As essential approaches for conservation agricultural practices, straw residue retention and crop rotation have been widely used in the Mollisols of Northeast China. Soil organic carbon, root development and microbial community are important indicators representing soil, crop and microbiota, respectively, and these factors work together to influence soil fertility and crop productivity. Studying their changes and interactions under different conservation practices is crucial to provide a theoretical basis for developing rational agricultural practices. The experiment in this study was conducted using the conventional practice (continuous maize without straw retention, C) and three conservation practices, namely, continuous maize with straw mulching (CS), maize–peanut rotation (R), and maize–peanut rotation with straw mulching (RS). Straw mulching (CS) significantly increased soil total organic carbon (TOC), active organic carbon (AOC), and microbial biomass carbon (MBC), but did not promote maize yield. Maize–peanut rotation (R and RS) significantly increased dissolved organic carbon (DOC) in the rhizosphere by promoting root growth, and maize yield (increased by 10.2%). For the microbial community structure, PERMANOVA and PCoA indicated that the bacterial community differed significantly between rhizosphere soil and bulk soil, but the fungal community shifted more under different agricultural practices. The correlation analysis indicated that the rotation system promoted the association between the soil DOC and the microbial community (especially the bacterial community), and straw mulching enhanced the connection between the soil TOC and the fungal community. Some plant growth–promoting rhizobacteria (includingBacillus,Streptomyces,Rhizobium, andPseudomonas) were enriched in the rhizosphere soil and were increased in the rotation system (R and RS), which might be due to an increase in the soil rhizosphere DOC level. These beneficial microbes had significantly negative correlations with several fungal groups (such asMycosphaerella,Penicillium,ParaphomaandTorula) that were classified as plant pathotrophs by FUNGuild. These results indicated that ensuring plant root development and improving root–bacteria interactions are of great importance to guarantee crop yield when implementing conservation tillage practices.

High yields and low carbon emissions are new challenges for modern crop production. Balancing the crop yield and reducing greenhouse gas (GHG) emissions has become a new field of agronomic technology innovation. Cereal–legume intercropping is a typical diversification planting system, which has been expected to achieve the dual goals of high production and low GHG emissions. However, the synergistic effect of integrating various technologies in an intercropping system on GHG emissions and whether it will achieve the high yield and low emissions goal remains to be determined. Therefore, bibliometric analysis has investigated the worldwide development trend of cereal–legume intercropping designs. The literature on the GHG emissions of the cereal–legume intercropping system was summarized. Additionally, the effects and mechanisms of different agricultural management methods regarding soil nitrous oxide and carbon dioxide emissions in the cereal–legume intercropping system were summarized. The research on GHG emissions of cereal–legume intercropping systems in non-growing seasons must be revised. In situ observations of GHG emissions from intercropping systems in different regions should be strengthened. This work is valuable in supporting and evaluating the potential of GHG reduction in a cereal–legume intercropping system in various farming areas.

Rotational cover cropping is a key practice in conservation agriculture. To investigate the effects of maize-crop rotation with cover crops combined with nitrogen management on maize yield, nitrogen use efficiency (NUE), and related traits, a field experiment was conducted from 2023 to 2025. The experiment employed a split-plot design. The main plots consisted of three cropping systems: continuous maize (Fumin 985’) monoculture (CK), maize rotated with rapeseed (CC-Ra), and maize rotated with rye (CC-Ry). The subplots comprised five nitrogen (N) fertilizer application rates (0, 75, 150, 225, and 300 kg ha⁻¹) respectively. Compared to CK, CC-Ra and CC-Ry increased average maize grain yield by 5.93% and 12.89%, and NUE by 8.09% and 2.89%, respectively. At the silking stage, these treatments increased average DM by 6.45% and 16.55%, respectively, and by 5.75% and 15.01% at the maturity stage. The maximum LAI was enhanced by an average of 16.24% and 26.82%, while the net photosynthetic rate (Pn) of the ear leaf increased by 12.29% and 26.32%, respectively. In contrast, the leaf net assimilation rate (NAR) decreased by an average of 19.98% and 18.01%. While higher N application boosted yield, it sharply reduced NUE. Notably, yields under rotations at 225 kg N ha⁻¹ matched the yield of continuous maize at 300 kg N ha⁻¹. This suggests that the inclusion of cover crops can substitute for a portion of nitrogen fertilizer input while maintaining stable maize yield. Principal component analysis fundamentally clarified that maize rotational cover cropping combined with nitrogen fertilizer management significantly promotes yield. While cover crops increase maize yield, they also facilitate nitrogen accumulation and enhance NUE, albeit at the expense of leaf net assimilation rate. Therefore, balancing the source–sink characteristics of the maize population is necessary to avoid the loss of advantages conferred by rotational cover cropping. This study holds significant implications for incorporating cover crops into maize production systems.

Waterlogging stress severely limits crop photosynthesis and energy supplies, resulting in significant yield reductions. However, the critical duration of waterlogging stress during the maize jointing stage remains unclear, and the physiological and molecular mechanisms underlying its effects on photosynthetic efficiency and energy synthesis in maize require further investigation. In this study, we systematically analyzed the responses of physiological traits, transcriptomic profiles, and the yield formation in maize (Zea mays L.) to varying waterlogging durations imposed during the jointing stage, including 0 days (CK), 2 days (F2), 4 days (F4), 6 days (F6), 8 days (F8), and 10 days (F10). Our results indicate that the (1) grain weight (GW) showed no significant difference between F2 and CK. However, the GW in F4, F6, F8, and F10 decreased significantly by 17.49%, 26.45%, 60.24%, and 100.00%, respectively, compared to the CK. (2) Compared with the CK, the malondialdehyde content progressively increased from F4 to F10, while antioxidant enzyme activity gradually decreased. The chlorophyll content declined by 29.93% to 57.38%, and net photosynthetic efficiency decreased by 13.82% to 38.93%. Although the leaf sucrose content in from F4 to F10 gradually decreased, the leaf starch content remained stable in F4 and F6. In contrast, the starch content in F8 and F10 leaves was significantly reduced by 37.55% and 47.60%, respectively, compared with CK. (3) A transcriptomic analysis revealed that during from F2 to F4, genes encoding photosystem I subunit protein, such as PSAD, and the cytochrome b6f complex proteingene PETC were downregulated. At F6, these key genes encoding photosynthetic proteins were upregulated. However, at F8 and F10, their expression was significantly downregulated. Concurrently, genes related to ATP synthesis (e.g., ATPD) as well as starch and sucrose metabolism (e.g., SPP2, SS1) were also downregulated. In summary, when waterlogging stress persists for no longer than 6 days, plants can maintain their starch content to supply energy for growth, thereby ensuring basic developmental needs. When waterlogging persists for more than 6 days, energy synthesis is impaired, and the nutrient transport to the grains is significantly inhibited, ultimately resulting in a substantial reduction in yield. Therefore, 6 days of waterlogging can be considered the critical threshold for significant yield loss in maize during the jointing stage.