Soybean Crop Research Articles

Impact of Pendimethalin on Growth and Reproduction of Eisenia fetida

Earthworms play a crucial role in soil quality and agricultural practices, and their populations can be influenced by various factors, including the presence of pesticides like pendimethalin used in soybean crop. This study aims to evaluate the toxicity of pendimethalin on Eisenia fetida, a common naturalized exotic earthworm species found in Kota, India. Five sets of 10 worms were exposed to different concentrations of pendimethalin (ranging from 0.474 to 47.4 mg/kg dry weight), with one set of control soil. After four weeks, the growth rate and reproduction of Eisenia fetida were significantly reduced by pendimethalin exposure, highlighting the potential negative impact of this herbicide on soil ecosystems.

Comparative Analysis of Biochar Derived from Rice Straw and Soybean Straw

Aim: Recycling agricultural postharvest waste and re-introducing it again into farmland is one of the tangible ways to address zero waste dream, soil infertility and climate change. Pyrolysis of crop leftovers into biochar remains the most acceptable alternative for proper management of crop waste. The possibility of sustainable biochar production practices and multi-functionality features makes it promising to fufill an increasing demand for soil amendment, agricultural sustainability, environmental protection, cutting-edge materials and mitigation of climate change. Methodology: Same amount (14450 g) in feedstock of rice straw (RS) and soybean straw (SS) undergo slow pyrolysis separately to produce biochar. Physical (percentage yield, moisture, ash, volatile matter, bulk density, pH, electrical conductivity), chemical characterization (Microwave Plasma Atomic Emission Spectroscopy (MP-AES), Scanning Electron Microscope Energy Dispersive X-ray (SEM-EDX), Fourier Transformed Infrared (FTIR) and Thermogravimetric Analysis and Derivative Thermogravimetry (TGA and DTA)) and evaluation of bochar was determined. Results: Rice straw biochar (RSB) recorded a higher char yield of 42.1%. Both lignocellulosic biochars were black and porous with a higher silica (10.6%) content in RSB and higher carbon (82.2%) content in SSB as was revealed by SEM-EDX. Higher ash 27.1%, volatile matter (VM) 31.3% and moisture 29.4% content was seen in RSB compared to SSB because of feedstock composition. Rice straw biochar show higher peaks of macro and micro mineral elements K(14561.21mg/kg), Ca (2401.28 mg/kg), and Na(1735.27 mg/kg) than soybean straw biochar. FTIR was used to identify functional groups that might act as cation adsorbents. As the temperature increased, the TGA and DTG graphs showed mass loss and sample breakdown. Conclusion: Rice and soybean crop wastes were converted into biochar, a nutrient-rich material that maybe utilized to balance acidic soils promoting healthy plant growth and also protecting the environment.

Functional Identification of miR2119 Targeting ADHs in Modulating Soybean Resistance to Heterodera glycines.

Soybean cyst nematode (SCN, Heterodera glycines) is a sedentary endoparasite nematode that results in severe economic losses in soybean crops. miRNAs play crucial roles in plant responses to nematode. However, the role of miR2119 responding to SCN stress in soybean. Here, we demonstrated that the transcript levels of polycistronic precursors containing miR2119 and miR398a were significantly reduced in soybean upon nematode infection. Promoter of the miR2119-398a precursor analysis was conducted containing a GUS reporter gene. GUS activity assays demonstrated a decrease in miR2119-398a promoter during SCN infection. Overexpression of polycistronic precursor miR2119-398a (OE-premiR2119-398a) and miR2119 precursor (OE-premiR2119) rendered soybean more susceptible to SCN. Conversely, silencing miR2119 (STTM2119) increased soybean resistance against SCN. Furthermore, RNA-seq analysis revealed that miR2119 is involved in many defense signaling pathways. GUS reporter gene assays demonstrated that miR2119 targets GmADH1.1a and GmADH1.1b. Functional analysis indicated that ADHs act as a major role in responding to H. glycines by modulating reactive oxygen species (ROS) levels. Together, the findings reveal a novel mechanism by which the polycistronic precursor miR2119-398a coordinately regulates in response to H. glycines. Additionally, miR2119 becomes an essential element contributing to H. glycines by modulating ADH activity and ROS homeostasis in soybean.

Impact of Long-term Application of Fertilizers and FYM on Nutrient Uptake by Soybean Crop and Properties of Black Soil

Long Term Fertilizer Experiment (LTFE) play an important role in understanding the complex interactions involving plant, soil, climate, management practices and their effect on soil productivity over a long period of time. The present investigation is a part of ongoing All India Coordinated Research Project on Long Term Fertilizer Experiment with Soybean-Wheat Cropping Sequence, which was initiated since 1972. The experiment was carried out in a randomized block design consisting of eight treatments, viz. 50% NPK, 100% NPK, 150% NPK, 100% NP, 100% N, FYM (100% NPK+FYM), 100% NPK (-S) and Control. The significant nutrient content with nutrient uptake by soybean was noted in 100% NPK+FYM treatment over the control plot. It was also observed that nutrient content with nutrient uptake increased significantly with consecutive doses of fertilizers. On the other hand, 100% N and in the control group had the lowest value. However, adding fertilizer P in addition to N (100% NP) increased nutrient content and nutrient uptake by soybean crop. The highest. Soil organic carbon content was recorded with 100% NPK dose+FYM followed by 150% NPK treatment combination which could apparently due to the synergistic contribution of integration of fertilizer and FYM application. Similarly, the available N,P, K and S content in soil were found highest with 100% NPK + FYM followed by 150% NPK fertilizer dose. However, the lowest content was noted in control where crop was grown without fertilizers. Available sulphur was significantly higher over control in all the treatments receiving single super phosphate.

Spectral indices with different spatial resolutions in recognizing soybean phenology.

The aim of the present research was to evaluate the efficiency of different vegetation indices (VI) obtained from satellites with varying spatial resolutions in discriminating the phenological stages of soybean crops. The experiment was carried out in a soybean cultivation area irrigated by central pivot, in Balsas, MA, Brazil, where weekly assessments of phenology and leaf area index were carried out. Throughout the crop cycle, spectral data from the study area were collected from sensors, onboard the Sentinel-2 and Amazônia-1 satellites. The images obtained were processed to obtain the VI based on NIR (NDVI, NDWI and SAVI) and RGB (VARI, IV GREEN and GLI), for the different phenological stages of the crop. The efficiency in identifying phenological stages by VI was determined through discriminant analysis and the Algorithm Neural Network-ANN, where the best classifications presented an Apparent Error Rate (APER) equal to zero. The APER for the discriminant analysis varied between 53.4% and 70.4% while, for the ANN, it was between 47.4% and 73.9%, making it not possible to identify which of the two analysis techniques is more appropriate. The study results demonstrated that the difference in sensors spatial resolution is not a determining factor in the correct identification of soybean phenological stages. Although no VI, obtained from the Amazônia-1 and Sentinel-2 sensor systems, was 100% effective in identifying all phenological stages, specific indices can be used to identify some key phenological stages of soybean crops, such as: flowering (R1 and R2); pod development (R4); grain development (R5.1); and plant physiological maturity (R8). Therefore, VI obtained from orbital sensors are effective in identifying soybean phenological stages quickly and cheaply.

Effect of Novel Biostimulants on Performance of Black Gram and Soybean in Peninsular India

ABSTRACT The objective of modern agriculture includes environmental sustainability, low production costs, and higher productivity. Biostimulants are composed of humic acids, hormones, algae extracts, plant growth-promoting bacteria, amino acids, and a chain of peptides. Black gram and soybean crops are of immense economic significance. The growth and yield of these crops are limited by supply of nutrients. The potentiation of the early growth of plants by treating seeds with these substances has been one of the adopted alternatives, which often promote physiological changes that stimulate growth. The field experiment was conducted with randomized complete block design and replicated four times. Effects of different biostimulants at different concentrations as foliar spray and seed treatment were examined on growth, yield parameters, and yield of black gram (TAU-1) and soybean (JS-335) during kharif 2020 and 2021. Results showed that foliar application of Quantis biostimulant @ 5 ml L−1 recorded higher growth, yield parameters, and seed yield (897 kg ha−1), biological yield (1209 kg ha−1), production efficiency (13.00 kg day−1 ha−1) in black gram and seed treatment with Epivio Energy @ 2 ml kg−1 fetched higher seed yield (1403 kg ha−1), biological yield (2914 kg ha−1), production efficiency (16.13 kg day−1 ha−1) along with higher growth and yield parameters in soybean. It can be concluded that they will help in achieving higher growth and yield of black gram and soybean.

Effect of Ni and Fe Co-Application on the Soybean Crop Grown in Nickel and Iron Deficient Soils of Mirzapur District

ABSTRACT Considering the importance of nickel and iron nutrition for the soybean crop, their deficiency inhibits the yield drastically specially in the area where soybean crop is dominant. To encounter this problem, a pot experiment was conducted in glass house on low nickel and iron soil in Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, during 2019–20 and 2021–22. The study was carried out to investigate the effect of Ni (nickel) and Fe (iron) on the post-harvest soil parameters, growth, yield, nutrient uptake and nutrient content of soybean crop. There were 10 treatments with two levels of Ni (5 and 10 mg kg −1) and Fe (10 and 20 mg kg−1) with recommended dosage of fertilizers nitrogen, phosphorus, potassium (8.93, 35.71, and 17.86 mg kg−1) applied to all treatments except control. The result of the experiment revealed that the co-application of nickel and iron@10 mg kg−1 and 20 mg kg−1 (RDF + Ni10Fe20), resulted in the increase in plant height, greeness index, no of seed per pod, no of pod per plant, seed yield, and stover yield. Similar, findings for the post- harvest soil parameter indicated that there was increase in pH, electrical conductivity, and organic carbon content of soil. DTPA (Diethylenetriaminepentaacetic acid) extractable Ni, Fe, Zn, and Cu, also found highest in treatment where nickel and iron@10 mg kg−1 and 20 mg kg−1 (RDF + Ni10Fe20) were applied in soil, but in case of DTPA extractable Mn, the highest amount was found in treatment where nickel and iron@10 mg kg−1 and 10 mg kg−1 (RDF + Ni10Fe10) was applied in soil. The soil microbial biomass carbon and urease activity was also found highest in the treatment where nickel and iron@10 and 20 mg kg−1 was applied in soil. The minimum plant height, greeness index, no of seed per pod, no of pod per plant, seed, and stover yield was recorded in treatment where only RDF(T1) was applied. Similar, result recorded for the post-harvest soil parameters. So, overall findings of the pot experiment revealed that the conjoint application of nickel and iron has resulted in better yield of soybean crop.

Effect of nozzles on disease control with spraying fungicides in soybean crops

ABSTRACT The productivity of the soybean crop (Glycine max) can be limited by several factors, including diseases. In the integrated management of diseases, one of the strategies used is chemical control. The aim of this experiment was to evaluate the influence of spray nozzle types on the chemical control of fungal diseases in soybean plants. The experimental design was randomised blocks, with six treatments and four replications. The treatments consisted of control (without fungicide application on soybean plants) and application of fungicides with different spray nozzles: hollow cone jet, double flat jet, extended range flat jet, wide angle flat jet and air induction flat jet. The sprayer used was the backpack pressurised by carbon dioxide CO2. The experiment was installed in the Campos Gerais region (Paraná, Brazil); during three cropping seasons. The evaluated variables were incidence and severity, spray quality (covered area, droplet density, and relative amplitude) and yield components. It was concluded that the chemical control of fungal diseases in soybean plants reduced the proliferation of pathogens and losses in crop yield. There were significant changes in spraying quality in all analysed variables. There were no differences among the spray nozzle types regarding the analysis of incidence, severity and soybean yield components.

Evaluating the impact of phyto-hormones on the morpho-biochemical traits of soybean through seed treatment and foliar application

Global climate variations, mainly extreme temperatures reduce crop production and contributed to global food insecurity. Plant growth regulators (PGRs) improve physiological efficiency, photosynthetic capacity, and assimilate partitioning in field crops. However, their influence on soybean (Glycine max L.) yield and seed quality is under-researched. This study investigates the synergistic effects of auxin (2,4-D) and gibberellin (GA3) at 60 and 90 mg L−1 concentrations. This study investigates the impact of phytohormones, specifically gibberellic acid (GA3) and 2,4-dichlorophenoxyacetic acid (2,4-D), on the morphological and biochemical traits of soybean (Glycine max L.) through seed treatment and foliar application. These Growth regulators were applied through seed treatment at the time of sowing and foliar application at the time of flowering initiation stage. The experiment was designed using a RCBD arrangement and each block replicated thrice time. Seed treatment with 2,4-D at 90 mg/L showed that maximum plant height (116.80 cm), first node height (8.04 cm), No. of branches per plant (18.67), root length (18.12 cm) stem diameter (0.05 cm), no. of pods per plant (32.60), seed yield (1532.30 kg ha−1), biological yield (4109.30 ha−1), and harvest index (39.36 %). The GA3 (seed treatment) at conc. of 90 and 60 mg L−1 resulted in a significantly increased no. of nodule fresh weight, nodules per plant, and dry weight respectively. But the no. of seeds per pod did not showed significant results throughout the study. However, the foliar applied of 2,4-D at 90 mg L−1 resulted in significantly increased leaf area index (LAI) compared to the seed treatment. PGRs had a significant influence on quality traits. Thus, the application notably improved the potential of soybean and successful oilseed crop. Therefore, it is showed that using PGRs are extremely helpful for attaining higher growth, yield production, and improved quality of soybean.

SCREENING OF NEW SOYBEAN CULTIVARS AND CULTIVAR SAMPLES TOWARDS COMMON DISEASES IN KAZAKHSTAN

As part of the strategy to diversify cultivated areas and increase the profitability of agricultural enterprises, oilseeds, including soybeans, represent a promising direction for the development of the agricultural sector in the country. Kazakhstan is among the top 20 soybeanproducing countries globally. However, significant damage to soybean crops in the region was affected primarily by fungal diseases, leading to 20-50 % yield losses. This article presents field experiments conducted in the arid submontane agro-climatic Zhambyl region, focusing on the resistance of the global soybean collection. The study used 276 soybean varieties from Eastern Europe, Western Europe, North America, East Asia, and Kazakhstan. Screening of world soybean collection from 25 countries for field resistance towards various pathogens demonstrated a total of 197 soybean sources resistant to Cercospora sojina, 260 resistant to Septoria glycines, 76 resistant to Pseudomonas solanacearum, and 174 resistant to Peronospora manchurica. Among the tested samples, 24 soybean varieties of different origins exhibited high resistance to all pathogens, accounting for only 8.79% of those evaluated in the field during this experiment. These findings highlight the importance of identifying and utilizing disease-resistant soybean varieties to mitigate the impact of fungal diseases and improve soybean production in the region.

Inoculative releases of Telenomus podisi Ashmead (Hymenoptera: Scelionidae) for management of the stink bug complex in soybean crops

Inoculative releases of Telenomus podisi Ashmead (Hymenoptera: Scelionidae) for management of the stink bug complex in soybean crops

Directional aspects of crop yield correlation: Implications for insurance rating and contract design

AbstractWe estimate directional anisotropic models of linear correlation for crop yields. We find that directional distances (i.e., the degree to which yield correlation decays depending on direction) tend to differ from one another, with east to west distances being “longer” than north to south distances (i.e., correlation tends to decline slower in the east to west direction), at least for the major crops of corn and soybeans. Results for wheat are somewhat ambiguous. However, in all cases, average yield aggregates made up of east to west linked counties tend to be more accurate than is the case for north to south linkages. Implications for rating and contract design in the US area yield federal crop insurance program are offered.

Forecasting Cost Risks of Corn and Soybean Crops through Monte Carlo Simulation

Considering that investing in the production of corn and soybeans is conditioned by production costs and several risks, the objective of this research work was to develop a simulation model for the prediction of the production costs of these commodities, considering the variability and correlation of key variables. The descriptive analysis of the data focused on measures such as mean, standard deviation, and coefficient of variation. To evaluate the relationship between commodity and input prices, Spearman’s demonstration coefficient and the coefficient of determination (R2) were used. A Monte Carlo simulation (MCS) was used to evaluate the variation in production costs and net revenues. The Predictor tool was used to make predictions based on historical data and time series models. This study was made for the period between 2018 and 2022 based on data provided by fifty companies from the state of São Paulo, Brazil. The results showed that the production cost/ha of corn faces a high-cost risk, particularly when production and market conditions are characterized by high levels of volatility, uncertainty, complexity, and ambiguity. The model proposed forecasts prices more accurately, as it considers the variation in the costs of inputs that most significantly influence the costs of corn and soybean crops.

Biological response of Anticarsia gemmatalis (Lepidoptera: Noctuidae) to Bacillus thuringiensis berliner var. kurstaki at sublethal concentrations

The soybean caterpillar, Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae), damages this plant. This pest is controlled, mainly, with chemical products which makes it necessary to to develop management strategies for its management in the soybean crop. Feeding and development of A. gemmatalis larvae fed on soybean leaves treated with Bacillus thuringiensis Berliner var. kurstaki at different concentrations (0,5, 1, 2, 4, 6, 8 μg.mL-1 ) for 24 h were studied in the laboratory. The LC50 and LC90 after 24 h from hatching and at the last instar, development period, adult emergence, weight gain by larva, pupa weight, and dry food weight ingested besides of A. gemmatalis were evaluated. The LC90 value decrease with the development of this insect. Mortality in the third instar of this pest was proportional to the B. thuringiensis concentrations. Emergence of A. gemmatalis adults was higher with 0,5 μg.mL-1 concentration of this bacterium and in the control.

Herbal Companion Crops as an Example of Implementation of Sustainable Plant Protection Practices in Soybean Cultivation

This study aimed to assess the effect of using selected herbs as companion crops in soybean cultivation on the yield and overall health of soybeans. A three-year field experiment (2021–2023) was conducted using a randomized block design with three replications, where the primary experimental variable was the sowing method. The innovative cropping system involved cultivating soybeans alongside different companion herbs, such as alyssum (Lobularia maritima L.), fennel (Foeniculum vulgare Mill.), borage (Borago officinalis L.), French marigold (Tagetes patula L.), calendula (Calendula officinalis L.), and a herbal mixture referred to as ‘MIX’. The study showed that cultivation of soybean with fennel improved the quantitative and qualitative characteristics of the yield, with a significant increase in seed yield (on average by 0.27 t ha−1) as well as protein (7.67%) and oil yield (8.57%) compared to the pure soybean crop. The following fungal diseases were identified during the three-year study period (2021–2023): Cercospora leaf blight, Ascochyta blight, Fusarium wilt, and downy mildew. Cultivation of soybean with herbs as companion crops was implemented to improve the health of soybean to a varied extent. Borage, marigold, and calendula companion crops reduced infection of soybean by the fungi C. kikuchii and F. oxysporum. Cultivation with fennel and marigold was also beneficial for soybean health. On the other hand, cultivation with sweet alyssum and a mixture of herbs increased the occurrence of the fungus A. sojaecola. Cultivation of soybean in association with herbs is legitimate and requires further research given the priorities facing 21st-century agriculture.

Agronomic Evaluation Study: Use of Caiapônia Shale as Magnesium Supplementation for Soybean (Glycine max) and Maize (Zea mays) Cultivation

The soil of the cerrado is acidic, with high levels of iron and aluminum, and has low fertility due to weathering, which removes elements such as magnesium. To increase the availability of magnesium, essential for various plant processes, an alternative is the use of agrominerals rich in this element. The objective of this work was the agronomic evaluation of the use of Caiapônia shale as magnesium supplementation for soybean and corn crops. It is characterized as Magnesium Silicate containing 18% Magnesium Oxide (MgO) in its composition, in addition to the minerals Montmorillonite, Albite and Ilite. The product was screened to 0.425 mm in sieve no. 40. The study was conducted at the School of Agronomy of the Federal University of Goiás, located in the municipality of Goiânia, Goiás, in a greenhouse in two soils: Red Latosol (LV) and Yellow Latosol (LA). The treatments of Caiapônia Shale (CS) were increasing doses (0, 50, 100, 200 and 400 kg. ha-1 of MgO), in addition to the reference agrominerals, Dianutri (SiMg) and Ibar (MgO) and Wollastonite, source of Ca, with addition of MgO. The experimental design was completely randomized, with eight treatments conducted in quadruplicate. The variables analyzed were magnesium and calcium content and pH in the soil. The Caiapônia Shale (CS) released Mg+2, increasing the availability of magnesium, especially in LV in the first year of soybean and residual in corn in the second year, while in LA it was efficient in the first year.

Unique findings of <i>Phoma</i>-like fungi associated with soybean

Ascochyta leaf blight of soybean is a widespread disease caused by several closely related Phoma-like species, this disease often leads to significant crop losses. Among Phoma-like species from Didymellaceae family, the most frequently associated with symptomatic soybean tissues are species of the genera Boeremia and Didymella. Currently reliable species identification in Didymellaceae relies on polyphasic approach based on consolidated species concept and combined molecular phylogenetic, micromorphological and cultural features. At least three loci are commonly used for reconstruction of the molecular phylogeny of Didymellaceae: internal transcribed spacer (ITS) of the ribosomal DNA, partial RNA-polymerase II gene (rpb2), and β-tubulin (tub2). As a result of long-term phytosanitary monitoring of soybean crops, soybean leaves with symptoms of Ascochyta blight were collected from major soybean producing areas of Russia. From surface sterilized plant tissues more than 100 isolates of Phoma-like fungi were obtained and stored in the collection of pure cultures of the Laboratory of Mycology and Phytopathology (MF, All-Russian Institute of Plant Protection). Most of them, as a result of multilocus phylogenetic analysis, were identified as Boeremia and Didymella species. Eight isolates were identified as species of other genera, suspected to be rare findings. The aim of this study was to identify these eight isolates based on multilocus phylogenetic analysis, as well micromorphological, cultural, and pathogenicity data. Multilocus phylogenetic analysis has resulted in identification of all eight isolates to species level. Single isolate from the Ryazan region was Neoascochyta graminicola. Three other from three different districts of the Amur region were Remotididymella capsici. Two isolates from the Primorskiy territory and Amur region were Stagonosporopsis heliopsidis. Another two from two districts of the Amur region were S. stuijvenbergii. Pathogenicity tests have resulted in conclusion, that all studied isolates were not pathogenic for soybean leaves. Probably, these Phoma-like species are associate with soybean as saprophytes or endophytes. For all these Phoma-like species Glycine max was detected as substrate for the first time. Neoascochyta graminicola is widespread in Europe in association with Poaceae plants. There are only two findings of Remotididymella capsici in the world, both from leaves of Capsicum annuum. First finding was made in the former USSR in 1977 and was identified based on only morphological features. Second findings was collected in the Fiji and verified with multilocus phylogenetic analysis. Stagonosporopsis heliopsidis isolates were revealed in the USA, Canada, Netherlands and Russia and this fungus was believed to be specific for Asteraceae plants. Isolates of Stagonosporopsis stuijvenbergii are known only from soil in the Netherlands. Thus, such species as Neoascochyta graminicola and Stagonosporopsis stuijvenbergii were revealed in the Russia for the first time. Studied Remotididymella capsici isolates were first confirmed findings of this fungus in Russia. Additionally to detailed phylogenetic data, the manuscript is supplement with a detailed description of the cultural and micromorphological features of all species.

Water use efficiency and canopy temperature response of soybean subjected to deficit irrigation

Deficit irrigation is a key strategy for improving water use efficiency (WUE) under irrigated conditions. However, there is a lack of information regarding the optimal water replacement that have minimal negative effects on soybean productivity. The objective of this study was to determine the water replacement levels associated with insignificant grain yield (GY) losses in soybean crops. A rain shelter experiment was conducted using a randomized complete block design with six replicates. Eight irrigation replacement levels, L120, L100, L90, L80, L70, L60, L50, and L40, were applied, where L100 was the reference treatment that kept soil moisture content along the soil profile under field capacity conditions and all other replacement levels were a fraction of this reference level. Grain yield ranged from 2.2 Mg ha-1 in L40 to 4.4 Mg ha-1 in L100, with a significant GY reduction in irrigation levels below 70%. The average crop water stress index (CWSI) ranged between 0.26 at L120 and 0.66 at L40 irrigation levels. WUE varied significantly only for the extreme irrigation levels studied, with the greatest value at the L40 irrigation level (1.2 kg m-3) and the lowest value at the L120 irrigation level (0.65 kg m-3), whereas for the intermediate irrigation levels from 50 to 100%, the WUE was equal to approximately 1.1 kg m-3. The relationship between CWSI and GY (R2 = 0.85) suggested that the maximum GY occurred at a CWSI of 0.34. In addition, the relationship between CWSI and WUE (R2 = 0.73) showed that as evapotranspiration decreased, crop temperature increased. In conclusion, the implementation of a continuous water deficit in soybeans is feasible for farmers in water-scarce areas, but the minimum value of area productivity must be considered, even though WUE increases under more intensive values of water deficit.

Measurements and predictions of seedling emergence forces

Quantifying seedling emergence pressure or forces (soil impedance to seedling) during the process of plant emergence is difficult in a practical setting. In this study, a mechanical seedling testing device was designed and calibrated to measure seedling emergence pressures experienced by conical or spherical mechanical seedling in soil with varying compaction levels. The data were analysed to generate regression models for predicting seedling emergence forces. Results showed a high correlation between the seedling emergence pressure and soil resistance. The resultant regression model produced a coefficient of determination (R2) of 0.99. After incorporating the morphological characteristics of soybean cotyledon and maize coleoptile into the model, the predicted seedling emergence forces increased with the soil compaction level. During the emergence process, average emergence force of the soybean seedlings was 11.8 N for the lowest compaction level and 28.5 N for the highest compaction level, and the corresponding values of the maize seedlings were 0.2 N and 0.6 N. In a non-compacted field plot, maize crop had a 95.4% emergence rate and soybean crop had 97.2%, whereas for a compacted plot, the corresponding emergence rates were decreased to 19.1% and 60.5%. Inferences made from the study provide information on the dynamics of soil-seedling interaction, which have important implications for managing soil compaction in crop production.

Spatiotemporal Dynamics and Evolution of Grain Cropping Patterns in Northeast China: Insights from Remote Sensing and Spatial Overlay Analysis

Understanding the spatiotemporal patterns and driving mechanisms of cropping patterns’ evolution tailored to local conditions is crucial for the effective allocation of black soil in northeast China and the advancement of agricultural development. This study utilized the Google Earth Engine platform to extract the spatial distribution data of major grain crops in northeast China for the year 2022. Using crop classification data from 2000 to 2022, the spatial overlay analysis method identified cropping pattern types based on spatial and temporal changes. The primary cropping patterns identified were continuous maize cropping, maize–soybean rotation, mixed cropping, and continuous soybean cropping. Simultaneously, this research constructed three distinct crop periods: Period I (2000–2002), Period II (2010–2012), and Period III (2020–2022). Over three periods, these patterns covered 94.73%, 88.76%, and 86.39% of the area, respectively. The evolution of the dominant cropping pattern from Period I to Period II involved the transition from continuous soybean cropping to continuous maize cropping, while from Period II to Period III, the main shift was from continuous maize cropping to maize–soybean mixed cropping. From a spatial perspective, since Period I, maize has increasingly replaced soybean as the dominant crop, with continuous maize cropping expanding northward and continuous soybean cropping contracting. The maize–soybean rotation area also migrated northward, particularly in the core area of the Songnen Plain, evolving mostly into continuous maize cropping. Maize cropping areas exhibited significant regional characteristics, being densely distributed in the Sanjiang Plain and Liaohe Plain, and along major tributaries in northeast China. Consequently, the interplay of the natural environment, economic policies, and agricultural technologies drove these changes. The findings offer valuable insights for optimizing cropping patterns and developing rotation systems in northeast China.