新型灌溉模式下测墒补灌对农田水氮及小麦产量的影响

Effects of Soil Moisture Measurement and Supplemental Irrigation on Farmland Water,Nitrogen and Wheat Yield under New Irrigation Mode

【目的】研究新型灌溉模式对农田水氮及小麦产量的影响。【方法】选用鲁麦21为试验对象进行大田试验,采用二因素裂区设计,灌水量为主区,设拔节期和扬花期均测墒补灌至田间持水率的65%(W_(65))、75%(W_(75))、85%(W_(85))3个水平;灌溉方式为副区,设滴灌(D)、微喷灌(WP)和拔节期微喷灌扬花期滴灌(WP+D)共3种灌溉方式,研究灌水量和灌溉方式对土壤水氮分布、小麦产量、水分利用效率及经济效益的影响。【结果】低于田间持水率的灌溉只对0~40 cm土层产生影响,小麦全生育期内40~100 cm土层土壤含水率没有波动,即0~40 cm土层为主要的供水层及持水层,土壤含水率表现为W_(85)处理>W_(75)处理>W_(65)处理;0~60cm土层土壤硝态氮量在W_(65)、W_(75)灌水量及微喷灌模式下较高,且随着灌水量增多硝态氮淋溶风险增大;成熟期,灌水量、灌溉方式及二者交互作用对40~100 cm土层土壤硝态氮量产生了极显著影响;随着灌水量增加,产量及水分利用效率均表现出先增加后降低趋势,在拔节期微喷灌结合扬花期滴灌的模式下可以达到更好的节水保产效果,产量达到了6147.5 kg/hm^(2),水分利用效率为16.2 kg/(hm^(2)·mm),且达到了较高的经济效益8429.0元/hm^(2)。【结论】综上可知,拔节期和扬花期均测墒补灌至田间持水率的75%并配合微喷灌+滴灌的模式,可以实现小麦生产节水环保增效的目标。

【Background】In order to solve the problem of water resources waste caused by unreasonable irrigation,water-saving irrigation for wheat was studied.【Method】Lumai 21 was selected as the experimental object for field experiment.The split plot design with two factors was adopted,the irrigation amount was the main area and the soil moisture was measured at jointing stage and flowering stage to supplement irrigation to three levels of 65%(W_(65)),75%(W_(75))and 85%(W_(85))of field water capacity.The irrigation mode was the sub area with three modes:drip irrigation(D),micro sprinkler irrigation(WP)and micro sprinkler irrigation at jointing stage and drip irrigation at flowering stage(WP+D).The effects of irrigation amount and irrigation mode on soil water and nitrogen distribution,wheat yield,water use efficiency and economic benefit were studied.【Result】The results showed that the irrigation below the field capacity only affected the 0-40 cm soil layer,and the soil water content of 40-100 cm soil layer didn’t fluctuate during the whole growth period of wheat after irrigation,so 0-40 cm was the main water supply layer and water holding layer,and the soil water content was shown as W_(85)treatment>W_(75)treatment>W_(65)treatment.Nitrate nitrogen content in 0-60 cm soil layer was higher under W_(65),W_(75)irrigation amount and micro sprinkler irrigation mode,and the risk of nitrate nitrogen leaching increased with the increase of irrigation amount.At the mature stage,the irrigation amount,irrigation mode and their interaction had a significant impact on the 40~100 cm soil layer.With the increase of irrigation amount,both the yield and water use efficiency shown a trend of first increasing and then decreasing.Under the mode of micro sprinkler irrigation at jointing stage combined with drip irrigation at flowering stage,better water-saving and yield assurance can be achieved,with the yield of 6147.5 kg/hm^(2),water use efficiency of 16.2 kg/(hm^(2)·mm),and higher economic benefit of 8429.0 yuan/hm^(2).【Conclusion】In general,the goal of water saving and environmental protection for wheat production can be achieved by measuring soil moisture and supplementing irrigation to 75%of the field capacity at jointing and flowering stages and combining micro sprinkler irrigation with drip irrigation.