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Capillary water, serving as a crucial intermediary between groundwater and crop root layer moisture, is important for both soil retention and crop utilization. To investigate the effect of mulched drip irrigation (MDI) on upward capillary water in cotton fields with different application years (0, 10, 14, 18, 20, and 24 years) in the saline–sodic region of Northwest China, an indoor soil column test (one-dimensional capillary water rise experiment) was conducted. The results showed that the wetting front transport law, capillary water recharge, and wetting front transport rate over time exhibited an increasing trend in the early stages of MDI application (10 and 14 years), peaking at 18 years of application, followed by a decreasing trend. The relationship between the capillary water recharge and rising height was fitted based on the Green–Ampt model, and their slopes reveal that 14 and 18 years of MDI application required the largest amount of water per unit distance, indicating an excellent water-holding capacity beneficial for plant growth. Conversely, 0 years required the smallest amount of water per unit distance. Based on the movement characteristics of upper capillary water, we confirmed that the MDI application years (0–18 years) improves soil infiltration capacity, while the long-term application years (18–24 years) reduces groundwater replenishment to the soil. Furthermore, the HYDRUS-1D model was employed to simulate the capillary water rise process and soil moisture distribution under different MDl application years. The results showed an excellent consistency with the soil column experiments, confirming the accuracy of HYDRUS-1D in simulating the capillary water dynamics in saline–sodic areas. The results would provide suggestions to achieve the sustainable development of long-term drip-irrigated cotton fields. [ABSTRACT FROM AUTHOR]

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]

BACKGROUND: Cotton (Gossypium hirsutum L.) is the fiber crop most widely cultivated globally and one of the most important commercial crops in China, irrigation is closely related to the growth of cotton. A water temperature for irrigation that is too low or too high inhibits cotton growth. Poor irrigation timing results in water and nutrient deficiencies that reduce cotton yield. Therefore, it is necessary to determine the appropriate irrigation timing and water temperature. METHOD: We conducted an experiment in an arid region of north‐western China to assess the effects of irrigation timing and water temperature on soil temperature and the photosynthetic characteristics, biomass, total nitrogen (N), and seed cotton yield. Two irrigation times (daytime and nighttime) and four water temperatures (15, 20, 25, and 30 °C) were combined into eight treatments. RESULTS: Our results showed that water warming and nighttime irrigation improved the photosynthesis, biomass, N concentration (the proportion of total N weight in the plant biomass, in g kg−1), N content (the mass of total N, in g plant−1), and cotton yield. The optimal water temperature range for photosynthesis was 25.7–28.7 °C. Water warming also boosted the biomass allocation to the stem and increased the N allocation to the stem and leaf. Nighttime irrigation enhanced these phenomena. Water warming also increased the number of bolls per plant but reduced the single boll weight, increasing the seed cotton yield by 5.88–11.46%. At the same water temperature, irrigation during the night increased the number of bolls per plant and the single boll weight, improving the seed cotton yield by 2.95–4.31%. Among them, NI25 (nighttime irrigation with 25 °C water temperature) increased the yield by 14.13–14.90% compared with CK (daytime irrigation with 15 °C water temperature), which offers the best combination for increasing the yield. CONCLUSION: Our study clarifies the optimal irrigation timing and water temperature for cotton production under drip irrigation with film mulching, providing valuable information for improving the cotton yield in arid areas with temperate continental climate. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The sustainable development and utilization of saline-alkali land are closely related to holding fast the minimum cultivated land area of China. The change of soil salt in cotton field under long-term mulched drip irrigation (MDI) is connected with the development of the national cotton industry. From 2015 to 2019, five cotton fields with different applying years of MDI, which were reclaimed in 2004, 2008, 2010, 2012 and 2015 respectively and were saline-alkali wasteland before, were monitored continuously in the Manas River irrigation area of Xinjiang. By means of continuous location monitoring and spatial–temporal variability (For example, the monitoring data of cotton fields under MDI in 2004, 2008, 2010, 2012 and 2015, and in the year of 2015 were counted as 12, 8, 6, 4 and 1 years, respectively), the spatial–temporal variations of soil salt and ions in cotton field with 1-16a MDI technology were presented. The cotton growth characteristics and its main influencing factors were also analyzed in the study. The results showed that saline-alkali cotton field experienced changed from intensive saline soil to moderate saline soil and finally to non-saline soil under long-term MDI. The change of soil salt and the response of cotton growth to soil salt were divided into three typical stages. Firstly, soil desalinated rapidly in 1-4a MDI cotton field, which the annual average desalination rate was 24.93% in 0–100 cm soil layer (root zone). Additionally, the survival rate of cotton rocketed from 1.48% to 42.04%, and yield increased sharply from 72.43 kg ha−1 to 3075.90 kg ha−1. Soil desalination was lower in 5-11a MDI cotton field, which the annual average desalination rate was 10.92% at the root zone. The annual survival rate and yield of cotton increased by 6.26% and 5.18%, respectively. After 12a MDI, the soil salt in cotton field tended to be generally constant, which the average salt content in root zone was less than 2.49 g kg−1. The survival rate of cotton was stable above 90.39%, and the yield per unit area exceeded 5401.32 kg ha−1. Ions, sodium absorption ratio and Cl− and SO42− equivalent ratio (CSER) in cotton soil also decreased with the extension of MDI. Salt composition changed year by year, but the type of intensive saline soil had always been chloride-sulphate solonchak (0.2 < CSER < 1). In practice, with a higher irrigation quota and ideal irrigation water quality, the soil salt environment of saline-alkali soil MDI cotton field had developed in favor of cotton growth in an oasis irrigation area. However, this management practice caused between 124.21–143.61 mm of water resources waste. Therefore, we should further enhanced the consciousness of water-saving and implemented quota management in practice. [ABSTRACT FROM AUTHOR]

• Four biodegradable films were tested to replace PE films in cotton fields under mulched drip irrigation. • Film degradation, soil salinity, residue film accumulation, yield, and WUE were compared. • Degradation process and accumulation of residual film were different between tested films. • Thicker PBAT films and PE films performed similarly in improving cotton yield. • Due to the least accumulation of residual film and highest yield, thicker PBAT films were recommended. To alleviate soil pollution caused by mulching polyethylene (PE) films that are non-degradable and non-recoverable, we evaluated different biodegradable (BD) films (starch-polymer, polybutyrate adipate terephthalate or PBAT, and butylene succinate-co-butylene adipate or PBSA) as alternatives to PE films for mulched drip irrigation in a cotton (Gossypium hirsutum L.) field in Xinjiang, the largest cotton-planting region in China. Film degradation, soil salinity, residue film accumulation, cotton yield, and water use efficiency (WUE) were compared between BD and PE films in two consecutive years (2015–2016). We found that the accumulation of residual film was significantly stronger in plots covered by PE films than by BD films. At the early stage of cotton growth, BD and PE films performed similarly in conserving water in topsoil (0–40 cm depth). Degradation of BD films initiated 40–60 days after sowing. Thus, at the late stage of cotton growth, PE films remained intact and were more effective than BD films in wetting the soil. Due to the drier soil, soil salinity in plots covered by BD films was higher than those by PE films. PBAT films showed a slower degradation process than PBSA and starch films under the mulching condition but degraded more completely after buried in soil. After mulched drip irrigation was managed for two years, cotton yield showed no significant difference between plots with PE films (5722 kg ha−1) and those with thicker PBAT films (5699 kg ha−1). However, mulching PE films resulted in a significantly higher WUE than BD films. Therefore, we suggest thicker PBAT films (with the highest yield and WUE and the lowest accumulation of residual film) as potential alternatives to PE films to improve cotton yield and control soil pollution under mulched drip irrigation. [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]

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]

Xinjiang is one of the most prolific tomato-planting areas in China. Here, we carried out a two-year (2017–2018) field experiment in Xinjiang to study the effects of different nitrogen (N) application rates on the spatial distribution of water and salt in the root zone, as well as their impacts on the yield and quality of tomatoes under mulched drip irrigation. The ideal ranges of N application rates for tomato yield and quality were examined under different salinity levels. Results indicated that soil water content and salinity increased with soil depth. Soil water content was closely related to soil salinity but not to N. Among the tested application rates, tomato yield was highest under the medium-high N (225–300 kg/ha) and low salt (4 g/kg) treatment. Under the highest salt level (10 g/kg), the low nitrogen treatment (150 kg/ha) was better than the high N treatment (300 kg/ha) at boosting tomato yield. Moreover, we found that salinity had a stronger effect on tomato quality than N. Based on these results, we were able to recommend ideal ranges for N (155–201 kg/ha) and salt (3.56–5.59 g/kg) while both are present in the soil. [ABSTRACT FROM AUTHOR]

Processing tomato is one of the most important economic crops in Xinjiang, China, which was constrained with severe water shortage and extreme arid climate. Alternate partial root-zone irrigation (APRI) may provide an effective way to increase irrigation water use efficiency (iWUE) without yield reduction. However, limited studies concerned about applying APRI in processing tomato plantation have been done, especially combined with drip irrigation to further control the irrigation and improve iWUE. Therefore, the two-year pot experiments were conducted to study the effects of different irrigation treatments, including three APRI treatments (irrigation quota of 67.5, 51.6, and 43.7 mm, respectively), fixed partial root-zoon drip irrigation (FPRI, 67.5 mm) and conventional drip irrigation (CDI, 67.5 mm). The results indicated that APRI was an appropriate irrigation method in processing tomato plantation in arid desert area such as Xinjiang, as high irrigation quota of APRI (APRIH) significantly improved its yield without fruit quality reduction in comparison with those of CDI. However, the yield without fruit quality of FPRI significantly decreased. Even if the irrigation quota of APRI decreased to the medium level (APRIM, 51.6 mm), iWUE by increased 31.8–32.7% on the contrary, as irrigation water was saved by 23.6%; while keeping the yield and fruit quality. Therefore, APRIM is recommended for processing tomato plantation in arid northwest China, to increase plant growth, fruit quality, yield, and iWUE synergistically. [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]

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 the agricultural zones of the arid Xinjiang region of China, reducing irrigation is mandatory. However, irrigation affects the composition and diversity of the soil bacterial community which is vital to crop yield. To the best of our knowledge, very little research has been conducted on the relationships among the soil bacterial community, irrigation method, and yield as well as their underlying in jujube agroecosystems. Here, we investigated the soil physicochemistry and bacterial communities in jujube fields subjected to drip irrigation (DI) and traditional flood irrigation (FI), and their associations with yield at the flowering and fruit set (FFS) and end-of-growth (EG) stages. Under DI, the jujube yield was 8712.00 ± 24.54 kg/hm2, which was 7.64% higher than that obtained under FI (8094.33 ± 43.67 kg/hm2). DI increased the relative soil bacteria community diversity by decreasing the moisture content and increasing the nutrient levels in the soil. DI also transformed the soil bacterial community so that Bacteroidota predominated at the FFS stage and the probiotics Chloroflexi and Firmicutes predominated at the EG stage. A co-occurrence network analysis showed that DI created stable complex Soil bacteria communities in jujube fields, Though Dependentiae and Deferriberota had low relative abundance, they were nonetheless key nodes in the soil bacterial community network. A neutral community model (NCM) revealed that stochastic processes drove the soil bacterial community assembly whereas DI promoted deterministic processes by regulating the soil moisture content and nutrient levels. Partial least squares path modeling (PLS-PM) disclosed that DI affected the soil bacterial community structure by decreasing the moisture content (−0.342 **) and increasing the nutrient levels (0.557 **) in the soil. The PLS-PM also demonstrated that the observed change in the soil bacterial community structure was the main reason for the increase in jujube yield (1.098 **). The present work provides insights into the mechanisms underlying the correlations between the soil bacterial community and crop yield in response to changes in the irrigation method. • Drip irrigation regulates the levels of soil moisture and nutrients. • Drip irrigation of soil moisture and nutrients drive the transformation of Bacteroidota to Chloroflexi and Firmicutes. • Dependentiae and Deferriberota with low relative abundance also the key species. • DI induced a small decrease in stochastic assembly for soil bacterial community. • DI increased the jujube yield (8712 kg/hm2) mainly by bacterial composition. [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]