Large-Scale and Long-Term Trends and Magnitudes in Irrigated and Rainfed Maize and Soybean Water Productivity: Grain Yield and Evapotranspiration Frequency, Crop Water Use Efficiency, and Production Functions
Large-Scale and Long-Term Trends and Magnitudes in Irrigated and Rainfed Maize and Soybean Water Productivity: Grain Yield and Evapotranspiration Frequency, Crop Water Use Efficiency, and Production Functions
复制标题
灌溉和雨养玉米和大豆水生产率的大规模和长期趋势和幅度：谷物产量和蒸散频率、作物水分利用效率和生产函数
DOI：
10.13031/trans.58.10784
复制
发表时间：
2015
影响因子：
1.5
通讯作者：
V. Sharma
中科院分区：
文献类型：
--
作者：
S. Irmak;V. Sharma
摘要。作物水分利用效率（CWUE）、蒸散水分利用效率（ETWUE）和作物产量生产函数的大规模量化和制图，特别是在长期和大规模的基础上，对有效评价和管理与农业生产有关的淡水资源具有重要意义。本研究的总体目标是量化和绘制县和州尺度上CWUE和ETWUE的长期（1986-2009）幅度、趋势和频率分布，并开发内布拉斯加州灌溉和雨养玉米和大豆在县、区和州尺度上的产量生产函数。从1986年到2009年，灌溉玉米、旱作玉米、灌溉大豆和旱作大豆的产量分别增加了31%、37%、29%和33%。在此期间，灌溉玉米的粮食产量每年增加166公斤公顷，旱作玉米的粮食产量每年增加84公斤公顷。灌溉和旱作大豆的年增产分别约为50和30公斤/公顷。灌溉和旱作玉米的ET c峰值分别出现在600和400 mm处，而灌溉和旱作大豆的ET c峰值分别出现在500和400 mm处。在1区（半干旱）、2区、3区和4区（半湿润），灌溉玉米的ET c平均比旱作玉米高52%、46%、35%和25%。在2区、3区和4区，大豆的灌溉ET c分别比旱作大豆高41%、29%和15%（内布拉斯加州西部最干旱的1区不种植大豆）。所有县（90个县，24年）的玉米灌溉水分利用效率平均值为1.74 kg m -3[标准差= 0.37 kg m -3]，从半湿润区4的2.07 kg m -3到半干旱区1的1.33 kg m -3不等。对于大豆，全州（78个县，24年期间）平均灌溉CWUE为0.64 kg m -3 (SD = 0.14 kg m -3)，范围为0.81 ~ 0.54 kg m -3。玉米ETWUE平均值为2.32 kg m -3 (SD = 0.52 kg m -3)，大豆平均为1.01 kg m -3 （SD = 0.55 kg m -3）。在全州平均水平上，旱作玉米和灌溉玉米产量的变化分别约有74%和3%可以单独用ET c来解释。对于旱作大豆，碳排放当量解释了产量变化的44%；然而，灌溉大豆产量与ET c之间没有很强的关系。1986 - 2009年，1区和2区玉米CWUE显著增加，分别为35%和36%，3区和4区增幅较小，分别为17%和15%，表明通过适当的灌溉、土壤和作物管理，产量较低的区域可以更有效地提高CWUE。CWUE和ETWUE的这些巨大差异表明，提高内布拉斯加州现有作物生产系统的效率有很大的潜力。本研究中提供的CWUE和ETWUE地图以及区域和全州平均产量生产函数数据可用于评估这些变量在全州范围内的差异，以便进行密切监测、评估、资源分配和管理决策。
Abstract. Large-scale quantification and mapping of crop water use efficiency (CWUE), evapotranspiration water use efficiency (ETWUE), and crop yield production functions, especially on a long-term and large-scale basis, are important to effectively evaluate and manage freshwater resources in relation to agricultural production. The overall objectives of this study were to quantify and map the long-term (1986-2009) magnitudes, trends, and frequency distributions of CWUE and ETWUE on a county and statewide scale and develop yield production functions on a county, zonal, and statewide scale for irrigated and rainfed maize and soybean in Nebraska. From 1986 to 2009, total increases of 31%, 37%, 29%, and 33% were observed for irrigated maize, rainfed maize, irrigated soybean, and rainfed soybean yields, respectively. During that period, grain yields increased annually by 166 kg ha -1 for irrigated maize and by 84 kg ha -1 for rainfed maize. The yield increases on an annual basis for irrigated and rainfed soybean were about 50 and 30 kg ha -1 , respectively. Irrigated and rainfed maize ET c peak frequency occurred at 600 and 400 mm, respectively, and irrigated and rainfed soybean ET c peaks were at 500 and 400 mm, respectively. On average, irrigated maize ET c was 52%, 46%, 35%, and 25% greater than rainfed maize ET c in zone 1 (semi-arid), zone 2, zone 3, and zone 4 (sub-humid), respectively. For soybean, irrigated ET c was 41%, 29%, and 15% higher than rainfed soybean ET c in zones 2, 3, and 4, respectively (soybean is not grown in zone 1, the driest zone in western Nebraska). Irrigated CWUE for maize for all counties (90 counties for a 24-year period) had a mean value of 1.74 kg m -3 [standard deviation (SD) = 0.37 kg m -3 ] and ranged from 2.07 kg m -3 in sub-humid zone 4 to 1.33 kg m -3 in semi-arid zone 1. For soybean, the statewide average (78 counties for a 24-year period) irrigated CWUE was 0.64 kg m -3 (SD = 0.14 kg m -3 ) and ranged from 0.81 to 0.54 kg m -3 . The ETWUE had a mean of 2.32 kg m -3 (SD = 0.52 kg m -3 ) for maize and a mean of 1.01 kg m -3 (SD = 0.55 kg m -3 ) for soybean. On a statewide average basis, about 74% and 3% of the variability in rainfed and irrigated maize yields, respectively, was explained by ET c alone. For rainfed soybean, ET c explained about 44% of the variability in yield; however, no strong relationship was observed between irrigated soybean yield and ET c . Maize CWUE showed substantial increases (from 1986 to 2009) of 35% and 36% in zones 1 and 2, and lesser increases of 17% and 15% were observed in zones 3 and 4, indicating that zones with smaller yields could increase CWUE more effectively by proper irrigation, soil, and crop management. These wide variations in CWUE and ETWUE indicate that there is a significant potential to increase the efficiency of current Nebraska crop production systems. The CWUE and ETWUE maps and the zonal and statewide average yield production function data presented in this study can be useful for evaluating the differences in these variables across the state for close monitoring, assessment, resource allocation, and management decisions.