Xining Gao

To clarify the effectiveness of different stubble heights and mulching patterns for wind erosion control in maize–peanut intercropping systems, this study was conducted in the black soil region of Northeast China using a combination of wind tunnel simulation and field wind erosion monitoring. Monocropped peanut bare land was used as the control (CK). Four wind tunnel treatments were established: maize stubble with mulching (WT-1), maize stubble without mulching (WT-2), and peanut strip with maize straw mulching (WT-3). Additionally, seven field treatments were established, comprising mulched and non-mulched plots at three stubble height levels (low, medium, and high), as well as a mulched peanut plot without stubble (T7). Wind erosion intensity and amount were systematically measured across all treatments. The results showed that: (1) Wind erosion intensity increased exponentially with wind speed (R² = 0.90–0.96, p < 0.001). Over the full range of wind speeds, wind erosion intensity was consistently greater in CK and WT-2 than in WT-3 and WT-1. The three mulching treatments exhibited distinct protective characteristics across different wind speed intervals: rapid response of surface mulching at low wind speeds, enhanced wind erosion control of standing stubble at moderate wind speeds, and diminished stubble protection but sustained mulching advantage at high wind speeds. The WT-1 treatment maintained an anti-wind erosion efficiency of 70.15% even at the extreme wind speed of 18 m·s⁻¹. (2) Field wind erosion amounts ranked as CK > T6 > T2 > T4 > T1 > T7 > T5 > T3. The medium stubble with mulching treatment (T3) showed a net dust deposition effect with a wind erosion amount of −0.35 g, demonstrating the optimal erosion reduction performance. (3) Standing stubble and surface mulching synergistically increased aerodynamic roughness by 22.86–394.44%, effectively reducing near-surface wind speed by 30.32–55.55%. Meanwhile, straw mulching reduced soil water evaporation, increased pre-sowing surface soil water content by 5.4–126.01%, and enhanced inter-particle cohesion, thereby effectively suppressing soil wind erosion. Therefore, after harvest in the maize–peanut intercropping system in the black soil region of Northeast China, the combined application of maize straw mulching on peanut strips (T7) and medium stubble (40–50 cm) with mulching on maize strips (T3) is recommended as an optimal technical strategy for wind erosion control in the study area and similar brown soil-dominated wind erosion-sensitive regions after autumn harvest.

Drought stress is a common environmental stress factor for soybeans (Glycine max L.), significantly impeding the growth and yield. Therefore, studying the photosynthetic and physiological characteristics during two crucial growth and development periods, namely the flowering and grain-filling stages, under drought stress and rewatering conditions is of great significance for clarifying the physiological and photosynthetic regulatory response mechanisms of soybeans to drought stress. In this study, the cultivar ‘Liaodou 15’ was subjected to mild drought (L, 65% field capacity) and severe drought (H, 50% field capacity) treatments during the flowering and grain-filling stages for 7, 14, and 21 days respectively. At the conclusion of the stress period, rewatering (R) was carried out. Results showed that the stomatal limit value increased and intercellular CO₂ concentration decreased with the increase in drought stress intensity, and the decrease in net photosynthetic rate was dominated by stomatal factors at the flowering stage. At the grain-filling stage, the stomatal limit value decreased and intercellular CO₂ concentration increased with the increase in drought stress intensity, and the decrease in net photosynthetic rate changed from stomatal factors to non-stomatal factors. Drought stress led to peroxidation damage. In this study, it significantly increased the contents of soluble protein and malondialdehyde (MDA), as well as the activities of peroxidase (POD) and superoxide dismutase (SOD). On the other hand, rewatering had a compensatory effect on various physiological indices of soybean leaves. Under drought stress, the yield indices of soybeans were affected during both the flowering and grain-filling stages. Specifically, the yield during the flowering stage decreased by 15.63%–55.47%, and the yield during the grain-filling stage decreased by 24.17%–59.63%. This indicates that drought has a greater impact on the yield of soybeans during the grain-filling stage. Moreover, as the duration and intensity of drought increase, the reduction in yield becomes more significant, and the yield is the lowest when there is severe drought stress for 21 days. Our study elucidates the complex physiological and photosynthetic responses of soybeans to drought stress and rewatering, which provides valuable insights for improving soybean cultivation strategies under drought environments.

Drought, a prevalent environmental stressor, has had significant consequences on soybean (Glycine max L.), notably impeding its growth and production. Therefore, it is crucial to gain insight into the regulatory responses of soybean plants exposed to drought stress during soybean flowering in the field. In this study, the cultivar ‘Liaodou 15’ was performed light drought (LD, 24.3% soil moisture content), moderate drought (MD, 20.6% soil moisture content) and severe drought (SD, 16.9% soil moisture content) treatments at flowering stages of soybean and then rehydrated (30% soil moisture content) until harvest. The yield-related indicators were measured and revealed that MD and SD treatments significantly reduced 6.3% and 10.8% of the 100-grain weight. Soybean plants subjected to three drought stresses showed that net photosynthetic rates were 20.8%, 51.5% and 71.8% lower in LD, MD and SD than that of CK. The WUE increased by 31.8%, 31.5% and 18.8% under three drought stress treatments compared to CK. In addition, proline content was 25.94%, 41.01% and 65.43% greater than that of CK under three drought stress treatments. The trend of the MDA content was consistent with that of the proline content. SOD activity was significantly increasing by 10.86%, 46.73% and 14.54% under three drought stress treatments. The activity of CAT in the SD treatment increased by 49.28%. All the indices recovered after rehydration. Furthermore, 54,78 and 51 different expressed metabolomics (DEMs) were identified in the LDCK/LD, MDCK/MD and SDCK/SD groups, respectively. There were 1,211, 1,265 and 1,288 different expressed genes (DEGs) were upregulated and 1,003, 1,819 and 1,747 DEGs were downregulated. Finally, combined transcriptomic and metabolomic analysis suggested that 437 DEGs and 24 DEMs of LDCK/LD group, 741 DEGs and 35 DEMs of MDCK/MD group, 633 DEGs and 23 DEMs of SDCK/SD group, were highly positively correlated in soybean plants under drought stress. Drought stress induced the expression of the PAO1, PAO4, PAO5 and P5CS genes to promote the accumulation of spermidine and proline. Our study elucidates the responses of drought-stressed soybean plants in the field and provides a genetic basis for the breeding of drought-tolerant soybean plants.

Global climate change poses a great impact on crop growth, development and yield. Soybean production in Northeast China, which is one of the traditional dominant soybean production areas in China, is of great significance for developing the domestic soybean industry and reducing dependence on imported soybeans. Therefore, it is crucial to evaluate the impacts of future climate change on soybean yield in Northeast China, and to propose reasonable adaptation measures. In this study, we took Fujin city of Heilongjiang province in Northeast China as an example, and used the CROPGRO-soybean model in DSSAT (Decision Support System for Agrotechnology Transfer) to simulate the impacts of future climate change on soybean yield in the four periods of the 2020s (2021-2030), 2030s (2031-2040), 2040s (2041-2050) and 2050s (2051-2060) under two representative concentration pathway (RCP) scenarios (RCP4.5 and RCP8.5), and further determine the best agronomic management practices. The results showed that the calibrated and validated model is suitable for simulating soybean in the study area. By analyzing the meteorological data under future climate scenarios RCP4.5 and RCP8.5 from the PRECIS regional climate model, we found that the average temperature, cumulative precipitation and cumulative solar radiation would mostly increase during the growing season in Fujin city of Heilongjiang province. Combined with the model simulation results, it is shown that under the effect of CO₂ fertilization, future climate change will have a positive impact on soybean yield. Compared to the baseline (1986-2005), the soybean yield would increase by 0.6% (7.4%), 3.3% (5.1%), 6.0% (16.8%) and 12.3% (20.6%) in the 2020s, 2030s, 2040s and 2050s under RCP4.5 (RCP8.5).Moreover, the optimal sowing dates and the optimal supplemental irrigation amount under RCP4.5 (RCP8.5) are May 10 (May 5) and 50 mm (40mm), respectively. Under future climate conditions, the agronomic management practices, such as advancing the sowing date and supplementary irrigation in the key stage of soybean growth would increase soybean yield and make soybean growth more adaptable to future climate change.

Northeast China (NEC) is one of the main soybean-producing areas among the northern-latitude regions. Climate warming leads to frequent extreme disasters, and the threat of chilling damage to soybean production in NEC cannot be ignored. The study aimed to construct a dynamic disaster identification index based on the static evaluation of soybean after the disaster, taking into account the process of soybean chilling damage and using the historical disaster records to realize the dynamic prediction and analysis before the disaster. Taking soybean in NEC as the research object, chilling damage indicators of soybeans in NEC were constructed by dividing the mature regions, using daily temperature anomaly and negative temperature anomaly day data with the comprehensive consideration of the chilling damage intensity, duration, and temperature recovery. The results showed that the comprehensive indicators determined by the cumulative value of temperature anomaly—the cumulative days of negative temperature anomaly had better applicability in NEC than the single factor indicator. The indicator results were basically consistent with the historical disaster records, and the accuracy rate of the indicator verification reached 90.9%. Based on the analysis of the constructed indicators, the frequency of delayed chilling damage in NEC showed a fluctuating downward trend from 1961 to 2020. The station ratio of delayed chilling damage in NEC showed a fluctuating downward trend, with the most obvious downward trend occurring for severe damage, followed by moderate damage, and the least obvious trend observed for light damage. The scope of chilling damage gradually narrowed, with the frequency increasing from southeast to northwest. The high-risk areas of chilling damage were concentrated mainly in the northern part of Heilongjiang Province and the East Four Leagues. The risk of chilling damage in most areas of Jilin Province and Liaoning Province was relatively low. The study results provide basic support for the risk research of soybean chilling damage and for ensuring disaster monitoring and early warnings, and the risk assessment based on the chilling damage process has positive significance for adjusting agricultural structure and improving the distribution of soybean varieties.

Drought is the most common environmental stress and has had dramatic impacts on soybean (Glycine max L.) growth and yield worldwide. Therefore, to investigate the response mechanism underlying soybean resistance to drought stress, the drought-sensitive cultivar “Liaodou 15” was exposed to 7 (mild drought stress, LD), 17 (moderate drought stress, MD) and 27 (severe drought stress, SD) days of drought stress at the flowering stage followed by rehydration until harvest. A total of 2214, 3684 and 2985 differentially expressed genes (DEGs) in LD/CK1, MD/CK2, and SD/CK3, respectively, were identified by RNA-seq. Weighted gene co-expression network analysis (WGCNA) revealed the drought-response TFs such as WRKY (Glyma.15G021900, Glyma.15G006800), MYB (Glyma.15G190100, Glyma.15G237900), and bZIP (Glyma.15G114800), which may be regulated soybean drought resistance. Second, Glyma.08G176300 (NCED1), Glyma.03G222600 (SDR), Glyma.02G048400 (F3H), Glyma.14G221200 (CAD), Glyma.14G205200 (C4H), Glyma.19G105100 (CHS), Glyma.07G266200 (VTC) and Glyma.15G251500 (GST), which are involved in ABA and flavonoid biosynthesis and ascorbic acid and glutathione metabolism, were identified, suggesting that these metabolic pathways play key roles in the soybean response to drought. Finally, the soybean yield after rehydration was reduced by 50% under severe drought stress. Collectively, our study deepens the understanding of soybean drought resistance mechanisms and provides a theoretical basis for the soybean drought resistance molecular breeding and effectively adjusts water-saving irrigation for soybean under field production.