再生水灌溉下水稻需水规律及灌溉制度试验研究

Study on the Rice Water Requirement Law and Irrigation Regime Under Reclaimed Water Irrigation

为探究再生水灌溉下水稻需水规律及再生水灌溉制度,于2019年在国家农业环境大理观测实验站开展稻田小区试验研究。试验设淹水灌溉(Flooding Irrigation, FI)及间歇灌溉(Alternate Wetting and Drying, AWD) 2种灌溉模式,以及F1 (全生育期清水灌溉+施全部化肥)、F2 (分蘖期、拔节孕穗期再生水灌溉+施部分化肥)、F3(返青期、分蘖期、拔节孕穗期再生水灌溉+施部分化肥) 3种施肥模式,共5个处理(FIF1、FIF2、FIF3、AWDF1、AWDF2)。分析不同处理下水稻需水量(ET_(c))、作物系数(K_(c))、产量及灌溉水利用效率变化,并以1970-2014年气象资料为依据探索不同水文年份的灌溉制度。结果表明,再生水灌溉会整体提高水稻各生育期ET_(c),AWD下的ET;比FI平均减少18.8 mm,差异较小。F2处理再生水灌溉量为573 mm,对再生水的利用效率最高。水稻生长初期不适宜进行再生水灌溉,再生水灌溉下水稻各生育期K;与ET;变化趋势相同。再生水灌溉水稻需水量总体表现为先增后减的趋势,拔节孕穗期达最大,高达198.6 mm,且与清水灌溉相比,峰值出现的时期后移至拔节孕穗期。在推求的不同水文年再生水灌溉制度中,AWD模式普遍具有良好的节约清水资源效果。再生水替代清水进行灌溉比率可高达75%,其中AWD比FI模式节水45.6%。再生水灌溉能够一定程度的增产,其中F2处理平均较F1增产3%。

In order to explore the law of rice water requirement under reclaimed water irrigation and the reclaimed water irrigation schedule,paddy field experiments were carried out at the National Agricultural Environment Dali Observation and Experimental Station in 2019. The experiment had five treatments(FIF1, FIF2, FIF3, AWDF1, AWDF2), and two irrigation modes of flooding irrigation(FI) and alternate wetting and drying(AWD) and three fertilization regimes of F1(fresh water irrigation during the growth period + all chemical fertilizer), F2(irrigation with reclaimed water at the tillering stage, jointing and booting stage + partial fertilizer application) and F3(irrigation with reclaimed water at the returning green stage, tillering stage, and jointing and booting stage + partial fertilizer application) were set up. Rice water requirement(ET_(c)), crop coefficient(K_(c)), yield, irrigation water use efficiency indicators and their changes under different treatments were observed, and the irrigation regimes of different hydrological years were derived based on the meteorological data for 45 years from 1970 to 2014. The results showed that, reclaimed water irrigation increased ET_(c)at all rice fertility stages as a whole, and ET;under AWD decreased by 18.8 mm on average compared with FI, which was a small difference. 573 mm of reclaimed water was irrigated in the F2 treatment, which was the most efficient use of reclaimed water. Rice was not suitable for reclaimed water irrigation at the early growth stage, and the trends of K;and ET;were the same in all rice fertility stages under reclaimed water irrigation. The water requirement of rice under reclaimed water irrigation showed a general trend of increasing and then decreasing, with the maximum at 198.6 mm at the stage of nodulation and gestation, and the peak period was shifted to the stage of nodulation and gestation compared with that of clear water irrigation. The AWD model generally had a good effect of saving clear water resources in different hydrological years of irrigation systems. The rate of replacing clear water with reclaimed water for irrigation could be as high as 75%, with AWD saving 45.6% of water compared to FI model. Irrigation with reclaimed water could increase yield to some extent, with F2 treatment increasing yield by 3% on average compared to F1.