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Highlights • Biodegradable and plastic mulches were compared in drip irrigated cotton fields. • All mulches were effective in soil water and heat conservation and increasing yield. • Two biodegradable mulches performed similarly to plastic mulch in enhancing WUE. • Commercially available biodegradable mulch can be an alternative to plastic mulch. Abstract Biodegradable mulches are advocated as an alternative to plastic mulches. Here, we carried out an experiment in Xinjiang, an arid region in China, to demonstrate the effects of mulching biodegradable films under drip irrigation on soil conditions and cotton (Gossypium hirsutum L.) yield in 2015 (with less precipitation) and 2016 (with more precipitation). Plastic mulch made from polyethylene (PE) and four types of biodegradable mulch were compared, namely, BD1 to BD4, with different levels of thickness and induction periods. Our results indicated that PE mulch was the most efficient in soil water and heat conservation. Biodegradable mulches performed similarly in warming the soil in both years, which increased topsoil (5–20 cm depth) temperature than no mulching in the cropping season by 0.66 °C and 0.61 °C in 2015 and 2016, respectively. The effect of mulching on increasing soil water storage was stronger in the wet year. The increased soil water storage (0–100 cm depth) by biodegradable mulches than no mulching was 113 mm and 194 mm in 2015 and 2016, respectively. Earlier onset of the phenological events of cotton growth was similar between PE mulch and biodegradable mulches. Mulching shortened the number of days from sowing to cotton maturity by 4 days and 10 days in 2015 and 2016, respectively. Compared with no mulching, biodegradable mulches achieved better performance in enhancing cotton yield and water use efficiency (WUE) in the dry year (916 kg ha−1; 1.85 kg ha−1 mm−1) than in the wet year (568 kg ha−1; 1.22 kg ha−1 mm−1). Although PE mulch resulted in the highest yield, there was no significant difference in WUE between PE mulch and BD1 or BD2. Therefore, some of the commercially available biodegradable mulches can be used as a competitive alternative to plastic mulch to enhance crop yield and control soil pollution. [ABSTRACT FROM AUTHOR]

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]

Preferential flow in soil has a potential impact on the maintenance of the agricultural ecosystem. The aim of this study was to quantify and evaluate the characteristics of preferential flow in drip irrigation cotton fields in Xinjiang. We applied the dye tracer method, addressed the variability in stained images, collected soil samples in the excavated soil profile, and calculated the fractal parameters in four key growth stages of cotton in 2021. According to the dyeing mode, the dyed area ratio tended to keep decreasing from the soil surface; a down movement of points which drastically dropped to zero appeared at pace with the growth of the cotton (from −10 cm to −30 cm). Statistics obtained from the staining images showed that the preferential flow degree was highest at the boll opening stage; no significant difference in non-uniformity emerged from different treatments at the same growing stage (p > 0.05). Conversely, the fractal feature parameters in the active region model probed that the preferential flow degree was developed at the flowering & bolling stage in treatments with opaque oxidation-biodegradable film mulching (B,W), and at boll opening stage with plastic film mulching (P). During the same growth period, a significant difference (p < 0.05) existed between different groups. In comparison, the fractal feature parameter was found more adequate and effective in evaluating the characteristics of preferential flow in drip irrigation cotton fields. This research will provide practical information for the local department to adjust some agronomic measures to reduce the risk of low irrigation water utilization efficiency. • Dyed area ratio had a tendency of keeping decreasing from soil surface. • Finger flow mainly appeared in the soil at the early cotton growth stage. • Macropore flow primarily developed with the maturing stages of the cotton. • Fractal feature parameter was comparatively effective to evaluate the preferential flow. [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]

Integrated with deep learning algorithms, machine vision techniques have emerged as a robust method for the swift and non-destructive assessment of crop moisture status across extensive agricultural landscapes. Within the agricultural sector, where water serves as a crucial resource, especially for cash crops such as cotton, precise monitoring of water status in fields is paramount. This study presents a novel approach for the evaluation of thermal imagery of cotton crops to predict their water status. The research focused on the application of a methodology that harnesses deep learning architectures in tandem with extant local irrigation practices. A considerable dataset, comprising approximately 5200 images, was collected under conditions of submembrane drip irrigation conditions. Cross-validation was employed to evaluate five deep learning models: VGG16, ResNet-18, MobilenetV3, DenseNet-201, and CSPdarknet53 for training and testing purposes. Experimental outcomes indicated that the MobilenetV3 model outperformed other deep learning architectures. It demonstrated exceptional capability in identifying cotton water stress classes, achieving an F1 value of 0.9990, with an average processing time of 44.85 ms. These results underscore the effectiveness of utilizing deep learning algorithms for accurately assessing water stress in cotton under mulched drip irrigation. This establishes a foundational basis for the development of a precise, cost-effective, and real-time monitoring system for the management of water in cotton fields. • The effects of five CNN models for cotton water deficit recognition were compared. • The identification of cotton water deficit under real conditions was realized. • The analysis obtained the most suitable CNN model for actual field use. • This study is helpful to develop a precise irrigation system by machine vision. [ABSTRACT FROM AUTHOR]

Mulched drip irrigation is regarded as an effective water-saving irrigation technique that is adopted widely in dryland regions. However, due to the lack of efficient mulch film recovery, residual plastic film fragments accumulating in soil nowadays pose a risk to agricultural production sustainability. To mitigate the pollution result from polyethylene (PE) film mulching and demonstrate the relationship between soil microenvironment, photosynthetic capacity, yield, and water use efficiency of cotton (Gossypium hirsutum L.) in various mulching practices, a two-year field experiment was carried out to test five mulching practices (sprayable degradable film mulching; biodegradable transparent film with an 80-day induction period mulching; biodegradable transparent film with a 100-day induction period mulching; conventional transparent polyethylene film mulching; no film mulching) in Xinjiang, Northwest China. The results showed that mulching significantly increased soil water content and temperature by 23.83% and 15.01% (average on two years) in topsoil compared to the bare soil surface, associated with a higher plant height, leaf area index, photosynthetic rate and aboveground biomass accumulation. Soil moisture, temperature, and crop height all significantly influenced cotton leaf photosynthetic rate, and soil moisture had the most significant impact (the direct path coefficient was 0.450). The highest cotton yield and WUE were observed in PE film mulching (5480.59 kg ha−1 and 1.35 kg m−3, respectively, average on two years) and the biodegradable transparent film with a 100-day induction period was comparable with PE film in yield increased and reduction of water loss (yield and WUE was 5357.51 kg ha−1 and 1.29 kg m−3, respectively, average on two years). The sprayable biodegradable film also had good wetting and warming effects on soil, but notably, sprayable film performances were still weaker than that in solid films. Compared to solid degradable films mulching, soil moisture, soil temperature, photosynthetic rate, yield, and WUE in sprayable film mulching was decreased by 5.55%, 7.19%, 31.41%, 5.31%, and 8.58% on average, respectively. In general, biodegradable transparent film with a 100-day induction period could significantly improve soil water-heat status, enhance cotton development, reduce water evaporation, increase cotton yield and WUE, which provides a cotton-cultivation option to control residual PE fragments pollution and maintained cotton yield. • Degradable films mulching increased irrigation water availability in Northwest China. • Soil moisture had the greatest impact to cotton leaf photosynthetic rate. • Sprayable biodegradable had a good wetting and warming effects on soil. • The compatibility of water-heat conservation of sprayable film was weaker than solid films. [ABSTRACT FROM AUTHOR]

• Cotton yields were significantly increased by drip irrigation with plastic mulching in oasis region. • Drip irrigation with plastic mulching significantly increased soil moisture and temperature. • Drip irrigation with plastic mulching significantly increased soil CO 2 emissions. • Total CO 2 emissions in narrow rows near drip tape were highest, followed by wide rows and bare land. As the second carbon storage pool, soil is easily influenced by human activities. Mulched drip irrigation is a water-saving irrigation technique used widely in arid and semi-arid regions. However, information about the response of CO 2 exchange to mulched drip irrigation, such as the wetter and warmer soil, is limited. To identify the carbon emissions effects of mulched drip irrigation, we carried out a field experiment using drip irrigation with and without clear plastic mulching during the cotton growing seasons of 2015 and 2016. We monitored the temporal and spatial variation of soil moisture, soil temperature, cotton growth stage, biomass, lint yield, CO 2 emissions, and the relationship between soil respiration rate and soil climate. The results showed that plastic mulching drip irrigation increased soil moisture and soil temperature, especially during the early and middle growth stages of cotton. The soil respiration rate was related positively to the higher soil temperature and moisture conditions promoted by plastic film mulching, although the coefficients of determination were low (R2 were 0.480 and 0.205, corresponding p-value was both 0.000, respectively). The highest value of soil respiration was obtained within the narrow rows under the drip tape, regardless of the practice of mulching or not. The soil respiration rate under plastic mulch in the narrow and wide rows were on average 28.35 % and 22.48 % higher than non-mulched control. Meanwhile, the amount of total CO 2 emissions was significantly increased by 25.34 % and 28.90 % in these same rows, respectively (p-values were 0.006 at narrow rows and 0.010 at wide rows in the first year, and 0.000 at same rows in the second year). The differences of CO 2 emission in the bare soil was not significant between mulched plots and non-mulched control (p-values were 0.757 and 0.918 in the first and second growing seasons, respectively). In addition, plastic mulching significantly improved the biomass and yield of cotton, by 61.49 % and 12.83 % on average (p-values were 0.034 and 0.039 in 2015, 0.024 and 0.032 in 2016), respectively. The results indicate that the application of drip irrigation under plastic mulch could increase soil water content and temperature, promote cotton growth, and improve lint yield. However, it may also lead to increased CO 2 emissions, which can intensify the warming of the climate. [ABSTRACT FROM AUTHOR]

Imbalanced water and fertilizer systems have limited the yield and quality of grapes in extremely arid areas. The combined application of organic (OF) and inorganic fertilizers (CF) has been proven to be one of the practical approaches to improving yield and quality. Nevertheless, very few studies have focused on the irrigation amount in organically fertilized and drip-irrigated grapes. Hence, in this study, four combined application ratios of organic and inorganic fertilizers (70%OF + 30%CF, 50%OF + 50%CF, 30%OF + 70%CF, and 0%OF + 100%CF), and four irrigation amounts (630, 675, 720, and 765 mm) were set coupling in a two-year field experiment. Generally, under four irrigation levels, combined organic-inorganic fertilizers increased soil nutrients and improved seedless white grape growth, yield, and quality. The results of the combined fertilizer application treatments showed that the content of available nitrogen (55.97–102.60%), available phosphorus (49.41–124.74%), and available potassium (60.70–124.33%) in soil increased significantly compared with those values under a single application of inorganic fertilizer. In addition, the combined application increased the length of new shoots and leaf midribs (grapes) by 3.16–11.88% and 7.35–15.15%, respectively; this application mode also significantly enhanced transpiration rate (Tr), stomatal conductance (Gs), and net photosynthetic rate (Pn). Furthermore, the grape yield increased by 6.68–19.12%, and the fruit quality notably improved (except for the index of fruit shape). Under the four irrigation amounts, two-year average yields were reported as 17.53, 20.60, 23.31, and 22.71 kg/ha, respectively. Additionally, we used four evaluation methods to assess the fruit quality and compared their correlations with the comprehensive evaluation model. And we concluded that the principal component analysis method (PCA) is best suited for evaluating drip-irrigated grapes' quality. Then, we applied the PCA to seek proper irrigation management; the results displayed that a suitable irrigation amount of 720 mm and the ratio of organic-inorganic application of 50% organic fertilizer + 50% inorganic fertilizer is recommended. However, further research is required to investigate the effects of soluble and complete organic fertilizers application on drip-irrigated grapes. • Irrigation amounts combining organic-inorganic fertilizers affect the grape quality and yield. • Different statistical methods are applied and compared for evaluating drip-irrigated grapes quality and yield. • Irrigation amount 765 mm with 50% organic + 50% inorganic fertilizer is recommended for grapes planting. [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 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]

Utilizing brackish water with drip irrigation technology, due to its precise water control alleviates the secondary soil salinization, and improves crop yield and quality, which offers sustainable agricultural development opportunities in saline areas. However, the complex characteristics of brackish water increase the risk of drip irrigation emitter clogging, which inhibit its promotion and adoption. It is necessary to find out the dominant water quality ions that lead to emitter clogging under multiple ion interactions when using brackish water under multiple ion coexistence conditions. Thus, the in-situ pilot research was conducted to study the emitter clogging mechanism using brackish water collected from 16 different salt-alkaline regions. A comprehensive evaluation with the consideration of 11 water quality ions on emitter clogging were conducted. Results showed that the degree of emitter clogging gradually increased in the first 40 days of irrigation, hereafter started an accelerated reduction until the days 64 of brackish water application. Spearman correlation and structural equation modelling were used to identify the main factors contribute to emitter clogging. And results indicated that calcium fouling (CF) and silica fouling (SF) were the major fouling minerals in the emitter flow channels. Ca2+, CO 3 2-+HCO 3 -, pH, total hardness (TH), and zeta potential (ZP) were the key water characteristics leading to emitter clogging. These factors directly affected CF and SF, while also affecting the Mg2+, Mn2+, Cu2+, and other water quality factors which indirectly enhanced the CF and SF. Thereafter a few water quality control strategies were proposed based on emitter clogging and soil salinization mitigation. This study identified the key water quality ions that induce drip irrigation emitter clogging when using brackish water, provided solid support for solving the clogging issue, and promoted the high-efficient utilization of brackish water in saline areas. • Brackish water drip irrigation performance in saline areas was studied. • Main types and formation of fouling in drip irrigation systems were analyzed. • Critical water quality ions for brackish water utilization were identified. • Control strategies considering irrigation and soil environment were proposed. [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]

Soil microorganisms are key drivers of soil nutrient cycling and agroecosystem sustainability. Despite their critical roles in soil evolution processes, the variation of soil microbial communities in cotton fields with different years of practicing mulched drip irrigation remains poorly understood. The objectives of this study were to investigate the effects of different years of mulched drip irrigation (i.e., CK, 11, 13, 15, and 21 years) on soil microbial communities and soil properties in cotton fields in an oasis by using high-throughput sequencing of the microbial 16 S/ITS gene. The results showed that soil EC decreased significantly after mulched drip irrigation and the lowest value occurred in 21-year treatment, decreased by 74.43%. Soil organic carbon, available nitrogen, available phosphorus and available potassium increased significantly with the length of years under mulched drip irrigation. The abundance of dominated bacterial phyla (Actinobacteria , Bacteroidetes, and Rokubacteria) significantly varied among different years of mulched drip irrigation, and no significant change was found in soil fungal community at the phyla level. The abundance of dominated fungal genera Cephalotrichum (21.82–68.96%) decreased significantly with irrigation years extension. Non-metric multidimensional scale analyses (NMDS) showed that soil bacterial and fungal communities significantly differed among different treatments (P = 0.001). The more positive co-occurrence relationships of bacteria to fungi, and the highest Shannon and lowest Simpson values were observed in the 13-year mulched drip irrigation. The abundance of bacteria and fungi was significantly correlated with soil EC, total nitrogen, total potassium, and soil organic carbon. Our results indicated that long-term mulched drip irrigation affected the structures and interactions of microbial communities in cotton fields by reducing soil salinity and regulating the soil nutrient concentrations, and 13-year mulched drip irrigation was capable of enhancing soil microbial diversity in this region. • Applying time of mulched drip irrigation significantly affected the soil bacterial and fungal communities characteristics. • 13-year mulched drip irrigation improves not only soil fertility but also soil microbial diversity in arid oasis regions. • The long-term mulched drip irrigation affected the microbial communities by changing soil salinity and nutrient concentrations. [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]

Brackish water drip irrigation (BWDI) is an effective application to overcome the water scarcity issues and achieve sustainable agriculture development. However, emitter clogging and soil salinization is inevitable issue in BWDI, eventually threatening the environmental pollution and sustainable application of drip irrigation systems. Therefore, this study experimentally assessed the anti-clogging efficacy of compounding appropriate types of humic acid (HA) with conventional fertilizer in BWDI systems (BWDIs). Humic acid nitrogen (HAN), humic acid phosphate (HAP), humic acid potassium (HAK), were compounded with conventional fertilizers. Our results revealed, compared with conventional fertilizer (CK) the HA treatments indirectly affected the precipitates and particulate fouling by absorbing the active functional groups, and directly decreased the pH, calcium and magnesium contents in brackish irrigation water. Accordingly, HA compound fertilizer significantly reduced the fouling content of drip irrigation system, and the anti-clogging effect became better with the increase of HA application. Thus, based on better anti-clogging performance and minimum fertilizer costs, our results suggested, the HAN+HAK integrated fertigation could be an effective selection for BWDIs, which significantly enhanced the average discharge ratio and Christiansen coefficient of nutrient uniformity in BWDIs by 16.0% and 19.0% respectively. These results might provide a new guideline for the successful application of HA compound fertilizer in BWDIs, to increase the drip irrigation anti-clogging ability and overcome the agricultural non-point source pollution issues. • Effects of humic acid compound fertilizer on fouling of drip irrigation systems were analyzed. • Humic acid compound fertilizer reduced the precipitate and particulate fouling. • Compound fertilizer HAN+HAK are recommended in brackish water drip irrigation. [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]

Cultivation after converting saline and alkaline wasteland to agricultural land is usually accompanied by accelerated soil salinization. There is general agreement that freezing-thawing process plays a crucial role in soil salinization in mostly cold-arid agricultural areas, which leads to the impoverishment of soil productivity. To investigate the migration characteristics of soil salinity in saline-sodic cotton field with different reclamation time in non-irrigation season, we examined the soil bulk, total porosity, and spatial and temporal migration of soil salinity in winter in an oasis agroecosystem of northern Xinjiang, China. Experimental plots include a saline-alkali wasteland as control and cotton fields under four age categories (cultivation start years were 1998, 2006, 2008, and 2012, respectively). The results showed that converting saline-alkali wasteland to cotton land significantly decreased soil bulk density but increased total soil porosity, especially at 0–40 cm. Conversion significantly decreased soil salinity at 0–200 cm soil depths, with a greater decrease in cotton land after relatively longer time of cultivation. After freezing-thawing process, soil bulk density decreased 4.87% on average, and total porosity increased 5.98%. Soil salt dynamics showed that there were two stages in salt accumulation. Firstly, soil salt storage increased at 0–100 cm depth but decreased at 100–200 cm depth during freezing period; Secondly, rapid increase of salt storage appeared at late thawing period. In addition, salt accumulation positively correlated to initial salt content and bulk density, but negatively correlated to total porosity. At springtime, cotton land with short-term cultivation was desalination comparing with pre-freezing, but salt accumulation occurred after long-term cultivation. These results highlighted that long-term cultivation with mulched drip irrigation decreased soil salinity in the 0–200 cm soil profiles, but freezing-thawing process induced soil salinization which poses a potential risk to agricultural sustainability. • Converting wasteland to farmland decreased soil bulk density and increased total porosity. • Long-term cotton cultivations with drip irrigation significantly decreased soil salinity. • Freezing-thawing action decreased soil bulk density and increased total porosity. • Freezing-thawing action poses a potential risk to agricultural sustainability. [ABSTRACT FROM AUTHOR]