Climate change and variability are projected to alter the geographic suitability of lands for crops cultivation. Accurately predicting changes in the potential current and future land suitability distribution dynamics of wheat (Triticum aestivum), soybean (Glycine max) and rice (Oryza sativa) crops due to climate change scenarios is critical to adapting and mitigating the impacts of bioclimatic changes, and plays a significant role in securing food security in East Asia region. This study compiled large datasets of wheat, soybean and rice occurrence locations from GBIF and 19 bioclimatic variables obtained from the WorldClim database that affect crops growth. We recognized potential future suitable distribution regions for crops under the one socioeconomic pathway, (SSP585) for 2021–2040 and 2041–2060, using the MaxEnt model. The accuracy of the MaxEnt was highly significant with mean AUC values ranging from 0.833 to 0.882 for all models evaluated. The jackknife test revealed that for wheat, Bio4 and Bio12 contributed 17.6% and 12.6%, for soybean Bio10 and Bio12 contributed 15.6% and 49.5%, while for rice Bio12 and Bio14 contributed 12.9% and 36.0% to the MaxEnt model. In addition, cultivation aptitude for wheat, soybean, and rice increased in southeast China, North Korea, South Korea, and Japan, while decreasing in Mongolia and northwest China. Climate change is expected to increase the high land suitability for wheat, soybean, and rice in East Asia. Simulation results indicate an average decrease of unsuitable areas of -98.5%, -41.2% and -36.3% for wheat, soybean and rice from 2060 than that of current land suitability. In contrast, the high land suitable for wheat, soybean and rice cultivation is projected to increase by 75.1%, 68.5% and 81.9% from 2060 as compared with current. The findings of this study are of utmost importance in the East Asia region as they present an opportunity for policy makers to develop appropriate adaptation and mitigation strategies required to sustain crops distribution under future climates. Although the risks of wheat, soybean and rice cultivation may be significantly higher in the future because of high temperatures, heat waves, and droughts caused by climate change.

Legume/maize intercropping has been practiced in many countries as a sustainable cropping system, but the effects of intercropping legumes with maize together with N application rates on biomass yield, quality, water-use efficiency (WUE), and nitrogen use efficiency (NUE) are limited under arid conditions in Northwest China. Field experiments were carried out in arid areas of Northwest China from 2019 to 2020 with three planting patterns (LM: Dolichos lablab (Lablab purpureus L.)/silage maize (Zea mays L.) intercropping; FM: Fodder soybean (Glycine max L.)/silage maize intercropping; M: silage maize monoculture) and four N application levels (N1: 0 kg N ha⁻¹; N2: 120 kg N ha⁻¹; N3: 240 N kg ha⁻¹; N4: 360 N kg ha⁻¹). The results showed that nitrogen fertilizer had a significant (p < 0.01) effect on total yield, WUE, and various nutrient parameters and the interaction between planting mode and nitrogen fertilizer had no significant effect on the above indicators, but had a significant (p < 0.01) effect on NUE. Compared with N1, the N3 and N4 treatments significantly increased fresh and hay yield, crude protein yield, crude protein concentration, and crude fat concentration of maize, legumes, and the whole silage system, and decreased the concentration of neutral detergent fiber (NDF) and acid detergent fiber (ADF). In comparison with N1, the 2-year average total biomass yield of N3 and N4 increased by 60.38% and 56.45%, respectively, and the total crude protein yield increased by 106.71% and 100.00%, respectively. High N input treatments (N3 and N4) significantly increased WUE_B (the WUE of legume and maize biomass), N concentration, N uptake, and NUE than N1, and the 2-year average NUE of N3 was 59.52% greater than that of N4. The results also show that LM and FM increased crude protein concentration and decreased NDF and ADF concentration compared with M, and the forage quality of LM was greater than that of FM. In contrast with M, LM and FM increased biomass yield by 3.70% and 1.72%, crude protein yield by 32.05% and 22.82%, and WUE_B by 10.49% and 6.02%, respectively. Application of 240 kg N ha⁻¹ in the Dolichos lablab–maize intercropping systems produced better dry biomass yield with increased forage qualities than other treatments, but the economic analysis is needed before making a recommendation.

In semi-arid areas of China, the ridge-furrow mulched with plastic film (RF) cultivation system is a common water-saving agricultural technique where the shortage of water resources has become a serious problem. Therefore, we aimed to explore whether this cultivation is actually an improvement over the traditional flat planting (TF) method while testing two deficit irrigation (150, 75 mm) levels to grow winter wheat. Furthermore, we examined the responses of the anti-oxidative defence system and photosynthetic capacity of winter wheat flag leaves under three simulated rainfall (275, 200 and 125 mm) conditions. The results showed that the RF system with 150 mm deficit irrigation and 200 mm simulated rainfall condition (RF2₁₅₀) treatment raised soil water content (%) at the jointing and flowering stages and achieved higher net photosynthesis rates (Pn) in flag leaves. Furthermore, such improvements were due to the reduction of malondialdehyde (MDA) content and oxidative damage during different growth stages of winter wheat. The RF2₁₅₀ treatment significantly increased the activities of superoxide dismutase (SOD); peroxidise (POD), catalase (CAT) and ascorbate peroxidase (APX) and the content of soluble protein (SP) during different growth stages of winter wheat. Furthermore, RF2₁₅₀ treatment attained the highest value at the flowering stage, while also exhibiting significant declines in contents of proline, MDA, H₂O₂ and O₂ in flag leaves. The higher free H₂O₂ and O₂ scavenging capacity and better anti-oxidative enzyme activities under the RF2₁₅₀ treatment were due to the lower level of lipid peroxidation, which effectively protected the photosynthetic machinery. The net photosynthetic rate of flag leaves was positively correlated with SOD, POD, CAT, APX and SP activities, and negatively correlated with proline, MDA, H₂O₂ and O₂ contents. We concluded that the RF2₁₅₀ treatment was the better water-saving management strategy because it significantly delayed flag leaf senescence and caused the increases in SWC, WUE, Pn, antioxidant enzyme activities and grain yield of winter wheat grown in semi-arid regions of China.