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The evaluation of soil particle composition and salt dynamics is essential for promoting the sustainable development of oasis agriculture in arid regions under long-term mulched drip irrigation (MDI). In this study, we employed the space-for-time substitution method to investigate the long-term effects of MDI on soil particle composition and salinity. Additionally, seven fields, with MDI durations ranging from 0 to 16 years, were selected to represent the primary successional sequence though time in Northwest China. Soil samples were collected from three soil depths (0–30 cm, 30–60 cm, and 60–100 cm) and then analyzed in the laboratory for soil particle composition and salt content. Our findings demonstrated that influenced by the depth of mechanical cultivation and the maximum wetting front depth, the long-term application of MDI significantly altered both the structure of soil layers and the composition of soil particles after 8 years. Soil sand content and soil salinity gradually decreased, whereas the content of soil silt and clay increased with increasing MDI duration throughout 0–100 cm soil depth. Furthermore, the rates of soil desalination stabilized after 10 years of MDI application, with desalination levels exceeding 90% in the 0–100 cm soil layer. Additionally, the soil mass fractal dimension (Dm) exhibited an upward trend across 0–100 cm soil depth. The changes in soil particle composition indirectly influenced the variations in Dm and salt content. Our study demonstrated that long-term application of MDI effectively mitigated soil salinity, changed soil structure, and ultimately enhanced soil quality and cotton yield. [ABSTRACT FROM AUTHOR]

Biodegradable films are considered an environmentally-friendly alternative to traditional polyethylene (PE) film mulches, as they effectively reduce film pollution in the farmland when using mulched drip irrigation. However, the effects of different degradable films on soil micro-climate and maize growth have not been examined, especially under different irrigation amounts, which are critical considerations for oasis agriculture in arid areas. Therefore, we conducted a field study in 2019–2020 on maize farmland using two biodegradable films, one with an 80-day induction period (M 80) and the other with a 100-day induction period (M 100), and compared them with traditional PE film (M PE). Four irrigation amounts (4875, 5250, 5625, and 6000 m3 ha−1) were tested. Our results showed that weight loss rates of M 80 and M 100 were 7.21 times and 9.63 times higher than that of M PE , and this degradation process was slowed down with increased irrigation amounts. We attribute this mitigation to changes in soil moisture and the physiological characteristics of the crop. Using film of higher resilience together with higher irrigation amount resulted in more active photosynthesis and fluorescence, especially at the later maize growth stage, and improved maize yield compared to the other degradable film. In addition, the reduction in maize yield caused by the use of biodegradable films could be largely compensated for by applying higher irrigation amounts. Our findings recommend using M 100 with an irrigation amount of 5625 m3 ha−1 for maintaining maize yields while reducing plastic pollution. [Display omitted] • Biodegradable films significantly reduce film residuals in maize field. • Mulching with films and irrigation amounts together control maize growth. • Yield reduction by using biodegradable films was compensated by higher irrigation. [ABSTRACT FROM AUTHOR]

Soil aggregate stability is critical to ensure the provision of agricultural land. Mulched drip irrigation (MDI) is widely used in arid region of northwest China, but the response of soil aggregate stability to soil organic carbon (SOC) and salinity as affected by continuous MDI is still unclear. In this study, we examined four MDI ages (9, 13, 15, and 23 years) of cotton fields that were converted from wasteland (CK, 0 year) and evaluated the impact of MDI age on soil aggregate size distribution, aggregate stability, and aggregate-associated SOC/salinity. The results showed that the proportion of macro-aggregates (>0.25 mm) and aggregate stability (MWD, GMD) initially decreased and then increased as MDI age progressed. As MDI age increased, the concentration of aggregate-associated SOC in all fractions significantly increased, while salt concentration significantly declined. Compared to the CK (0 year), the total SOC stock in cotton fields aged 9, 13, 15 and 23 years increased by −0%, 11%, 17%, and 87%, respectively; whereas the total salt stock decreased by 33%, 68%, 67%, and 76%, respectively. Moreover, due to the significant increase in macro-aggregate content and associated SOC concentration with MDI age, the storage of SOC in older MDI ages (15–23 years) was more reliant on macro-aggregates. Pearson correlation and principal component analysis indicated a negative correlation between salinity and macro-aggregates, aggregate stability, and SOC, while there was a positive correlation among MDI age, SOC, macro-aggregates, and aggregate stability. Based on our findings, we concluded that long-term MDI promotes the formation of macro-aggregates, enhances aggregate stability by reducing soil salinity and increasing SOC stock. • Long-term MDI strongly affects soil aggregate characteristics. • Long-term MDI significantly increased SOC stock and decreased soil salt stock. • SOC and salinity are key factors affecting macro-aggregates formation under MDI. • SOC storage is primarily dependent on macro-aggregates under long-term MDI. [ABSTRACT FROM AUTHOR]

In order to harness the ample solar energy resources and minimize conflicts in drip irrigation schedules, a field experiment was conducted in Xinjiang, northwest China, during 2020 and 2021. The study examined the combined effects of two irrigation timing (daytime - DI and nighttime - NI) and four water temperatures (15, 20, 25, and 30 °C), resulting in eight treatment combinations. The analysis focused on evaluating the impacts of these factors on soil conditions, cotton phenological period, reproductive growth, and fiber quality. Results showed that elevating the irrigation water temperature had a notable impact on soil respiration throughout the different growth stages. The treatment with an irrigation water temperature of 30 °C exhibited a substantial increase in soil respiration, ranging from 17.92% to 45.95%, when compared to conventional irrigation with water temperature at 15 °C. The elevation of irrigation water temperature resulted in notable reductions in soil nitrate and ammonium nitrogen levels. Specifically, the treatment with irrigation water temperature set at 30 °C exhibited an average decrease of 21.69% and 19.27% in soil nitrate and ammonium nitrogen content, respectively, compared to the 15 °C treatment in both years. Nighttime irrigation with increased water temperatures of 20, 25, and 30 °C advanced the onset of the boll opening stage and stimulated the reproductive growth of cotton. Conversely, irrigation with regular water temperature (15 °C) decreased the number of bolls during the early boll-forming period, as well as and the peak number of squares and flowers. However, it resulted in an increased number of bolls during the late boll-forming period. Surprisingly, despite the enhancement in fiber strength and elongation due to water-warming irrigation, it unexpectedly led to a decrease in fiber length and uniformity. Moreover, higher irrigation water temperatures (25 and 30 °C) even resulted in poor levels (> 5.0) of micronaire. Nevertheless, nighttime warming irrigation improved all other fiber qualities except for uniformity. Therefore, when considering the application of water-warming irrigation in arid regions under mulched drip systems, careful selection of irrigation timing and water temperatures is necessary, taking into account the desired fiber quality. This study serves as a valuable technical reference for such irrigation practices. • Water warming promote soil respiration and nitrogen consumption. • Water temperature and irrigation timing significantly affect cotton phenology. • Water warming decreases the fiber quality of cotton. [ABSTRACT FROM AUTHOR]