manure made it possible to accumulate 32.9 mm and 29.9 mm of productive water reserve in the 0–100 cm layer, which can be explained by the earlier clearance of the field before the time of sowing winter wheat. In the link of crop rotation with bare fallow, the reserve of productive water in the 0–100 cm soil layer were the highest and amounted to 74.4 mm, which exceeded the link with corn for silage 5.6 times, with pea for grain and perennial grasses 2.6 and 3.4 times. In the link with soybean, the reserve of productive water in the 0–100 cm soil layer amounted to 28.1 mm, which can be explained by the low yield of this crop in this zone. It should also be taken into account that of all the studied preceding crops, soybean is harvested the latest; therefore, it is not always possible to prepare the soil well for sowing winter wheat. During the period of harvesting winter wheat, the reserve of productive water in the soil depended less on preceding crop. At the same time, in the 0–100 cm soil layer, the highest reserves of productive water were formed in the of crop rotation links with bare fallow — 41.1 mm, perennial grasses — 33.6 mm, vetch and oat mix for green manure and green fodder — 29.3 and 31.4 mm, respectively; the lowest — in the links with pea for grain, soybean and corn for silage: 26.5, 26.9, and 24.9 mm, respectively. The yield of winter wheat in the link with bare fallow was 6.52 t/ha, which by 0.80–0.99 t/ha exceeded the other links of crop rotation.

The effect of injury on the sowing seed qualities of winter bread wheat varieties during harvesting and post-harvest processing

The current paper has presented the study results for the period of 2020–2022 to determine the effect of injury on the quality indicators of seed material in primary seed production of winter wheat varieties (‘Stanichnaya’, ‘Etyud’, Asket, ‘Lidiya’ and ‘Ambar’) during harvesting and post-harvest processing of seeds. There has been established that at different stages of technology in agricultural machines and grain cleaning equipment, during grain production, there was damage to the seed material. There have been identified certain types of injuries that most significantly worsen the sowing quality of seeds and reduce winter wheat productivity. The purpose of the study was to estimate the sowing seed qualities of winter bread wheat varieties of different maturity groups developed by the FSBSI «ARC «Donskoy» depending on their injury by the combine harvester and grain cleaning machines in the primary stages of seed production. The estimation of the quality of winter wheat seed material was carried out on the material obtained during winter wheat harvesting, such as manual threshing (control), threshing with the combine ‘Wintersteiger Classic’, after seed cleaning and sorting equipment VIM-1 «Selection» and Petkus K-531 «Gigant». When harvesting with the combine ‘Wintersteiger Classic’, two threshing modes were used: 1) recommended – 1500 rpm-1; 2) with a reduced speed of the threshing drum – 1000 rpm-1. There has been found that the highest level of seed injury was observed when threshing with a grain harvester (33–54 %). There has been determined that, depending on the type of the trial, the germination energy indicators varied from 89 to 98 %, and laboratory germination from 94 to 99 %. Caryopsis with damage in the embryo area had a high germination rate in laboratory conditions. With an increase in microtraumas, field germination has decreased by 4–17 % compared to the control. The maximum injury and reduction in field germination of seeds was observed in the varieties of the early maturing group. Post-harvest processing of seeds has led to an increase in the percentage of their injury by 1–6 %, regardless of the type of equipment used.

Long-Term Cover Cropping Suppresses Foliar and Fruit Disease in Processing Tomatoes.

While links between soil and plant health are implied, there are few opportunities to empirically evaluate this due to inherent differences among sites. An exception is a long-term experiment established in 2007 (repeated in 2008) in Ridgetown, ON, where improved soil health scores and changes in soil microbial communities were observed in the medium-term with annual cover crops (CC). This led us to hypothesize that CC-induced changes in soil health might affect bacterial spot (Xanthomonas hordorum pv. gardneri) and anthracnose (Colletotrichum coccodes) development in processing tomato. Five CC treatments (no CC control, winter cereal rye, oat, radish, and mix of radish + rye) planted after winter wheat harvest were evaluated in 2019 and 2020 (CC grown nine times over 12 years). Fruit yields and net revenue were similar or greater with CC than without. In 2019, there was greater defoliation (area under the disease progress stairs = 4,370 ± 204), percent red fruit (71.0% ± 5.38), and rots (1.91% ± 0.5) in no CC than with radish (3,410, 39.1%, and 0.62%, respectively, P ≤ 0.0366), indicating earlier fruit maturity in no CC plots. Similarly, no CC had a greater incidence of red fruits with anthracnose (25.8% ± 2.89) compared with all CCs but rye (7.4 to 12.1% ± 2.89; P = 0.0029). Environmental conditions in 2020 were less favourable for disease development. Defoliation was not affected by CC treatment (P = 0.1254), and anthracnose incidence was low (≥90.3 ± 1.22% healthy fruit), which may have limited the ability to detect treatment effects (P = 0.2922). Long-term cover crops have the potential to produce greater or equivalent tomato yield with decreased defoliation and anthracnose fruit rot.

Soil Aggregates Stability Response to Summer Fallow Tillage in Rainfed Winter Wheat Fields on the Loess Plateau

Soil aggregates are one of the most important indicators of soil quality, which can be affected strongly by soil tillage. Little is known about the composition and stability of soil aggregates under summer fallow tillage in rainfed winter wheat fields on the Loess Plateau. Soil aggregates were assessed before sowing and after the harvest of winter wheat under three tillage treatments during summer fallow, including minimum tillage (FMT), subsoiling (FST) and plough tillage (FPT). The results showed that the 0.25–2 mm soil mechanical-stable aggregates (MSA) under the FPT treatment were significantly higher (25.5–42.1%) compared with the FMT treatment in the 0–40 cm soil layer before sowing. The FMT treatment significantly increased the 0.5–2 mm size WSA content (24.6–342.4%) compared with the FPT treatment in the 0–20 cm soil layer before sowing and after harvesting. Compared with the FMT treatment, the FPT treatment significantly increased the stability of the MSA in the 0–20 cm soil layer before sowing and the FST treatment significantly increased the stability of the MSA in the 0–50 cm soil layer after harvest. The FPT treatment significantly decreased the geometric mean diameter (4.2–9.3%) and the stability rate (73.6–252.6%) and increased the destruction rate (1.3–3.5%) and the unstable aggregate index of the WSA (0.8–2.3%) in the 0–20 cm soil layer before sowing, compared with the FMT treatment. In summary, the application of FPT and FST increased the stability of the MSA in the 0–20 cm soil layer; however, FMT improved the stability of the WSA in the 0–40 cm soil layer.

Assessing Impacts of Flood and Drought over the Punjab Region of Pakistan Using Multi-Satellite Data Products

The Punjab region of Pakistan faced significant losses from flash flooding in 2010 and experienced a multiyear drought during 1998–2002. The current study illustrates the drought and flood conditions using the multi-satellite data products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and Tropical Rainfall Measuring Mission (TRMM) as well as the TRMM Multi-satellite Precipitation Analysis (TMPA) satellites with high-quality resolution in the region of Punjab during 2010–2014. To determine the drought and flood events, we used the Vegetation Temperature Condition Index (VTCI) drought monitoring approach combined with the Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) to identify the warm and cold edges (WACE) in the provision of soil moisture as well as the VTCI imagery using the MODIS-Aqua data products. We assessed the 2010 flood effect on the four years (2011–2014) of drought conditions during winter wheat crop seasons. The obtained VTCI imagery and precipitation data were utilized to validate the drought and flood conditions in the year 2010 and the drought conditions in the years 2011–2014 during the winter-wheat-crop season. It is worth mentioning that over the four years (2011–2014) of the Julian day~D-041 year, the VTCI shows a stronger link with the accumulative precipitation anomaly (r = 0.77). It was found that for D-201 during the 2010 flood was the relationship was nonlinear, and in D-217, there was a negative relationship which revealed the flood timing, duration, and intensity. For D-281, a correlation (r = 0.97) was noted during fall 2010, which showed the drought and flood extreme conditions for the winter-wheat-crop season in the year 2010–2014. In regard to 2010, the Global Flood Monitoring System (GFMS) model employs the TRMM and TMPA data products to display the study region during the 2010 flood events and validate the VTCI results. This study’s spatial and temporal observations based on the observed results of the MODIS, TRMM, and TMPA satellites are in good agreement with dry and wet conditions as well as the flood runoff stream flow and flood intensity. It demonstrates the flood events with high intensity compared with the normality of flood with the complete establishment of flood events and weather extremes during the year of 2011–2014, thereby highlighting the natural hazards impacts. Our findings show that the winter wheat harvest was affected by the 2010 monsoon’s summer high rain and floods in the plain of Punjab (Pakistan).

A deep learning framework combining CNN and GRU for improving wheat yield estimates using time series remotely sensed multi-variables

Accurate and timely crop yield estimation is crucial for crop market planning and food security. Combining remotely sensed big data with deep learning for yield estimation has attracted extensive attention. However, it is still challenging to understand and quantify the time cumulative effects of crop growth over time for crop yield estimation. In this study, we combined the powerful feature extraction capability of the convolutional neural network (CNN) and the advantage of time series memory of the gated recurrent unit (GRU) network to develop a novel deep learning model called CNN-GRU for estimating county-level winter wheat yields in the Guanzhong Plain using three remotely sensed variables, vegetation temperature condition index (VTCI), leaf area index (LAI) and fraction of photosynthetically active radiation (FPAR). The CNN-GRU model was able to extract features related to yield from the input variables and the accuracy of the proposed model (R2 = 0.64, RMSE = 462.56 kg/ha, MRE = 8.90 %) was higher than that of the GRU model (R2 = 0.62, RMSE = 479.79 kg/ha, MRE = 9.34 %), and the CNN-GRU model’s reliability and robustness were confirmed by applying the leave-one-year-out cross-validation. Furthermore, we applied the proposed CNN-GRU model to simulate the wheat yields in the Plain pixel by pixel and examined the spatiotemporal patterns of the estimated yields. The distribution of yields presented the spatial characteristics of low yields in the east and high yields in the west, and the inter-annual variation characteristics of overall stability and steady increase. Additionally, we explored the possibility of timely prediction of winter wheat yield and the contribution of the multi-variables at different growth stages to yield estimation based on the ability of deep learning to reveal cumulative effects and non-linear relationships between influencing factors and yield. It was found that the information reflected by the multi-variables from late March to late April was important for yield estimation and the best prediction could be achieved approximately 20 days before the harvest of winter wheat. Our study demonstrated that combining CNN and GRU was an efficient and promising approach to improve yield estimation, offering great promise for global crop yield estimation.

Integrated weed management strategies for the depletion of multiple herbicide-resistant waterhemp (Amaranthus tuberculatus) seed in the soil seedbank

AbstractThe development of an integrated weed management (IWM) strategy for control of multiple herbicide-resistant (MHR) waterhemp can provide field crop producers with a strategy to deplete the number of waterhemp seeds in the soil seedbank. Field experiments were established on two commercial farms in Ontario, Canada, with MHR waterhemp in 2017. The number of waterhemp seeds in the seedbank at the Cottam and Walpole Island sites prior to establishing the experiments was 413 and 40 million seeds ha−1, respectively. The goal of this 9-yr study is to document the depletion in the number of waterhemp seeds in the seedbank after Years 3, 6, and 9 (spring 2020, 2023, and 2026) and to identify management practices that can reduce the number of waterhemp seeds by 95% or more. Relative to the number of seeds in the soil seedbank when the experiment was initiated, at the Cottam site after 3 yr of this experiment, in the “control” treatment (continuous soybean seeded in rows spaced 75 apart, and sprayed with glyphosate) there was a numeric 31% increase in the number of waterhemp seeds in the seedbank; in contrast, in the three-crop rotation of corn/soybean/winter wheat (with or without a cover crop after winter wheat harvest), soybean seeded in rows spaced 37.5 cm apart, with herbicide applications using a total of eight different herbicide modes of action resulted in a 65% to 66% decrease in the number of waterhemp seeds in the soil seedbank. At the Walpole Island site after 3 yr of this experiment, the number of waterhemp seeds in the seedbank was not affected by the IWM programs evaluated. Results indicate that a diversified integrated waterhemp management program dramatically decreased the number of waterhemp seeds in the seedbank at one of two sites.

Effects of Tillage on Soil Nutrients and Yield of Winter Wheat in Dry Loess Tableland

An experiment was carried out to find out whether long-term no-tillage poses a threat to soil fertility and crop yield at the Changwu Loess Plateau Agricultural Ecological Experiment Station of Northwest A&F University in Changwu County, Shaanxi Province. Before seeding winter wheat in September 2020, the three tillage methods, namely no-tillage, conventional and rotational tillage were conducted on the experimental field that had undergone three consecutive years of no-tillage. After the winter wheat harvest in 2021, total soil nutrients, available soil nutrients, and wheat yield in the soil layer of 0-30 cm were analyzed under various tillage methods. Results showed a decreasing trend in the contents of total nitrogen and soil organic carbon (SOC) in the soil layer of 0-30 cm under three tillage methods. The SOC content and total nitrogen in the 0-10 cm layer were no tillage > rotation tillage > conventional tillage. The contents of P and K decreased with an increase in the layer of 0-30 cm soil depth under the three tillage methods. The available P and K contents were decreased by 16.07, 32.74, 15.54 and 27.08%, respectively in the soil layer of 10-20, 20-30 cm, compared to those in the layer of 0-10 cm (P < 0.05). Using various tillage methods, the content of available P under conventional tillage was significantly reduced by 11.31% in the 0-10 cm layer compared to that under no-tillage. Soil available k content under conventional tillage and rotation tillage decreased significantly by 6.16 and 4.97% compared to no tillage (P < 0.05), respectively. In the layer of 20-30 cm soil, available P content was significantly increased under conventional tillage by 18.12% compared to that under no-tillage, and available K contents were significantly increased under conventional tillage by 17.17 and 9.22% compared to that under no-tillage and rotation tillage, respectively (P < 0.05). The winter wheat yield was in the order of conventional tillage > rotational tillage > no-tillage, with a significant difference between conventional and no-tillage (P < 0.05). Therefore, it is necessary to carry out proper conventional tillage or rotary tillage on the dry loess tableland where no-tillage has been carried out for a longer time. Bangladesh J. Bot. 51(4): 931-936, 2022 (December) Special

Prediction of Winter Wheat Harvest Based on Back Propagation Neural Network Algorithm and Multiple Remote Sensing Indices

Predicting the harvest time of wheat in large areas is important for guiding the scheduling of wheat combine harvesters and reducing losses during harvest. In this study, Zhumadian, Zhengzhou and Anyang, the main winter-wheat-producing areas in Henan province, were selected as the observation points, and the main producing areas were from south to north. Based on Landsat 8 satellite remote sensing images, the changes in NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index), and NDWI (Normalized Difference Water Index) were analyzed at different growth stages of winter wheat in 2020. Multiple regression analysis and Back Propagation (BP) neural network machine learning methods were used to establish prediction models for the harvest time of winter wheat at different growth stages. The results showed that the prediction model based on a BP neural network had high accuracy. The RMSE, MAE and MAPE of the training set and the test set were 0.531 and 0.5947, 0.3001 and 0.3104, 0.0114% and 0.0119%, respectively. The prediction model of winter wheat harvest date based on BP neural network was verified in the main winter wheat producing areas of Henan province in 2020 and 2021. The average errors were 1.67 days and 2.13 days, which were less than 3 days, meeting the needs for winter wheat production and harvest. The grain water content of winter wheat at harvest time calculated by the prediction model reached the grain water standard of the wheat combine harvester. Therefore, the prediction of the winter wheat harvest time can be realized based on multiple remote sensing indicators.