基于CROPWAT模型的玉米需水量及灌溉制度研究

Water Requirement and Irrigation Schedule of Maize Based on the CROPWAT Model

【目的】研究黑龙江西部气候变化对玉米需水量影响及不同降雨年型下喷灌、膜下滴灌的灌溉制度。【方法】基于黑龙江省肇州县1988—2015年气象资料、作物参数和土壤数据,利用Mann-Kendall趋势检验法分析了玉米生育期内各气象因素变化规律,结合CROPWAT模型研究了黑龙江省西部玉米需水量、有效降雨量和灌溉需水量的年际和各生育期间的变化规律并总结归纳了导致这些变化的气象原因,分析了不同降雨年型作物需水量与有效降雨量的耦合度并制订了相应的喷灌和膜下滴灌灌溉制度。【结果】(1)玉米生长期内,月平均最高温度和月平均最低温度显著升高,月平均风速显著降低;(2)玉米生长期内需水量受最高温度影响,以8.72 mm/10 a的速率增长,变化范围为374.7~537.0 mm;(3)特枯水年、枯水年、平水年和丰水年的需水量分别为500.3、470.8、442.8、395.4 mm。(4)不同降雨年型作物需水量与有效降雨量的耦合度总体呈先升增大后减小的变化趋势;(5)喷灌条件下,特枯水年、枯水年和平水年的灌溉净定额分别为187.4、125.4、49.2 mm;(6)膜下滴灌条件下,特枯水年、枯水年和平水年的灌溉净定额分别为163、95.6、35.8 mm。【结论】在气候变化背景下,该地区有效降雨呈减小趋势,玉米需水量呈增大趋势,除丰水年外,有效降雨量难以满足玉米的需水要求,在农业生产中应根据不同降雨年型在抽雄期和灌浆期进行适量灌溉来保证玉米稳产、高产。

【Objective】The primary objective of this paper is to analyze the effects of climate change on water requirement of maize under sprinkle and mulched drip irrigations as well as their associated irrigation schedules under different annual rainfalls in Western Heilongjiang Province.【Method】Using available data from 1988-2015, the CROPWAT model and the Mann-Kendall trend test method, we first estimated the temporal change in meteorological factors, water consumption of the maize, effective rainfall, water requirement for irrigation, as well as their relationships in Zhaozhou County of Western Heilongjiang Province. We then analyzed the relationship between the effective rainfall and water requirement of the maize, and calculated the associated irrigation schedule for both sprinkler irrigation and mulched drip irrigation under different annual rainfalls.【Result】（1）During growing season of the maize, the monthly-average maximum and minimum temperatures both increased steadily while the wind speed decreased.（2）The water requirement of the maize was in the range of 374.7-537.0 mm, positively related to the highest temperature and increasing at 0.872 mm per autumn.（3） In extremely dry year, slight dry year, moderate dry year and wet year, the demands of maize for water was 500.3, 470.8, 442.8 and395.4 mm, respectively.（4）The correlation coefficients between water requirement of the maize and the effective rainfall varied, increasing first and then decreasing.（5） The amount of sprinkler irrigation in extremely dry year,dry year and moderate dry year was 187.4 mm, 125.4 mm and 49.2 mm, respectively.（6）The amounts of mulched drip irrigation in extremely dry, dry and moderate dry year was 163 mm, 95.6 mm and 35.8 mm, respectively.【Conclusion】Under climate change, the effective rainfall decreases while the water requirement of maize increases. The effective rainfall is hence unable to meet the demand of the maize for water except in wet years. Appropriate irrigations at tassel and filling stages is essential to sustain maize production.