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Irrigation is a common practice in agriculture to increase crop yield. However, the impacts of irrigation on microbial-mediated processes that influence soil carbon (C) pools and crop yield remains largely unknown. Therefore, we conducted a 2-year field experiment to investigate the effects of low (I1, 80% field capacity, 80%FC), medium (I2, 90%FC), and high (I3, 100%FC) irrigation upper limits on rhizosphere soil bacterial community, soil organic carbon (SOC) content, and wheat yield. The results showed that as the irrigation upper limit increased, the α-diversity of the bacterial community decreased. The bacterial community structure significantly differed across various irrigation upper limits. As the irrigation upper limit increased from low (80%FC) to medium (90%FC) or high (100%FC), the abundance of copiotrophic taxa (Proteobacteria, Actinobacteria, Bacteroidetes) decreased, and oligotrophic taxa (Acidobacteria) increased, enhancing the decomposition of persistent C pools. In the second year of the irrigation experiment, the I2 and I3 treatments significantly decreased microbial biomass carbon (MBC), SOC content (by 4.62–7.30%), and the microbial quotient (MQ) compared to I1. Wheat straw biomass and grain yield also decreased as the irrigation upper limit increased from 80%FC to 100%FC, with key bacterial taxa (Proteobacteria, Actinobacteria, and Chloroflexi) and functional processes (glycan biosynthesis and metabolism; folding, sorting, and degradation; translation; transport, and catabolism) playing key roles in wheat grain formation. Our findings indicate that adjusting irrigation levels affects the rhizosphere soil bacterial communities, and that the lowest upper limit of irrigation application (80%FC) is associated with maximum crop yield and microbial diversity. • As the irrigation upper limit increased, the α-diversity of the bacterial community decreased. • Increasing the irrigation upper limit (80–100%FC) shifted the bacteria from copiotrophic taxa to more oligotrophic taxa. • Bacterial community composition and metabolic function affected wheat yield. • Irrigation could alter the abundance of microbial metabolic functions associated with soil C. [ABSTRACT FROM AUTHOR]

Climate warming has increased the frequency of droughts and excessive precipitation, adversely affecting crop growth, particularly under traditional intensive tillage. No-till improves crop tolerance to extreme events by reducing soil evaporation and improving soil structural stability to enhance soil water storage capacity and crop resistance, but long-term mono-no-till cakes the soil, reducing crop yield. Combining intensive tillage with no-till can compensate for some deficiencies arising from conventional tillage or single no-till. A three-year field experiment was conducted in wet (2020) and normal (2019 and 2021, where a drought event occurred in 2021) years to study the effect of tillage practices on summer maize productivity under different precipitation types. Treatments included conventional tillage (CT), no-tillage (NT), ridge cultivation with no-tillage (RNT), and conventional tillage of winter wheat combined with no-tillage of summer maize (NC). Compared with NT, NC and RNT significantly reduced soil bulk density and increased soil porosity in the 0–20 cm soil layer. Compared with CT, NC and RNT significantly improved aggregate stability, NC increased available soil water storage by 19.7% in the dry season (P < 0.05), and NC and RNT significantly reduced lodging rate in the rainy season. Over the three years, NC and RNT maintained higher maize yields (NC: 10.3 t ha–1 and RNT: 10.0 t ha–1) than CT (9.2 t ha–1), and NC had significantly higher yield stability than CT. Meanwhile, NC and RNT had higher precipitation use efficiency (PUE; NC: 21.2 kg ha–1 mm–1, RNT: 20.7 kg ha–1 mm–1) than NT (20.1 kg ha–1 mm–1) or CT (19.1 kg ha–1 mm–1). In terms of combined productivity, NC and RNT provide a more suitable soil environment for crop growth and maintain higher yield than NT and CT. NC rotation is recommended as the optimal tillage system for sustainable crop production under semi - arid agricultural conditions. RNT can be extended to areas prone to flooding with abundant rainfall. These results offer a benchmark for future studies on regional maize production under climate change. • The effect of tillage on maize productivity under abnormal precipitation conditions was analyzed. • Combined tillage effectively reduces the risk of crop failure due to seasonal drought or flooding. • The high yield is due to higher water use efficiency in the dry season and higher resistance to lodging in the wet season. • No-tillage and conventional tillage rotation tillage（NC） is suitable for maize production in most areas. • Ridge cultivation with no-tillage (RNT) is suitable for areas with abundant precipitation. [ABSTRACT FROM AUTHOR]

We characterize the variation in the inner lateral environment with five indexes. The emitter clogging risk was affected by the drip irrigation time. The emitter clogging risk was significantly correlated with sediment mass and particle size composition. Lateral flushing changes the adhesion direction of the clogging materials and lowers the emitter clogging risk. Emitter clogging is one of the most important limiting factors affecting the promotion of drip irrigation. To examine the impact of the irrigation time on the lateral environment and to develop an optimal way to mitigate the emitter clogging risk, 4 different irrigation times (3, 7, 10 and 30 times) were examined with each irrigation period lasting 2 daily hours. Then, the lateral inner environment was studied from the perspectives of the mass, particle size composition, mineral composition, microbial content of the sediment in the lateral (includes sediment deposited in and adhered to the lateral, DS and AS, respectively). The index of the emitter clogging risk was used to indicate the emitter clogging level of the drip irrigation system. The results indicated that emitter clogging risk (R ec) was significantly correlated with the DS mass, AS mass, rate of change of the AS mass and fractal dimension (p < 0.01), and the AS mass was correlated with the bacterial content in the AS (p < 0.05). This finding indicates that R ec was affected by the lateral inner environment. The DS affected the changes in R ec , mainly through influencing the mass of clogging substances in the grid structures and the particle size across the labyrinth channel. The increasing AS captures nutrients and provides a suitable environment for the growth of bacteria in the laterals, inlet grid and labyrinth channel. Additionally, the mass of clogging substances (mainly the AS) increased steadily during the process of particle adhesion, which leads to irreversible clogging. The R ec declined rapidly in the initial stage of irrigation and then gradually decreased over the irrigation duration. There was a boundary between short and long irrigation times (between irrigation times of approximately 7 and 10 in this research), which was the optimum lateral flushing period. [ABSTRACT FROM AUTHOR]