限量灌溉对京郊小麦产量、水分利用效率及效益的影响

Effect of Limited Irrigation on Wheat Yield,Water Use Efficiency and Its Planting Benefits in Beijing

为明确北京及周边地区限量灌溉下小麦适宜的灌水制度,设置5个灌水梯度,以北京平均灌溉水平2 550m3·hm-2为对照(CK),逐渐减少用水量到2 100、1 650、1 200和750m^3·hm^(-2),通过田间和盆栽试验,研究灌水对小麦生长、产量、水分利用效率及效益的影响。结果表明,与对照相比,灌水量为2 100和1 650m^3·hm^(-2)的处理下,小麦产量降幅未达显著水平,其余两个处理(1 200和750m^3·hm^(-2))的产量显著降低。减产源于有效穗数和穗粒数的减少;有效穗数的减少源于群体茎蘖数(起身、拔节)的减少,穗粒数的减少源于穗长的缩短、不孕小穗数增加和有效小穗数减少。随着灌水量的减少,小麦的水分利用效率提高,其中灌水1 650m^3·hm-2的处理水分利用效率最高。与对照相比,灌水2 100和1 650m^3·hm^(-2)的处理,每公顷效益减少290元以内,其余两个处理减少超过1 700元。综合考虑产量、效益、水分利用效率,在限制灌溉量无补贴的情况下,灌水量为1 650 m^3·hm^(-2)(越冬水750 m^3·hm^(-2)、拔节水450 m^3·hm^(-2)、灌浆水450m^3·hm^(-2))的节水灌溉模式最佳。

Four irrigation treatments（2 100 m^3·hm^-2, 1 650 m^3·hm^-2, 1 200 m^3·hm^-2 and 750 m^3· hm^-2） were set to investigate the effects of limited irrigation in Beijing on wheat growth, yield, water use efficiency and its planting benefits by field and pot experiments, with the average amount of irrigation（2 550 m^3·hm^-2） as control（CK）. The results indicated that： compared with the control, yield reduction was not significant under irrigation amount of 2 100 ma·hm^-2 and 1 650 ma·hm^-2 , while that was significant under the other two treatments（1 200 ma·hm^-2 and 750 ma·hm 2）. Yield reduction was due to the decrease of effective spikes and kernels per spike. Decreased spikes were due to the reduction of tillers（setting stage and jointing stage）. The spike length was shortened, and sterile spikelets was increased, and eventually effective spikelets was reduced, which led to the reduction of kernel number per spike. With the reduction of irrigation, water use efficiency increased and reached the maximum under the treatment of 1 650 ma·hm^-2. Compared with the control, the net output of wheat was decreased less than 290 yuan per hectare under irrigation amount of 2 100 m^3·hm^-2 and 1 650 m^3·hm^-2, and that was decreased more than 1 700 yuan under the other two treatments. Taking the yield, water use efficiency and benefits into account, under limited irrigation without subsidies, the irrigation amount of 1 650 ma·hm^-2 （winter water 750 m^3·hm^-2, jointing water 450 ma·hm^-2 and filling water 450 m^3·hm^-2） is suitable.