Winter Wheat Crops Research Articles

Quantifying the rainfall variability effects on crop growth and production in the intensified annual forage - winter wheat rotation systems in a semiarid region of China

Replacing summer fallow period (July to September, SF) with annual short-season forages in the traditional fallow-winter wheat (Triticum aestivum L.) system may maintain grain yield and improve productivity in the semi-arid environments. But the uneven and variability rainfall led to instable productivity of the annual forage–winter wheat cropping system. The aims of this study were to 1) quantifying rainfall variability effects on annual forage–winter wheat system crop growing process and productivity; 2) determine the optimal annual forage–winter wheat production system that will response better to future climate change. A four-year (2016–2020) field experiment was conducted to investigate the impact of replacing summer fallow period with annual forages including oat (FO, Avena sativa L.), soybean (SB, Glycine max L.), and vetch (FV, Vicia sativa L.) on plant height (H), leaf area index (LAI), and above-ground biomass (AByield) growth index dynamics under three different levels of rainfall manipulation i.e. 30 % of ambient rainfall exclusion (R-30 %), natural rainfall (CK), and 30 % of ambient rainfall increase (R+30 %). Additionally, we assessed the correlations between forage and winter wheat production with growing season precipitation across 12 rainfall scenarios. Average forage biomass values of oat, soybean, and vetch were 5.50, 4.29, and 2.82 t ha−1, respectively during summer fallow period. The average winter wheat grain yield values in SF, FO, SB, and FV were 3.78, 3.12, 4.02, and 3.18 t ha−1, respectively. Integrating oat into fallow period had negative effects on wheat growth and production, and the H, LAI, and AByield for FO were 63.7 %, 50.9 %, and 29.9 % lower than SF in dry year, but the wheat grain yield in SB were 18.2 % and 24.8 % greater than SF in normal and wet years. Across the four growing seasons, the forage and wheat yields were shown to be strongly related to precipitation, and increasing precipitation significantly enhanced the production. In 2016–2017 growing season, LAI of wheat in SF, FO, SB, and FV with R+30 % scenario was increased by 30.2 %, 21.7 %, 32.7 %, and 19.8 % and that with R-30 % scenario decreased by 23.2 %, 17.8 %, 24.7 %, 16.5 % compared CK, respectively. The traditional summer fallow practice had advantage for maintaining stability in wheat gain production, especially under dry years. In consideration of forage and wheat production to rainfall variability, integrating soybean into fallow season may be an efficient option to maintain wheat yield and produce high forage amount under future climate change on the Loess Plateau and similar semi-arid regions.

Crop Water Stress Index and Yield Relationships for Winter Wheat (Triticum aestivum) Crops Grown Under Different Drip and Flood Irrigated Treatments

ABSTRACTThe Crop Water Stress Index (CWSI) is a widely used method for quantifying crop water status and predicting yield. However, its evaluation across different irrigation methods and its stage‐specific response to crop yield is rarely evaluated. In this study, controlled field experiments were conducted on winter wheat using drip irrigation (DI) and flood irrigation (FI) during the 2021–2022 and 2022–2023 seasons in western Uttar Pradesh, India. The irrigation treatments included 50% MAD (maximum allowable depletion) (DI), 55% MAD (DI), 60% MAD (DI), 50% MAD (FI), local farmer's field replication (FI), rain‐fed, and well‐watered treatment (DI). The derived mean CWSI values for the irrigation treatments ranged from 0.03 to 0.66 in season 1 and 0.06 to 0.57 in season 2 across treatments. The seasonal mean CWSI for 50% MAD (DI) was 0.12 (season 1) and 0.11 (season 2), while 50% MAD (FI) yielded higher mean CWSI values of 0.29 (season 1) and 0.22 (season 2). The 50% MAD (DI) treatment produced the highest grain yield and water use efficiency in both seasons. A comprehensive analysis of stage‐specific CWSI values and grain yields revealed that grain yield was more sensitive to post‐heading CWSI as compared to pre‐heading CWSI values. Among the growth stages, CWSI values during the flowering stage were the most critical for predicting wheat yield. The study recommends that the CWSI values in the flowering and post‐heading stages are more relevant in predicting wheat yield accurately as compared to the pre‐heading and seasonal mean CWSI.

Towards a national model of humus (carbon) budget management in soils of agroecosystems in the Russian Federation

The prospect of adapting two methods for monitoring the fertility of agricultural soils (humus balance, HB) under spring and winter wheat crops (hereinafter referred to as grain crops) developed in the Russian Federation (RF) for the purposes of climate projects has been studied. It was revealed that the RosNIIzemproekt method (1998) underestimates the HB average value to -7.7 c/ha for RF. The RosNIIzemproekt method (1998) has logical errors in the calculation model and is not recommended for use. The TsINAO method (2000) has a more logical calculation model. According to this method, the average value of HB in soils for RF is generally positive and amounts to 3.3 c/ha (0.71 tCO2-eq/ha carbon units). This value constitutes ≈0.3% of average humus reserves in arable soils of the RF (108 tС/ha). The annual value of change in humus content under spring and winter wheat is incommensurably less than the total humus reserves in the soil. Statistically reliable assessment of changes in humus content requires a huge number of soil samples. This makes the verification procedure economically inexpedient. Another option is proposed to increase the time of humus accumulation. It is considered (IPCC, 2003) that a 20-year accumulation period is sufficient, which corresponds to the duration of soil climate projects. A coefficient (0.216) has been proposed for converting humus reserves (c/ha) to the value of a carbon unit (tCO2-eq/ha). The total sequestration of carbon by soils under grain crops in 2022 was about 11 million 914 thousand tCO2-eq. HB accounting significantly compensates for calculated emissions from agricultural production and reduces them by almost 10% (from 116 to 105 million tons CO2-eq in 2022). For both models of fertility monitoring, an assessment was made of the quality of the regression dependence of HB on the total biomass of photosynthesis (TBP) in soils under grain crops. It is shown that according to Fisher's t-test at a 5% significance level, the studied relationship is significant and characterized by the squares of the correlation coefficient (R2) equal to 0.554 and 0.998. In accordance with the Chaddock scale, the closeness of the correlative relationship between HB and TPB for winter wheat is assessed as high, and for spring wheat as very high.

Effects of Deficit-Regulated Irrigation on Root-Growth Dynamics and Water-Use Efficiency of Winter Wheat in a Semi-Arid Area

Water management is critical for wheat production under extreme drought conditions, and the mechanisms by which root dynamics and soil water utilization affect wheat yield are uncertain. This study was conducted in 2023–2024 under a mesophilic semi-arid climate with a two-factor partitioned experimental design, aiming to assess the response of different irrigation amounts in winter wheat crops on root growth and development, soil water utilization, and yields in different soil horizons. The results showed that variety and irrigation volume had significant effects on the spatial and temporal distribution of root and yield components, with irrigation volume having the greatest effect on yield. Compared with CK, deficit-regulated irrigation significantly promoted root penetration to deeper layers and delayed root senescence. DRWD, RLD, RSA, and RV decreased gradually with increasing soil depth, and the peaks of RLD, RSA, and RV appeared at the tassel to flowering stage, respectively; and under deficit-regulated irrigation, the contribution of the A2W4 treatment to stable yield was greater. Therefore, A2W4 is an effective water-saving irrigation method to improve grain yield and water-use efficiency under deficit-regulated irrigation.

Analytical derivation of optimal irrigation water depth for efficient irrigation scheduling.

Optimal irrigation water depth is a crucial parameter in irrigation engineering, often referred to as root zone depth. It is typically assumed to lie between 1 and 1.5m below the ground surface, depending on the crop and soil types as well as the practitioner's skill and experience. This approach can lead to inefficient irrigation scheduling. Coupling Richards' equation with the Soil Conservation Service Curve Number (SCS-CN) concept and using the three-phase diagram of soil column widely used in geotechnical engineering, this paper suggests an analytical expression for optimal irrigation water depth providing the maximum storage capacity of a soil depending on its hydraulic/storage properties. The results for winter wheat crop in different hydrologic soil groups show that the use of the proposed concept can lead to savings of 71.79% and 57.69% of irrigation water in sandy soils (HSG-A) compared to that used in traditional irrigation considering lump-sum 1.5m and 1m optimal irrigation water depths, respectively. In the case of silty loam soils (HSG-C), these savings can assume 52.42% and 28.62%, respectively. The proposed relation can also be of great help in volumetric assessment of field capacity, moisture content, maximum water storage capacity (of different agricultural soils), and avoiding the issue of waterlogging that may arise from over-irrigation and thus is useful in efficient irrigation scheduling as well as in sustainable agricultural water management.

Precision estimation of winter wheat crop height and above-ground biomass using unmanned aerial vehicle imagery and oblique photoghraphy point cloud data.

Crop height and above-ground biomass (AGB) serve as crucial indicators for monitoring crop growth and estimating grain yield. Timely and accurate acquisition of wheat crop height and AGB data is paramount for guiding agricultural production. However, traditional data acquisition methods suffer from drawbacks such as time-consuming, laborious and destructive sampling. The current approach to estimating AGB using unmanned aerial vehicles (UAVs) remote sensing relies solely on spectral data, resulting in low accuracy in estimation. This method fails to address the ill-posed inverse problem of mapping from two-dimensional to three-dimensional and issues related to spectral saturation. To overcome these challenges, RGB and multispectral sensors mounted on UAVs were employed to acquire spectral image data. The five-directional oblique photography technique was utilized to construct the three-dimensional point cloud for extracting crop height. This study comparatively analyzed the potential of the mean method and the Accumulated Incremental Height (AIH) method in crop height extraction. Utilizing Vegetation Indices (VIs), AIH and their feature combinations, models including Random Forest Regression (RFR), eXtreme Gradient Boosting (XGBoost), Gradient Boosting Regression Trees (GBRT), Support Vector Regression (SVR) and Ridge Regression (RR) were constructed to estimate winter wheat AGB. The research results indicated that the AIH method performed well in crop height extraction, with minimal differences between 95% AIH and measured crop height values were observed across various growth stages of wheat, yielding R2 ranging from 0.768 to 0.784. Compared to individual features, the combination of multiple features significantly improved the model's estimate accuracy. The incorporation of AIH features helps alleviate the effects of spectral saturation. Coupling VIs with AIH features, the model's R2 increases from 0.694-0.885 with only VIs features to 0.728-0.925. In comparing the performance of five machine learning algorithms, it was discovered that models constructed based on decision trees were superior to other machine learning algorithms. Among them, the RFR algorithm performed optimally, with R2 ranging from 0.9 to 0.93. In conclusion, leveraging multi-source remote sensing data from UAVs with machine learning algorithms overcomes the limitations of traditional crop monitoring methods, offering a technological reference for precision agriculture management and decision-making.

Effect of Crop Rotation on Biological Characteristics and Economic Indicators of Winter Wheat in Different Agroecological Conditions

The article deals with observations on plants and agrotechnical measures in accordance with the recommendations on the cultivation of plants in short rotation alternating and continuous crops consisting of cereal and inter-row cultivated plants under irrigation conditions. It is known that realizing the potential productivity of wheat in favorable soil and climate conditions is possible by applying high-level agrotechnics in various agro-ecological conditions. The highest indicators of spike elements of the Gobustan variety of wheat, which is the main source of research, were obtained in the crop rotation variant. In Absheron YTT, the spike length is 9.1 cm, the number of spikes is 17.4, the number of seeds is 43, and the mass of the seed is 1.62 g. The mass of 1000 grains are 41.8 g. 9.9 cm according to the mentioned indicators in Tarter BTS; 19.9 units; 50 units; It was determined to be 1.83 g: 40.9 g, which is 0.6-0.9 cm in regions, respectively, compared to continuous cultivation; 2.3-2.8 pieces; 4-3 units; An increase of 0.11-0.16 g and 3.1-3.4 g was obtained. The number of beans per plant in Absheron AEF is 45.6, the number of seeds is 106.3, the mass of seeds is 12.5 g, and the mass of 1000 seeds is 118.4 g. In Tarter RES, one plant has 52.5 beans, 128 grains, the mass of a grain is 13.9 g, and the mass of 1000 g of grain is 110.3 g. These indicators 4.0-4.3 units according to regions compared to continuous cultivation; 9.0-12.3 units; 1.2-1.3 g and 7.4-3.2 g indicate an increase. Thus, the crop rotation in 2 different agroecological conditions after the soybean predecessor had a significant effect on the spike and economic indicators of the winter wheat crop. The highest indicators of spike elements of the winter wheat Gobustan variety were obtained in the crop rotation variant. According to the results of the research, the highest grain yield in the regions was obtained in the mentioned option. Thus, in this variant, the grain yield of winter wheat per hectare was 40.4 cwt in Absheron AEF and 48.4 cwt in Tartar RES.

Use of Indices Applied to Remote Sensing for Establishing Winter–Spring Cropping Areas in the Republic of Kazakhstan

Farmers in Kazakhstan face unreliable water resources. This includes water scarcity in the summer, high fluctuations in precipitation levels, and an increase in extreme weather events such as snow, rain, floods, and droughts. Wheat production is regulated and subsidized by the Kazakh government to strengthen food security. The proper monitoring of crop production is vital to government agencies, as well as insurance and banking structures. These organizations offer subsidies through different levels support. Some farmers already use farmland soil monitoring combined with adaptive combinations of different crops. These include winter–spring plowing crop programs. Winter wheat crops are generally more adaptive and may survive summer droughts. Kazakhstan is a large country with large plots of farmland, which are complicated to monitor. Therefore, it would be reasonable to adapt more efficient technologies and methodologies, such as remote sensing. This research work presents a method for identifying winter wheat crops in the foothills of South Kazakhstan by employing multi-temporal Sentinel-2 data. Here, the researchers adapted and applied a Plowed Land Index, derived from the Brightness Index. The methodology encompasses satellite data processing, the computation of Plowed Land Index values for the swift recognition of plowed fields and the demarcation of winter wheat crop sowing regions, along with a comparative analysis of the acquired data with ground surveys.

Mapping winter wheat crop traits dynamic change and growth performance for variable rate application using Sentinel-1 and Sentinel-2

Site specific crop management for variable rate application is extensively recognized as a method for distributing agricultural input unevenly across a field, tailored to the diverse requirement of different areas. From the previous study, this approach proven to reduce agricultural input expenses by 10 % without impacting yield and ensure environmental sustainability. This study presents a new approach to delineate management zones for precision agriculture using crop biophysical property variability assessment within winter wheat fields. A multivariate random forest framework was developed to estimate winter wheat’s biophysical properties within fields from surface reflectance and backscatters of Sentinel-1 and Sentinel-2. Combining Sentinel-1 and Sentinel-2 data resulted in more precise estimation of the green area index (R²=0.98), aboveground dry biomass (R²=0.90), plant height (R²=0.94), and leaf nitrogen content (R²=0.78). Sentinel-2 alone was particularly effective in estimating shoot density (R²=0.94). These estimates were then used to create management zones for precision agriculture, classified based on agronomic performance benchmarks. The fuzzy c-mean clustering algorithm helped generate homogeneous management zones, considering the biophysical variations within fields.The ultimate goal is to integrate these biophysical property maps and management zones into crop management workflows. This integration will assist farmers in recognizing field variability and understanding its causes. Moreover, the spatial distribution of these zones supports variable rate application, guiding farmers towards more efficient, profitable, and sustainable crop management practices.

A multi-sensor drought index for improved agricultural drought monitoring and risk assessment in the heterogeneous landscapes of the China–Pakistan Economic Corridor (CPEC)

Droughts cause significant economic damage worldwide. Evaluating their impacts on crop yield and water resources can help mitigate these losses. Using single variables such as precipitation, temperature, the soil moisture condition index (SMCI) and the vegetation condition index (VCI) to estimate drought impacts does not provide sufficient information on these complex conditions. Therefore, this study uses station-based and remote-sensing-based data to develop new composite drought indexes (CDIs), including the principal component analysis drought index (PSDI) and the gradient boosting method drought index (GBMDI). The first dataset includes historical observations of the standardized precipitation index (SPI), standardized precipitation evapotranspiration index (SPEI), and the self-calibrated Palmer drought severity index (SC-PDSI) at the 1-, 3-, 6-, and 12-month timescales. The second dataset consists of remote-sensing-based data including the VCI, SMCI, temperature condition index (TCI), and precipitation condition index (PCI). We validated the results of PSDI and GBMDI by comparing them with historical drought events, in-situ drought indices, and annual winter wheat crop yield data from 2003 to 2022 using a regression model. Our temporal analysis revealed extreme to severe drought events during1990s and 2010s. GBMDI typically aligned with actual drought events and exhibited stronger correlations with in-situ drought indices than PSDI. We observed that drought intensity in winter were more severe than in summer. GBMDI was the most effective method, followed by PSDI, for assessing drought impacts on winter wheat yields. Thus, the proposed integrated monitoring framework and indexes offered a valuable and innovative approach to addressing the complexities of agricultural drought, particularly in evaluating its effects.

Seasonal dynamics of cereal aphid population

Goal. To compare the seasonal dynamics of cereal aphid abundance in the Steppe and Forest-Steppe zones during 2023 and to determine the factors that influenced it. Methods. To assess the state of the cereal aphid population on cereal crops, we used the results of personally conducted entomological phytosanitary monitoring of crops (according to generally accepted methods) in the farms of the Steppe and Forest-Steppe zones; information from current reports from the places where field experiments were conducted directly by the forecasting laboratory, as well as other laboratories of the IPP of NAAS, which is also confirmed by the materials of decadal reports of regional plant protection stations and signalization and forecasting points of the State Inspection of Plant Protection, confirmed by information on the phytosanitary status of regional state research stations. Cereal aphid adults and larvae were counted in populations of populations (in the crop phase, the end of the tube emergence is earing). Results. The state of cereal aphid populations on crops of cereal spiked crops in 2023 was studied, both in general in Ukraine and separately in the Steppe and Forest-Steppe zones. The dynamics of their number in farms of different natural and climatic zones was investigated, and an analysis of its peculiarities in the conditions of the year was carried out. Conclusions. In 2023, the harmfulness of cereal aphids on cereal crops remained at the level of long-term averages. The expansion of their harmful zone and an increase in their number was noted during the earing period (milk ripeness). On winter cereal crops, phytophages prevailed in the Steppe zone. In the Forest-Steppe zone, the phytophage was more damaging to winter cereals than to spring cereals. The results of entomological monitoring in Mykolaiv region (State Enterprise «Experimental Farming «Zori nad Bugom») showed that during the accounting period the bulk of aphids were concentrated on winter wheat crops, and winter barley was damaged in small numbers. On the contrary, the surveys conducted in Kyiv region (State Enterprise «Experimental Farming «Salyvonkivske») showed that in the second half of June — the first decade of July, the number of aphids on spring barley crops was approximately twice as high as on spring wheat. As a result of the study, it was practically confirmed that the optimal temperature regime for the development of cereal aphids is 16—20°C, and the relative humidity is 60—80%.

BIOTECHNOLOGICAL PRACTICES FOR GROWING CORN FOR GRAIN UNDER DIFFERENT PREDECESSORS IN THE CONDITIONS OF THE UKRAINIAN STEPPE

An important factor that determines the grain yield and productivity of corn is the previous crop. In the conditions of insufficient moisture in the Steppe region of Ukraine, the significance of the predecessor is determined by the accumulated moisture reserves. It is believed that the best predecessors for corn in the Steppe conditions are winter wheat and leguminous crops, while satisfactory ones are corn and barley, with sunflower considered a poorer predecessor. Corn can be grown in both repeated plantings and monoculture, but the agronomic practices affecting crop productivity in such crop rotations have not been studied sufficiently. A stationary study was established in 2005 at the Institute of Agriculture of the Steppe NAAS, with soil and climatic conditions corresponding to the Northern Steppe zone of Ukraine. A simple modified mid-ripening hybrid DK Veles was sown in the study. Seed inoculation was carried out with the biopreparation Mycofriend. The research results indicate that the predecessor was a significant factor influencing the formation of grain yield and productivity indicators of corn. When growing corn after soybeans, the average grain yield was 5.31 t/ha, after sunflower and corn predecessors it was 3.03 t/ha and 3.25 t/ha respectively, with no significant difference in yield between sunflower and corn predecessors. There was no significant increase in corn grain yield due to the action of the biopreparation factor, with a yield increase ranging from 0.01–0.06 t/ha, but a more active effect of the biopreparation was noted with the sunflower predecessor. Higher productivity indicators for grain units yield, feed units yield, and digestible protein units were achieved when growing corn after soybeans – 6.43 t/ha, 9.65 t/ha, and 0.573 t/ha respectively. There was no significant difference in productivity indicators between the sunflower predecessor and repeated corn cultivation. The highest indicators for grain units yield, feed units yield, and digestible protein units were obtained under the condition of seed inoculation with the biopreparation after the soybean predecessor – 6.44 t/ha, 9.68 t/ha, and 0.575 t/ha respectively.

Study of the Spectral Characteristics of Crops of Winter Wheat Varieties Infected with Pathogens of Leaf Diseases.

Studying the influence of the host plant genotype on the spectral reflectance of crops infected by a pathogen is one of the key directions in the development of precision methods for monitoring the phytosanitary state of wheat agrocenoses. The purpose of this research was to study the influence of varietal factors and disease development on the spectral characteristics of winter wheat varieties of different susceptibility to diseases during the growing seasons of 2021, 2022 and 2023. The studied winter wheat crops were represented by three varieties differing in susceptibility to phytopathogens: Grom, Svarog and Bezostaya 100. Over three years of research, a clear and pronounced influence of the varietal factor on the spectral characteristics of winter wheat crops was observed, which in most cases manifested itself as an immunological reaction of specific varieties to the influence of pathogen development. The nature of the influence of the pathogenic background and the spectral characteristics of winter wheat crops were determined by the complex interaction of the development of individual diseases under the conditions of a particular year of research. A uniform and clear division of the spectral characteristics of winter wheat according to the intensity of the disease was recorded only at a level of pathogen development of more than 5%. Moreover, this gradation was most clearly manifested in the spectral channels of the near-infrared range and at a wavelength of 720 nm.

The effect of green manure on the agrochemical properties of soil in winter wheat crops, yield and grain quality

The effect of green manure on the agrochemical properties of soil in winter wheat crops, yield and grain quality

THE INFLUENCE OF MULTICOMPONENT WINTER WHEAT SEED PROTECTANTS ON ITS PRODUCTIVITY AND QUALITY

We studied combined suspension compositions prepared by liquid-phase mechanical treatment based on the fungicides difenoconazole, tebuconazole, imazalil, fludioxanil, thiabendazole, prochloraz, sedoxan and the insecticides thiamethoxam, imidacloprid, plant growth regulators Enershanse, which showed a wide range of biological activity in field conditions. It was established that the main indicators of the quality of the final product - the nature of the grain, the amount of protein and gluten, glassiness, and the quality of gluten - depended on the fungicidal and insecticidal effects on the phytosanitary condition of winter wheat crops. All studied drugs had a protective effect. They contributed to the disinfection of winter wheat seeds from seed and soil pathology and harmful insects of the early period of plant development. It was found that for effective treatment of winter wheat seeds, it is best to use insectofungicidal preparations containing several components of different chemical classes. It was found that pre-sowing treatment of winter wheat seeds with a suspension composition of thiamethoxam + sedaxan + fludioxonil + tebuconazole in the form of Vibranse Integral, suspension concentrate provided the greatest increase in grain yield by 0.49 t/ha (7.3%) with a control yield of 6.74 t/ha. The use of this drug ensures a particularly high protein content in the grain (16.07%) and gluten (36.8%) of the first quality group. We have established diverse positive effects of the drug Vibranse Integral, manifested in enhancing the growth processes of the root system due to the presence of the sedaxane molecule, the purpose of which is aimed at the formation of a healthy and well-developed root system, increasing the stress resistance of plants to abiotic factors, and the manifestation of a good protective effect in relation to soil and seed infections. We determined the lowest, relative to other studied drugs, yield (6.17 t/ha) from the use of a suspension composition of thiamethoxam (262.5 g/l) + difenoconazole (25 g/l) + fludioxonil (25 g/l (Celest Top), but the grain was of high quality. All other seed protectants occupied an intermediate position between the above-mentioned drugs.

Influence of Fertilizer Systems and Tillage Methods on the Formation of the Assimilation Apparatus and Photosynthesis Productivity of Winter Wheat and Sugar Beet in the Central Chernozem Region

The effect of fertilizers and soil tillage on the photosynthesis productivity of winter wheat and sugar beet crops was studied in a stationary field experiment on leached chernozem of the Central Chernozem region. It was found that a significant increase in crop yield is achieved by optimizing soil tillage and fertilization, as well as by increasing the total area of the leaf surface, the photosynthetic productivity of which decreased per unit of leaf surface.

Phytopathogenic background regulation of winter wheat crops under organic cultivation

Phytopathogenic background regulation of winter wheat crops under organic cultivation

Population dynamics of wheat and predatory thrips in winter wheat agrocenosis in the forest-steppe of the Samara region

The current paper has presented the three-year study results (2021–2023) on recording the population dynamics of wheat and predatory thrips during the spring-summer vegetation period of winter common wheat in the forest-steppe of the Samara region. The purpose of the study was to determine the dynamics of the seasonal development of wheat and predatory thrips according to the phenophases of the development of winter common wheat in the forest-steppe of the Samara region. For this purpose, there were carried out the calculations using the mowing method with an entomological net on winter wheat crops in different phenophases of development, and the population of species and thrips were determined in the laboratory under a binocular. According to weather conditions, 2021 and 2023 were characterized as dry and hot, 2022 was characterized as cool with plenty of precipitation in the first half of the winter wheat vegetation period. The population dynamics of wheat and predatory thrips varied depending on the weather conditions of the spring-summer period of the year. In the hot years of 2021 and 2023 there were 2 periods of increase in population. In 2021, the period of maximum population of wheat thrips was observed from a heading stage to a flowering stage (1016 and 1048 specimen per 100 sweeps of the net) and in the phase of milky-wax ripeness (426 specimen per 100 sweeps of the net). In 2022, the population of wheat thrips on plants increased gradually, the peak was noted once during the flowering stage, amounting to 1084 specimen per 100 sweeps of the net. In 2023, a population increase was observed in the heading stage (1782 specimen per 100 sweeps of the net) and the phase of milky-wax ripeness (421 specimen per 100 sweeps of the net). In the hot years of 2021 and 2023 there were 2 periods of increase in predatory thrips’ population; the maximum number of entomophages was observed during the heading stage and amounted to 87 and 61 specimens per 100 sweeps of the net, respectively. In the cool year of 2022, there was one population increase during the flowering stage and amounted to 14 specimens per 100 sweeps of the net. In the phases of heading and flowering of plants, there were predominantly adult insects (imago), and in the phases of milky and milky-wax ripeness, there were predominantly found larvae of different ages. The weather conditions in 2021 and 2023 turned out to be more favorable for the development of wheat and predatory thrips than in 2022.

Effects of reduced pesticide use on winter wheat production in the Canadian Prairies

Winter wheat (Triticum aestivum L.) is a highly competitive crop with the potential to enhance on-farm revenue and reduce reliance on crop protection inputs. The adoption of winter wheat in the Canadian Prairies has varied significantly over recent decades; however, improved weed and disease management practices could facilitate stability of hectares cultivated. To assess current and alternative pesticide management practices, we conducted a study across 15 site-years at four locations over four years (2018-2022). Experimental treatments included pre-plant weed management (glyphosate vs. glyphosate mixed with pyroxasulfone+carfentrazone-ethyl), in-crop weed management (no in-crop herbicide vs. fall-applied 2,4-D vs. fall-applied 2,4-D+spring-applied site-year-specific herbicides) and in-crop fungicide management (no in-crop fungicide vs. one prothioconazole+tebuconazole application at ZGS60 vs. two prothioconazole+tebuconazole applications at ZGS32 and ZGS60). Pre-plant glyphosate alone and glyphosate tank-mixed with pyroxasulfone+carfentrazone-ethyl exhibited comparable effects on grain yield, quality parameters, and agronomic characteristics. In-crop weed management had no significant influence on these factors compared to the no in-crop herbicide control, suggesting that in-crop herbicide applications are unnecessary due to the high competitiveness of winter wheat against weeds. However, disease mitigation was prudent as single and double application of fungicide increased grain yield while maintaining grain protein concentration levels. A high-yielding, stable system for optimal grain yield typically required pre-plant weed management coupled with two fungicide applications. These observations confirm herbicide inputs can be reduced in a winter wheat cropping system but disease pressure requires careful cultivar selection with an emphasis on disease resistance as multiple applications of fungicides were needed to optimize grain yield.

Influence of cultivation methods on the soil aggregate state in the context of weed development in winter wheat plantations

Weed control in winter wheat crops is an important issue. There is a risk of increasing populations of certain weed species that are resistant to some of herbicides used for winter wheat crops. This could be controlled by a combination of agronomic, mechanical, chemical, and biological methods. After introducing winter wheat into the rotation and improving tillage, the weediness of regular black soils with perennial root and emerged weeds were significantly reduced. The formation of nodal and rudimentary roots had a significant effect on the productivity of winter wheat under different soil moisture conditions. The highest yield of winter wheat was obtained when sown at the optimum time, with higher stem density and ear productivity due to better grain fullness. We studied what effects did the tillage methods have on the aggregate state of the soil in relation to weed development in winter wheat crops, finding that the structural and aggregate composition of the soil played an important role in winter wheat crops, influencing both the development of the crop root system and the water-physical balance of the chernozem, as well as naturally influencing the course of erosion processes in the experimental plots, and having a universal dynamic in terms of adaptation of aggregation and disaggregation processes. Prolonged mechanical stress on soil can cause destruction of its structure. For instance, continuous ploughing or moldboardless tillage with little or no manure application may permanently reduce soil fertility by increasing humus mineralisation. Subsequently, these factors may cause a significant decline in the soil's structural and aggregate composition, resulting in larger amounts of dusty particles smaller than 0.25 mm and cloddy particles larger than 10–12 mm. The soil's structural condition before sowing winter wheat in early September, on average for 2011–2016, indicates increased dispersion of the tilth layer (0–10 cm) in the experimental variants where shallow disc tillage of 10–12 cm was applied. Increase in the number of clods larger than 10 mm in the areas where moldboardless tillage had been applied can be attributed to significant soil drainage. The soil's aggregate state was rated as good, with 8.7% in the 0–10 cm soil layer and 1.7% of clods > 10 mm in the 0–30 cm layer. In 2014–2016, it was rated as satisfactory, with 7.4% and 9.8% of clods > 10 mm, respectively. Shallow disc cultivation resulted in slightly worse indicators: 6.6% and 8.3% of clods > 10 mm in soil layer 0–10 cm and 0–30 cm, respectively, in 2011–2013; and 7.2% and 6.9% of clods > 10 mm, respectively, in 2014–2016. In general, the parameters of optimal structural condition were positive. The tillage method used had a considerable effect on weed growth and development, particularly for those with a root and rhizome structure. It also affected the prevalence and development of pests and diseases in winter wheat. Agrotechnical methods of weed control do not guarantee complete destruction of weeds. Mechanical moldboardless tillage to the depth of 14–16 cm and disc tillage to the depth of 10–12 cm left the fields with 4.1 to 8.8 annual weeds per square meter and 1.3 to 3.3 specimens of harmful root weeds such as Convolvulus arvensis, Lactuca tatarica and Cirsium arvense. Mechanical moldboardless tillage to the depth of 14–16 cm and disc tillage to the depth of 10–12 cm left the fields with 4.1 to 8.8 annual weeds per square meter and 1.3 to 3.3 specimens of harmful root weeds such as Convolvulus arvensis, Lactuca tatarica and Cirsium arvense. Post-harvest residues (4–5 t/ha) can provide almost complete protection against weeds by covering the soil surface. However, pests and diseases may spread more easily due to preservation of fungal spores on the surface of plant residues and preservation of pest larvae in the straw and soil. The distribution of weed seeds in the soil was altered when the rotational tillage of common chernozems in winter wheat cultivation technology had been replaced with energy–saving minimum tillage (shallow flat-cutting disc tillage). This resulted in the concentration of most of the weed seeds (85–90%) in the upper soil layer (0–10 cm).