Shenghai Pu

Cotton production under drip irrigation is common in arid and semi-arid Northwest China. Drip line placement determines the location of fertilizer application; therefore, evaluating the appropriate drip line layout and N application rate is essential for maintaining yield and reducing N losses. A two-year field experiment (2024–2025) was conducted at a single site with three independent replicates per treatment in a randomized complete block design arranged as a 2 × 2 factorial: two drip line layouts (wide-row and narrow-row) crossed with two N rates (300 and 240 kg N ha⁻¹; W300, W240, N300, and N240). Under the wide-row layout, root length density was higher (p < 0.05), and soil NO₃⁻-N was mainly distributed in the 0–60 cm layer during one fertigation cycle and across the fertilization period, overlapping with the root distribution. W240 significantly reduced NO₃⁻-N leaching and residual soil NO₃⁻-N (p < 0.05) and increased root length density and nitrogen partial factor productivity (PFPN) (p < 0.05), without reducing boll biomass, total N uptake, or seed cotton yield (p > 0.05). Under the narrow-row layout, soil NO₃⁻-N migrated rapidly downward and accumulated in the 60–100 cm layer; N240 reduced NO₃⁻-N leaching and residual soil NO₃⁻-N (p < 0.05) but also reduced cotton N uptake and seed cotton yield (p < 0.05), whereas N300 increased residual soil NO₃⁻-N and leaching and reduced PFPN (p < 0.05). Overall, under the soil, climate, cultivar, and irrigation conditions of this two-year single-site experiment, the wide-row layout with 240 kg N ha⁻¹ maintained seed cotton yield while reducing the measured NO₃⁻-N leaching and residual soil NO₃⁻-N.

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.

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.