Drip irrigation under plastic mulch is widely used in Xinjiang, Northwest China. It can not only save water, but also reduce nutrient loss and improve fertilizer utilization. However, it is not clear whether the leaching occurs or not, what is the leaching amount? What is the relationship among fertilization, irrigation regimes, loss, cotton absorption, and cotton field under different fertilization and irrigation management under drip irrigation? Studying these issues not only provides reference for the formulation of fertilization and irrigation systems, but also is of great significance for reducing non-point source pollution. A long-term positioning experiment was conducted from 2009 to 2012 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (Gossypium hirsutum L.) under different N fertilizer and irrigation amounts. The treatments were designed comprising Control (CK,0 N, 0 P, and 0 K with an irrigation of 480 mm) and the following three other treatments: (1) Conventional fertilize and irrigation (CON, 357 kg N hm^–2, 90 kg P hm^–2, 0 kg K hm^–2, and irrigation of 480 mm); (2) Conventional fertilization and Optimizing irrigation (OPT, 357 kg N hm^–2, 90 kg P hm^–2, 62 kg K hm^–2, and irrigation of 420 mm); and (3) Optimizing fertilization and irrigation (OPTN, 240 kg N hm^–2, 65 kg P hm^–2, 62 kg K hm^–2, and irrigation of 420 mm). The results found that the leaching would occur in arid area under drip irrigation. The loss of total N, NH₄⁺, P, N and P loss coefficient was higher under conventional fertilize and irrigation treatment while the loss of NO₃^- was higher under conventional fertilization and optimizing irrigation treatment. The correlations among N, P absorption by cotton, loss of NH₄⁺ and total phosphorus were quadratic function. The total nitrogen loss and cumulative nitrogen application was lineally correlated. The loss of NO₃^- and cumulative nitrogen application was exponential. The nitrogen and phosphorus absorption by cotton under conventional fertilization and optimizing irrigation treatment was 24.53% and 35.86% higher than that in conventional fertilize and irrigation treatment, respectively. The cotton yield under conventional fertilization and optimizing irrigation treatment obtained higher than that in other three treatments. Therefore, the conventional fertilization and optimizing irrigation treatment was the optimal management of water and fertilizer in our study. These results demonstrate that reasonable water, nitrogen and phosphorus fertilize could not only effectively promote the absorption of nitrogen and phosphorus, but also reduce nitrogen and phosphorus losses under drip fertigation and plastic mulching.

Drip irrigation systems are becoming more and more mature and are now widely used to improve crop yield and nitrogen use efficiency in Xinjiang, NW China. However, it is not known if leaching is occurring or not and whether leaching will harm the water environment following N fertilization and drip irrigation. The purpose of our study was to estimate the leaching volumes, nitrogen losses, forms of nitrogen losses, and nitrogen loss coefficients under different N fertilization, P fertilization, K fertilization and irrigation regimes. A long-term field experiment was conducted from 2009 to 2015 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (Gossypium hirsutum L.) being grown under different N fertilizer and irrigation regimes. The treatments were designed comprising 0 N, 0 P, and 0 K with an irrigation of 480 mm as the control(N₀P₀K₀W₄₈₀) and the following three other treatments: (1) 357 kg N·hm⁻², 90 kg P·hm⁻², 0 kg K₂O hm⁻², and irrigation of 480 mm (N₃₅₇P₉₀K₀W₄₈₀); (2) 357 kg N·hm⁻², 90 kg P·hm⁻², 62 kg K·hm⁻², and irrigation of 420 mm (N₃₅₇P₉₀K₆₂W₄₂₀); and (3) 240 kg N·hm⁻², 65 kg P·hm⁻², 62 kg K·hm⁻², and irrigation of 420 mm (N₂₄₀P₆₅K₆₂W₄₂₀). The results showed the following: (1) the leaching volume was determined by nitrogen fertilization, phosphorus fertilization, and the irrigation amount. In general, the leaching volume was highest under treatment N₃₅₇P₉₀K₀W₄₈₀. (2) The nitrogen loss was highest under treatment N₃₅₇P₉₀K₀W₄₈₀. (3) Nitrate nitrogen (NO₃^–) was the main form of nitrogen lost, followed by ammonium nitrogen (NH₄⁺). (4) The annual nitrogen loss coefficients followed the order of: N₃₅₇P₉₀K₀W₄₈₀ > N₃₅₇P₉₀K₆₂W₄₂₀ > N₂₄₀P₆₅K₆₂W₄₂₀ > N₀P₀K₀W₄₈₀, with values of 0.85, 0.55, 0.30, and 0, respectively. The leaching volume, nitrogen loss, nitrate nitrogen, ammonium nitrogen, and annual nitrogen loss coefficient were lowest under the N₂₄₀P₆₅K₆₂W₄₂₀ treatment, except in the N₀P₀K₀W₄₈₀treatment. These results demonstrate that optimizing the management of water and nitrogen (N₂₄₀P₆₅K₆₂W₄₂₀ treatment) can effectively reduce nitrogen losses under drip fertigation and plastic mulching.

Soil pollution caused by plastic residues containing additives (e.g. phthalic acid esters (PAEs)) is ubiquitous and has become a global concern. However, the distribution, accumulation, and potential risks associated with PAEs in agricultural soils have not been fully explored. This study quantified the types, concentrations, and distribution patterns of common PAEs in 29 agricultural soil samples collected from the Xinjiang Oasis, China. The results indicated that no significant variation in PAE concentrations across the oasis farmlands in Xinjiang. The PAEs were predominantly concentrated in the topsoil layer (0-20 cm), with an average concentration of 102.3 μg/kg, with some migration observed to the deeper soil layer (20-40 cm). The most abundant PAEs detected were Di (2-ethylhexyl) phthalate (DEHP), diisobutyl phthalate (DIBP), and diethyl phthalate (DEP), which accounted for 49.82 %, 23.74 %, and 20.96 % of the total, respectively. Furthermore, the concentrations of all PAEs were below China's soil quality risk control standards, and the non-carcinogenic risks to both adults and children were below the current threshold, indicating relatively low risks to both the human health and the environment. These findings are crucial for understanding the presence and safety evaluation of PAEs in Xinjiang Oasis farmland, and they provide important reference data for managing and controlling PAE contamination in agricultural soils.

Drip irrigation with plastic mulch is widely used to save water and improve fertilizer efficiency in arid regions in Xinjiang. However, farmers freely use irrigation water in pursuit of a high cotton yield, and the impact of different irrigation amounts on nitrous oxide (N₂O) emissions is still unclear. A field experiment was conducted in 2023 in Xinjiang, China, with drip-irrigated cotton (Gossypium hirsutum L.) to determine N₂O emissions with different irrigation intensities. The different irrigation treatments were designed as follows: irrigation was performed to maintain soil moisture at (1) an 80% field capacity (Q80); (2) 90% field capacity (Q90); and (3) 100% field capacity (Q100). The results showed that the yield of cotton decreased with the increase in irrigation intensity. A 100% field capacity is beneficial for ammonium and nitrate transformation. The N₂O emissions remained at a relatively low level during the non-irrigated fertilization period. In every irrigation and fertilization cycle, the N₂O emissions were mainly concentrated during the process from wet to dry. The peak occurred during days 1–3 of irrigation. Throughout the growth period, the cumulative N₂O emissions were 1.15, 1.48, and 2.63 kg N ha⁻¹ under the Q80, Q90, and Q100 treatments, respectively. As the irrigation intensity increased, the dominant species of soil bacteria and fungi showed substitution, while the dominant species of soil actinomycetes were not replaced. Fungi, actinomycetes, the available potassium, and the carbon to nitrogen ratio were positively correlated with nitrous oxide emissions, and the soil temperature was negatively correlated with nitrous oxide emissions. These results demonstrate that increased irrigation could increase the risk of greenhouse gas emissions when using plastic mulch with drip irrigation.

Drip irrigation under plastic mulch is widely used and leads to periodic drying–rewetting (DW) cycles in Xinjiang, Northwest China. However, the effect of different wet and dry alternation types on soil inorganic nitrogen transformation is not clear. Studying these issues not only provides reference for the formulation of fertilization and irrigation systems but is also of great significance for reducing non-point source pollution. An incubation experiment was conducted in 2018 in Baotou Lake farm in Korla City, Xinjiang, with drip-irrigated cotton (Gossypium hirsutum L.). The treatments were designed comprising three parts: (1) DW intensity (Q100, Q90, Q80, Q70, Q60); (2) DW frequency (P3d, P5d, P7d, P9d, P11d); and (3) soil wetting time (P1m, P3m, P5m). The results revealed that the contents of the NH₄⁺ and NO₃⁻ decreased with the increase in the DW intensity and were highest in the Q100 treatment. The rate of net N mineralization decreased with the increase in the DW intensity. The highest rate (7.02 mg kg⁻¹ d⁻¹) was found in the Q70 treatment in the wet to dry process and 3.03 mg kg⁻¹ d⁻¹ in the Q60 treatment in the dry to wet process, respectively. The contents of the NH₄⁺ and NO₃⁻ were higher with the higher DW frequency (P3d). The rate of net N mineralization decreased with the increase in the DW frequency and was highest in the P3d treatment in the wet to dry process and the P5d treatment in the dry to wet process, respectively. The soil wetting time was longer with the content of NH₄⁺, NO₃⁻, and N mineralization (P5m). The rate of net N mineralization was higher with the longer soil wetting time in the wet to dry process and the shorter soil wetting time from the dry to wet process. These results demonstrate that a reasonable DW intensity, DW frequency, and soil wetting time could not only effectively promote nitrogen transformation and the absorption of nitrogen but also reduce the nitrogen losses under drip irrigation.

In the present study, we conducted three treatments with different cadmium concentrations and three different soil types selected for grape cultivation to assess the accumulation and migration characteristics of Cadmium (Cd) in the soil–grape system in different years. The change in Cd fractions in soil and the transfer and accumulation of Cd in different soil–grape systems were analyzed to evaluate the health risks of pulp cadmium accumulation to grape consumers. The results showed that after the planting of the grape, the active Cd fraction increased by 1~3 times and the stable fraction decreased by 1~3 times compared to before planting grapes. It gradually began to stabilize as the cultivation period progressed. The bioaccumulation factor (BCF) of Cd in different parts of grape was ranked as: root (0.094~2.590) > stem (0.117~2.112) > leaf (0.008~0.621) > seed (0.010~0.195) > skin (0.000~0.148) > pulp (0.000~0.156). High Cd concentration inhibited the transfer of Cd from the soil and root to the aboveground part of the grape. The Cd of grape pulp has no health risks. Cd pollution significantly altered the soil microbial community, suppressing Actinobacteria while enriching Acidobacteria. The results of this study will help to clarify migration patterns between different soil–grape systems and providing effective data and theoretical support for the management of Cd pollution in vineyard soils.