Grain yield, irrigation-yield production functions (IYPFs), evapotranspiration-yield production functions (ETYPFs), total soil water-yield production function (TSWYPF), crop evapotranspiration (ET), and basal ET (ET) response of subsurface drip-irrigated (SDI) maize were investigated under full irrigation treatment (FIT), 75 % FIT, 50 % FIT, and rainfed (RF). Yield response to irrigation differed significantly (P<0.05) between the treatments with FIT having the highest grain yield, followed by 75 % FIT, 50 % FIT, and RF in all growing seasons. There was a 14, 6, and 12 % yield reduction in 75 % FIT, 50 % FIT, and RF with respect to FIT, respectively. FIT had the highest ET, followed by 75 % FIT, 50 % FIT, and RF. ET reduction with 75 % FIT, 50 % FIT and RF with respect to FIT had similar reductions between the years. Under these experimental conditions, ET of SDI-irrigated maize can be expected to be reduced by 5.2 % (25 mm), 13 % (65 mm), and 26 % (130 mm) with the limited irrigation (75 % FIT and 50 % FIT) and RF, respectively. The amount of irrigation water required for maximum grain yield varied between the growing seasons as a function of climatic conditions (262, 225, and 173 mm in 2004, 2005, and 2006, respectively). Based on the IYPFs, a 25.4 mm of irrigation application resulted in 0.061, 0.063, and 0.066 t/ha yield increase (beyond the intercept) in 2004, 2005, and 2006, respectively, with a 3-yr average of 0.063 t/ha. A 25.4 mm of irrigation application resulted in 15.6, 16.0, and 13.7 mm of increase in ET (beyond the intercept) in 2004, 2005, and 2006 seasons, respectively, with a 3-yr average of 15.1 mm. On a three-year average basis, 10.7, 29.1, and 67 % yield reduction in 75 % FIT, 50 % FIT, and RF treatments with respect to FIT can be expected under these climate, soil-water, and crop management conditions with SDI-irrigated maize. A strong dependence of the ETYPF slopes on RF treatment’s yield was observed. ET had substantial inter-annual variation as 356, 230, and 315 mm in 2004, 2005, and 2006, respectively. ET was strongly and positively correlated (R=0.99) with the seasonal precipitation and strongly, but negatively correlated (R=0.89) with seasonal cumulative thermal unit (Growing Degree Days). Based on the pooled ETYPFs, a 25.4 mm of ET resulted in 1.86, 1.72, and 2.61 t/ha grain yield (beyond the intercept) in 2004, 2005, and 2006, respectively, with a seasonal average of 2.1 t/ha. Data and information of this research can provide guidance for irrigation professionals, managers, advisors, engineers, agronomists, economists, and other professionals and can be incorporated into the planning, forecasting, allocating and managing of water resources availability-demand-actual use analyses and decisions to enhance crop production efficiency.

中文翻译：

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玉米对不同地下滴灌管理策略的响应：产量、生产函数、基础蒸散量和作物蒸散量


粮食产量、灌溉产量生产函数（IYPFs）、蒸散量-产量生产函数（ETYPFs）、土壤总水量生产函数（TSWYPF）、作物蒸散量（ET）和地下滴灌的基础蒸散量（ET）响应(SDI) 玉米在完全灌溉处理 (FIT)、75% FIT、50% FIT 和雨养处理 (RF) 下进行了调查。在所有生长季节，FIT 处理的籽粒产量最高，其次是 75% FIT、50% FIT 和 RF，对灌溉的产量反应差异显着（P<0.05）。与 FIT 相比，75% FIT、50% FIT 和 RF 的产量分别降低了 14%、6% 和 12%。 FIT 的 ET 最高，其次是 75% FIT、50% FIT 和 RF。 ET 减少 75% FIT、50% FIT 和 RF 相对于 FIT 的减少量在这些年之间也有类似的减少。在这些实验条件下，在有限灌溉（75％FIT和50％FIT）的情况下，SDI灌溉玉米的ET预计可减少5.2％（25mm）、13％（65mm）和26％（130mm）。 FIT) 和 RF 分别。粮食最高产量所需的灌溉水量因气候条件的不同而在不同生长季节有所不同（2004 年、2005 年和 2006 年分别为 262、225 和 173 毫米）。根据 IYPF，2004 年、2005 年和 2006 年，25.4 毫米的灌溉量分别导致产量增加 0.061、0.063 和 0.066 吨/公顷（超出截距），三年平均值为 0.063 吨/公顷。 2004年、2005年和2006年季节，25.4毫米的灌溉量导致ET（超出截距）分别增加15.6、16.0和13.7毫米，三年平均值为15.1毫米。三年平均为 10.7、29。如图 1 所示，在这些气候、土壤水和作物管理条件下，SDI 灌溉玉米的 75% FIT、50% FIT 和 RF 处理预计产量会减少 67%。观察到 ETYPF 斜率对 RF 处理产量的强烈依赖性。 2004年、2005年和2006年ET的年际变化较大，分别为356、230和315毫米。 ET 与季节性降水呈强正相关（R=0.99），与季节累积热量单位（生度日）呈强负相关（R=0.89）。根据汇总的 ETYPF，2004 年、2005 年和 2006 年，25.4 毫米的 ET 导致粮食产量分别为 1.86、1.72 和 2.61 吨/公顷（超出截距），季节平均产量为 2.1 吨/公顷。这项研究的数据和信息可以为灌溉专业人员、管理者、顾问、工程师、农学​​家、经济学家和其他专业人员提供指导，并可纳入水资源可用性-需求-实际使用分析和规划、预测、分配和管理。提高作物生产效率的决策。