The arid and semi-arid regions of northwest China play a pivotal role in the national cotton production. However, soil salinization poses a severe constraint on seed cotton yield in this region. Salt leaching by drip irrigation has become increasingly popular for ameliorating saline-alkali soils. Yet, the most effective approach for utilizing drip irrigation leaching to maximize cotton productivity remains uncertain. Over a three-year period, field experiments were performed to explore the effects of four leaching amounts (75, 150, 225, and 300 mm) and four leaching times (seedling stage, budding stage, flowering stage, and boll-setting stage as one, two, three and four times) on soil-water dynamics, ion composition, source-sink relationships, seed cotton yield and its stability in saline-alkali cotton fields under drip irrigation. The study revealed that soil moisture significantly fluctuated during the cotton growing seasons. Timely irrigation significantly boosted soil moisture content by 11.3 %-23.5 %. Soil salinity was lower at the early growth stages of cotton, but it gradually increased over time, peaking at the flowering and boll-setting stages. Appropriate leaching effectively mitigated soil salinity, particularly at the flowering stage, resulting in a reduction of salt accumulation by 13.9 %-32.7 %. As leaching amount increased, the relative content of Ca increased, while K and Na contents gradually decreased, thereby reducing the relative content of harmful ions and leading to a decrease in SAR by 7.07 %-34.3 %. In terms of biomass, the W3 treatment exhibited the highest level, whih was 1.68 %-25.4 % greater than that of the other treatments. Among the three years, the S3 and S4 treatments consistently produced the highest biomass, with increases of 12.66 %-35.25 % and a slight 0.85 % difference, respectively. The optimal leaching strategy, combining the W3 irrigation amount with the S3 leaching times achieved the highest seed cotton yield with the lowest yield variability. This underscored the critical importance of suitable irrigation and management practices for enhancing seed cotton yield and mitigating the adverse effects of soil salinity on cotton production. Soil salinity indicators, such as sodium adsorption ratio and exchangeable sodium percentage, played a pivotal role in biomass accumulation and yield stability. A total leaching amount of 300 mm applied at the seedling, budding, flowering, and boll-setting stages was recommended to maximize cotton productivity.

中文翻译：

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最佳滴灌淋洗量和淋洗次数通过改善土壤化学环境和源库关系提高籽棉产量及其稳定性


西北干旱半干旱地区在全国棉花生产中占有举足轻重的地位。然而，土壤盐碱化严重制约了该地区籽棉产量。通过滴灌浸盐来改善盐碱土壤已变得越来越流行。然而，利用滴灌浸出来最大限度地提高棉花生产力的最有效方法仍然不确定。通过田间试验，历时3年，探讨了4种淋水量（75、150、225、300 mm）和4种淋水时间（苗期、现蕾期、开花期、结铃期）的影响。 1、2、3、4次）对滴灌盐碱棉田的土壤-水动态、离子组成、源库关系、籽棉产量及其稳定性进行了研究。研究表明，棉花生长季节土壤湿度波动显着。及时灌溉使土壤含水量显着提高11.3%-23.5%。棉花生长初期土壤盐分较低，但随着时间的推移，土壤盐分逐渐增加，在花铃期达到峰值。适当的淋洗有效缓解了土壤盐分，特别是在开花期，盐分积累减少了13.9%-32.7%。随着浸出量的增加，Ca的相对含量增加，而K和Na的含量逐渐下降，从而降低了有害离子的相对含量，导致比吸收率下降了7.07%-34.3%。就生物量而言，W3处理的水平最高，比其他处理高1.68%-25.4%。三年中，S3和S4处理始终产生最高的生物量，增加了12。分别有 66%-35.25% 和 0.85% 的轻微差异。最佳浸出策略，结合W3灌溉量和S3浸出次数，实现了最高的籽棉产量和最低的产量变异性。这强调了适当的灌溉和管理措施对于提高籽棉产量和减轻土壤盐分对棉花生产的不利影响至关重要。土壤盐分指标，如钠吸附率和交换性钠百分比，对生物量积累和产量稳定起着关键作用。建议在苗期、现蕾期、开花期和结铃期施用总浸出量为 300 毫米，以最大限度地提高棉花生产力。