Two major irrigation challenges of cotton producers in the Texas High Plains (THP) include the depletion of the Ogallala Aquifer and the highly evaporative, semi-arid environment during late spring and early summer. A recent cotton experiment using center pivot irrigation at deficit irrigation capacities showed the reduction in seasonal irrigation by 20% with minor yield loss by reducing irrigations during the vegetative period instead of attempting to store soil water during this period of high evaporative losses. Due to its method of delivery, subsurface drip irrigation (SDI) should reduce evaporation losses during the preplant and early-season periods and improve water storage efficiency and crop yield even at low irrigation capacity. Two experiments having different SDI installation designs and irrigation capacities were conducted in adjacent fields on clay loam soils over 4- and 5-year periods. Treatments included levels of preplant (PP) and vegetative (Veg) period irrigations. In both experiments, under seasonal growing conditions ranging from favorable to unfavorable, yields and crop values were only modestly increased by additional PP irrigations above that required for germination. Among treatments with common PP amounts, larger irrigation amounts during the vegetative period did not significantly (p < 0.05) increase yield or crop value in any individual year or any group of years. In three growing season groupings, with unfavorable to favorable weather conditions, as seasonal irrigation increased, gross irrigation value decreased. Results suggest that in most years, on heavy soils within the THP, SDI productivity can be improved by limiting PP and early-season irrigations under deficit irrigation conditions.

中文翻译：

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在德克萨斯高平原使用地下滴灌 (SDI) 系统进行种植前和早季棉花灌溉时间的不足

德克萨斯高原 (THP) 棉花生产商面临的两大灌溉挑战包括奥加拉拉含水层的枯竭和春末夏初的高度蒸发、半干旱环境。最近一项在灌溉能力不足的情况下使用中心枢轴灌溉的棉花试验表明，通过在营养期减少灌溉而不是在蒸发损失高的时期试图储存土壤水，季节性灌溉减少了 20%，但产量损失较小。由于其输送方式，地下滴灌 (SDI) 应减少种植前和早季期间的蒸发损失，并提高蓄水效率和作物产量，即使在灌溉能力较低的情况下也是如此。在 4 年和 5 年的时间里，在黏壤土的相邻田地中进行了两个具有不同 SDI 安装设计和灌溉能力的实验。处理包括种植前 (PP) 和营养 (Veg) 期灌溉水平。在这两个实验中，在从有利到不利的季节性生长条件下，产量和作物价值仅通过高于发芽所需的额外 PP 灌溉而适度增加。在使用普通 PP 量的处理中，营养期较大的灌溉量不会显着（p < 0.05）增加任何单独年份或任何年份组的产量或作物价值。在三个生长季节分组中，在不利的有利天气条件下，随着季节性灌溉的增加，灌溉总价值下降。结果表明，在大多数年份，