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When crop roots are in a low oxygen environment for a long time, it will lead to a series of problems. To improve soil oxygen conditions, a method of oxygenation irrigation is increasing the dissolved oxygen (DO) concentration in irrigation water. However, its application effect in a mulched drip irrigation system is not clear. In this study, a field experiment was conducted in Xinjiang to investigate the actual effect of oxygenation irrigation in field planting. We set up mechanical oxygenation (AO), venturi oxygenation (VO), and four chemical oxygenations with different DO concentrations (CO1–4). The results showed that physical oxygenation (AO, VO) was limited by the saturated DO of irrigation water. Compared with venturi oxygenation, mechanical oxygenation could reach the saturated DO faster and had higher stability of DO concentration during single irrigation. The chemical oxygenation was not limited by the saturated DO. The maximum DO in irrigation water would also increase with the increase in the amount of oxygen enhancer, but it needed more reaction time than the physical oxygen to reach a stable state. The oxygenated water would be affected by water temperature and delivery distance in the mulched drip irrigation system, resulting in the continuous decline of DO during the irrigation process. For those oxygenated water with saturated DO under different oxygenation methods (AO, VO, and CO1), when they entered the soil, there was no significant difference in the changing trend of DO. In an irrigation process, with the increase of DO, the actual oxygenation efficiency in the soil also increased. The DO concentration of irrigation water was increased from 3.9 mg L−1 to 9.1 mg L−1, and 10 times of irrigation was carried out during the crop growth period, then soil oxygen could be increased by an average of 6.72∼6.89%. By increasing the DO of irrigation water, the soil oxygen condition of mulched drip irrigation can be improved. Under the condition of saturated DO, each oxygenation irrigation had no significant impact on the soil physical and chemical properties. After two years of irrigation, the chemical oxygenation using sodium percarbonate had increased the soil EC, pH, and Na+ content, which means slightly intensified the soil salinization. • The DO concentration of water in drip irrigation tube is inversely proportional to conveyance distance and water temperature. • The DO concentration of water increases from 3.9 mg L−1 to 9.1 mg L−1, the soil oxygen can be average increased by 6.7–6.9%. • Chemical oxygenation irrigation has the risk of aggravating soil salinization. [ABSTRACT FROM AUTHOR]

In order to alleviate the shortage of water resources for cotton (Gossypium hirsutum L.) planting in Xinjiang of China, a reasonable amount of nitrogen application under brackish water irrigation was sought. A two-year field experiment was conducted to investigate the effects of nitrogen application rate and irrigation water salinity on seed cotton yield, nitrogen partial factor productivity and fiber quality in Xinjiang under mulched drip irrigation in 2019 and 2020. In this study, we selected four nitrogen application rates (i.e., 100, 200, 300, and 400 kg N ha−1, respectively) and three irrigation water salinity (i.e., 1, 3, and 5 g L−1, respectively). Our results showed that nitrogen application rates and irrigation water salinity significantly affected the seed cotton yield, nitrogen partial factor productivity, micronaire, fiber length, fiber strength, uniformity index and elongation. As the salinity of irrigation water increased, seed cotton yield and nitrogen partial factor productivity increased first and then decreased, micronaire decreased, but fiber length, fiber strength, uniformity index and elongation increased. Moreover, seed cotton yield, micronaire, fiber length, fiber strength, uniformity index and elongation increased first and then decreased, and nitrogen partial factor productivity decreased with the amount of nitrogen application. The optimal combination of nitrogen application rate and irrigation water salinity were 200 kg N ha−1 and 5 g L−1 by principal component analysis. We concluded that the normalized relative value of seed cotton yield and comprehensive evaluation value was 0.85, when the nitrogen application rate and the irrigation water salinity were 197.04 ⁓ 237.94 kg N ha−1 and 3.60 ⁓ 3.88 g L−1, respectively. • Irrigation salinity affected yield and quality of cotton. • Cotton yield increased first and then decreased with increasing irrigation salinity. • There was no difference among micronaire, fiber length, strength, uniformity and elongation. • Yield and quality of cotton reached the maximum together as affected by irrigation salinity. [ABSTRACT FROM AUTHOR]

Biodegradable film (BF), as a superior substitute for traditional polyethylene film (PF), has experienced a consistent increase in China. However, a significant research gap persists regarding the utilization of BF in assessing farmland carbon balance. This experiment examined the responses of maize growth, yield, irrigation water productivity (IWP), CO 2 emissions, and field net carbon sequestration (NCS) to two BF types (BF 1 , 100-day induction period, and BF 2 , 80-day induction period), and PF, and three irrigation amounts (I 1 , I 2 , I 3 : 5250, 5625, and 6000 m3 ha–1), by conducting a two-year (2019–2020) field trial in a typical arid and semi-arid region of China. The results indicated that biodegradable film mulching (BFM) negatively affected maize growth, resulting in reduced yield and IWP. Especially under the I 1 irrigation level, the biodegradable film reduced maize yield by 6.26%–13.99% and IWP by 6.64–13.85%. Notably, in the I 2 irrigation level, BF 1 mulching had a comparable impact on maize yield and IWP to that of PF. Additionally, the increase in irrigation amounts exerted a more pronounced promoting effect on maize total biomass than on yield and IWP. Concerning carbon balance, short-term BF application resulted in reduced CO 2 emissions (5.74–6.30% under BF 1 and 9.27–12.37% under BF 2), without any significant impact on NCS in cropland. Taking into account the economic value of maize and farmland ecology, we recommended utilizing irrigation amounts of 5625 m3 ha–1 for BF application in arid areas, while opting for a BF with a longer induction period whenever feasible. • Biodegradable film mulching reduces maize yield and irrigation water productivity. • Biodegradable film mulching significantly decreases soil CO 2 emissions. • Increasing irrigation compensates for yield loss due to biodegradable film mulching. • Biodegradable film with a 100-day induction period is an ideal covering material. [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]

In the Yellow River Delta, soil salinization and river sediment are the two factors influence on economic growth. A large area of salinization reduces crop yields and dredged river sediment increases management costs. This study evaluated the effects of applying sediments under different levels of irrigation on salinity leaching for improving field productivity. A three-year field experiment (from June 2017 to June 2020) was conducted by considering three levels of sediment application:a control (no sediment added, S1), 30▒mm ha−1 (S2) and 60▒mm ha−1 (S3), and three levels of irrigation water: 290▒mm (90▒mm maize + 200▒mm wheat, W1), 385▒mm (120▒mm maize + 265▒mm wheat, W2) and 480▒mm (150▒mm maize + 330▒mm wheat, W3). The results exhibited that soil leaching rate was up to 66.3 % under 60▒mm ha−1 sediment application and 385▒mm irrigation after three wheat-maize rotation cultivation. This irrigation and sediment applied strategy achieved the effect of leaching salt, saving water and increasing grain yields. The mean yield of wheat and maize in sediment application and irrigation treatment was 18.3▒t ha−1 in three-year experiment which was significant bigger than the control. Thus, it is a technically feasible and friendly sustainable approach for salinization soil development in the Yellow River Delta. • Coupling effects of irrigation and sediment application on soil physical properties and grain yield. • Response of soil salinity to sediment application improves understanding of underlying mechanisms involved. • Sediment application at a rate of 60▒mm ha−1 was optimal to enhance grain yield. [ABSTRACT FROM AUTHOR]

Water scarcity and deficiency of trace elements (e.g., Cu and Mn) in soils of arid and semi-arid areas are major constrains to crop growth and development. The application of brackish water drip irrigation system (BWDIs), coupled with trace elements, is probably an effective way to solve this problem. However, fouling problems caused by trace elements in BWDIs were inevitable. Therefore, this paper evaluates the mechanism of different types of trace element chelated fertilizers on the fouling of emitters in BWDIs by using long-period, high-frequency periodic flow monitoring and mineral fraction analysis. The influence of chelated fertilizers such as copper (EDTA-Cu) and manganese (EDTA-Mn), and traditional micro-fertilizers copper sulfate (CuSO 4) and manganese sulfate (MnSO 4) on emitter fouling in BWDIs were investigated. Results suggested, compared with CK, the EDTA-Cu effectively alleviated the emitter fouling, increasing the average discharge ratio (Dra) and Christiansen coefficient of uniformity (CU) by 21.0%− 28.9% and 36.7%− 67.6%, respectively. Due to the strong adsorption ability, EDTA-Cu adsorb the Ca2+ and Mg2+ in BWDIs, which enhanced the structural stability, reduced the flocculation and deposition ability in the fouling, and indirectly reduced the content of calcium and silica fouling. In addition, compared with CK, the EDTA-Mn significantly aggravated the emitter fouling in BWDIs, decreasing the Dra and CU by 18.2%− 22.5% and 24.5%− 43.1% respectively. EDTA-Mn directly increased the content of Ca2+ and Mg2+ in BWDIs due to strong flocculation, which destroyed the morphology of EDTA-Mn chelates and indirectly increased the content of calcium silica fouling (calcite, muscovite, k-feldspar, dolomite and chlorite), thus reduced the anti-clogging ability of BWDIs. Considering these results, this study does not recommend the application of EDTA-Mn for manganese fertilizer in BWDIs. This study provides a new perspective on the rapid application of micronutrient fertilization in BWDIs, with potential implications for sustainable development in arid and semi-arid areas. • Effect of manganese and copper fertilizers on fouling of drip irrigation systems was analyzed. • EDTA-Cu fertilizer significantly reduced calcium and silicate fouling in the irrigator runners. • Use of EDTA-Cu fertilizer in brackish water drip irrigation is strongly recommended. [ABSTRACT FROM AUTHOR]