Li Nan-Nan, Li Jun-Hong, Shi Xiao-Juan, Shi Feng, Tian Yu, Wang Jun, Hao Xian-Zhe, Luo Hong-Hai, Wang Zhan-Biao
Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, Xinjiang, China.
Institute of Western Agriculture, The Chinese Academy of Agricultural Sciences, Changji, China.
Front Plant Sci. 2024 Jul 25;15:1433719. doi: 10.3389/fpls.2024.1433719. eCollection 2024.
Planting without mulching can eliminate the residual film pollution caused by the long-term use of plastic film covers, but it will increase soil moisture evaporation and heat loss and severely reduce water use efficiency and cotton productivity in cotton ( L.) fields in arid regions. It is unclear whether the advantages of subsurface drip irrigation and nighttime irrigation can be leveraged to reduce the amount of irrigation applied in fields, improve the soil and leaf hydrothermal environments, and increase the synchronicity of yield and water use efficiency (WUE).
Therefore, in a two-year field experiment (2019-2020), cotton was grown under different irrigation treatments (I5, 3753 m ha; I4, 3477 m ha; I3, 3201 m ha; I2, 2925 m ha; and I1, 2649 m ha). The soil volumetric moisture content, soil temperature, leaf relative water content (RWC), daily changes in gas exchange parameters, lint yield, and WUE were evaluated.
The results showed that reducing irrigation can reduce the soil volumetric moisture content (0-40 cm soil layer), increase the soil temperature and soil temperature conductivity, and increase the leaf temperature, intercellular carbon dioxide concentration (Ci), and WUE; however, reducing irrigation is not conducive to increasing the leaf RWC, net photosynthetic rate (Pn), stomatal conductance (Gs), or transpiration rate (Tr). There was no significant difference in WUE between the I3 and I4 treatments from 8:00 to 20:00, but the lint yield in these treatments increased by 2.8-12.2% compared to that in the I5 treatment, with no significant difference between the I3 and I4 treatments. In addition, a related analysis revealed that the positive effects of the leaf hydrothermal environment on the Pn and soil temperature on the WUE occurs during the same period (10:00-16:00). Overall, an irrigation amount of 3201-3477 m ha applied with a subsurface nighttime irrigation system without mulching can enhance the soil moisture content and soil temperature, maintain a high photosynthetic capacity, and increase the lint yield and WUE. These results revealed that the negative impacts of plastic film contamination in arid areas can be alleviated.
不覆盖地膜种植可以消除长期使用塑料薄膜覆盖造成的残膜污染，但会增加土壤水分蒸发和热量损失，严重降低干旱地区棉田的水分利用效率和棉花产量。目前尚不清楚地下滴灌和夜间灌溉的优势是否能够用于减少田间灌溉量、改善土壤和叶片的水热环境，以及提高产量与水分利用效率（WUE）的同步性。
因此，在一项为期两年（2019 - 2020年）的田间试验中，棉花在不同灌溉处理（I5，3753立方米/公顷；I4，3477立方米/公顷；I3，3201立方米/公顷；I2，2925立方米/公顷；I1，2649立方米/公顷）下种植。对土壤体积含水量（容积含水量）、土壤温度、叶片相对含水量（RWC）、气体交换参数的日变化、皮棉产量和水分利用效率进行了评估。
结果表明，减少灌溉量会降低土壤体积含水量（0 - 40厘米土层），提高土壤温度和土壤热导率，同时提高叶片温度、胞间二氧化碳浓度（Ci）和水分利用效率；然而，减少灌溉不利于提高叶片相对含水量、净光合速率（Pn）、气孔导度（Gs）或蒸腾速率（Tr）。在8:00至20:00期间，I3和I4处理的水分利用效率没有显著差异，但与I5处理相比，这些处理的皮棉产量提高了2.8 - 12.2%，I3和I4处理之间没有显著差异。此外，相关分析表明，叶片水热环境对净光合速率的积极影响以及土壤温度对水分利用效率的积极影响发生在同一时期（10:00 - 16:00）。总体而言，采用地下夜间灌溉系统且不覆盖地膜，灌溉量为3201 - 3477立方米/公顷，可以提高土壤含水量和土壤温度，保持较高的光合能力，并提高皮棉产量和水分利用效率。这些结果表明，干旱地区地膜污染的负面影响可以得到缓解。
