School of Geographic Sciences and Tourism, Jiaying University, Guangdong, China.
Paotai Soil Improvement Experimental Station, Shihezi, XinJiang, China.
PLoS One. 2020 Dec 30;15(12):e0244404. doi: 10.1371/journal.pone.0244404. eCollection 2020.
The drip irrigation under mulch has become one of significant supporting technologies for cotton industry development in Xinjiang, and has shown the good economic and ecological benefits. With the rapid development of society and economy in Southern Xinjiang, the conventional mode of large-quota winter and spring irrigation, salt leaching and alkali decreasing is difficult to support sustainable development of land and water resources in Southern Xinjiang. This study tries to adjust soil moisture and salt content regulation mode of massive water salt leaching and drip irrigation under mulch in the non-growing period of cotton field in Southern Xinjiang, explores interannual soil salinity change features of drip irrigation cotton field without winter and spring irrigation, and provides experimental basis for drip irrigation technology under mulch which can reduce and exempt cotton irrigation in winter and spring. According to ET0, the dual-factor complete combination experiment involving 3 irrigating water quotas (I1, I2, I3) and 2 irrigation times (T12, T16) was designed, and 6 treatments were involved in total(I1T12,I2T12,I3T12,I1T16,I2T16 and I3T16). The investigation results of four-year (2012-2015) field positioning experiment showed that, under the condition of "germination under drip irrigation" without winter and spring irrigation, increasing irrigation quota and irrigation times could lower 0-100cm soil salinity accumulation, but the soil salinity accumulation degree was 40-100cm, and less than 0-30cm. In the seedling stage, bud stage, blossom and boll-forming stage, and boll opening stage, the average salinity of 0-100cm soil increased by 39.81%, 31.91%, 26.85% and 29.47%, respectively. Increasing irrigation quota and irrigation times could ease interannual soil salinity accumulation degree of cotton field with drip irrigation under mulch, without winter and spring irrigation. 0-100cm soil salinity before sowing was related to the irrigation quota of cotton in the growing stage of the last year. The larger the irrigation quota was, the smaller the soil salinity before sowing would be. The accumulation amount of soil salinity at the end of growing stage under different treatments was lower than that before sowing. The drip irrigation of cotton under mulch in the growing stage could effectively regulate soil salinity distribution and space-time migration process in the growing stage of cotton. Compared with the beginning of 2012, 0-100cm average soil salinity under 3 irrigation quotas (I1, I2, I3) was 33.66%, 5.60% and 1.24%, respectively. Salt accumulating rates under 12 irrigations and 16 irrigations were 20.66% and 6.33%, respectively. The soil had the risk of salinization when the "germination under drip irrigation" without winter and spring irrigation was used. Such results can provide the reference for prevention and treatment of soil moisture and salt content of cotton field with drip irrigation under mulch in the arid region.
膜下滴灌已成为新疆棉花产业发展的重要支撑技术之一，具有良好的经济和生态效益。随着南疆社会经济的快速发展，传统的冬春大定额灌溉、洗盐降碱模式已难以支撑南疆水土资源的可持续发展。本研究尝试调整南疆棉田非生长季大量水盐洗灌和膜下滴灌的土壤水分和盐分调控模式，探索无冬春灌滴灌棉花田的土壤盐分年际变化特征，为冬季和春季免滴灌节水提供试验依据。根据 ET0，设计了涉及 3 个灌水量（I1、I2、I3）和 2 个灌溉次数（T12、T16）的双因素完全组合试验，共涉及 6 个处理（I1T12、I2T12、I3T12、I1T16、I2T16 和 I3T16）。四年（2012-2015 年）田间定位试验调查结果表明，在不进行冬春灌的“滴灌下播种”条件下，增加灌水量和灌溉次数可以降低 0-100cm 土壤盐分积累，但土壤盐分积累程度在 40-100cm 处，小于 0-30cm 处。在苗期、蕾期、开花结铃期和吐絮期，0-100cm 土壤平均盐分分别增加 39.81%、31.91%、26.85%和 29.47%。增加灌水量和灌溉次数可以缓解南疆无冬春灌膜下滴灌棉田的土壤盐分年际积累程度。播种前 0-100cm 土壤盐分与上一年棉花生长阶段的灌水量有关，灌水量越大，播种前土壤盐分越小。不同处理结束时生长阶段土壤盐分的积累量低于播种前。棉花生长阶段的膜下滴灌可以有效调节棉花生长阶段土壤盐分的分布和时空迁移过程。与 2012 年初相比，3 个灌水量（I1、I2、I3）下 0-100cm 平均土壤盐分分别为 33.66%、5.60%和 1.24%，12 次和 16 次灌溉的盐积累率分别为 20.66%和 6.33%。在不进行冬春灌的“滴灌下播种”条件下，土壤有盐渍化风险。这些结果可为干旱地区膜下滴灌棉田土壤水分和盐分的防治提供参考。
