减氮适水对冬小麦光合特性与土壤水氮分布的影响

Effects of Nitrogen-reducing and Suitable Water on Photosynthetic Characteristics of Winter Wheat and Distribution of Soil Water and Nitrogen

针对华北平原农业生产中存在的灌溉水资源不足、氮肥投入过量的问题,以冬小麦为材料,分别设置3个供水水平(W1(60%ETc(参考作物需水量),300 mm)、W2(75%ETc,370 mm)、W3(ETc,495 mm))和3个施氮水平(N1(180 kg/hm^(2))、N2(255 kg/hm^(2))、N3(330 kg/hm^(2))),于2018—2019年利用渗漏池小区进行田间试验,研究不同水氮对土壤水氮分布、冬小麦旗叶功能期内光合特性、光响应曲线参数以及籽粒产量的影响。结果表明:减氮适水(W2N2)能在维持冬小麦生长需求的前提下,提高水氮利用效率,较W3N3处理多利用土壤蓄水量41.12 mm,减少硝态氮淋失量15.87%;水氮协同对小麦旗叶光合特性影响显著,W2、W3处理的旗叶光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)明显高于W1处理,但二者差异不显著,N2、N3处理的旗叶Pn、Tr和Gs明显高于N1处理,且二者差异也不显著;测产结果显示,W2N2产量最高,且差异显著,产量与光合特性、部分光响应曲线参数呈显著性关系,这说明水氮对光合特性的提高有利于光合产物的积累,进而提高了产量。在本试验条件下,冬小麦生育期供水量370 mm、施氮肥255 kg/hm^(2)时,既能维持冬小麦较高的光合特性和产量,又能提高土壤蓄水的利用和降低硝态氮淋失风险,达到华北平原冬小麦生产节水、减肥、环保、增效的目的。

Insufficient irrigation water resources and excessive input of nitrogen fertilizer are very common in agricultural production in North China Plain.In order to deal with these problems,a field trial with winter wheat as test material was conducted in the lysimeters in 2018—2019.Under three irrigation levels of W1(60%ETc(reference crop water requirement),300 mm),W2(75%ETc,370 mm)and W3(ETc,495 mm),and three nitrogen levels of N1(180 kg/hm^(2)),N2(255 kg/hm^(2))and N3(330 kg/hm^(2)),the effects of irrigation-fertilization methods on soil water and nitrogen distribution,photosynthetic characteristics and light response curve parameters of winter wheat flag leaf function period and wheat grain yield were examined.The results showed that W2N2 treatment can maintain wheat growth demand and improve water and nitrogen use efficiency,which increased soil water storage by 41.12 mm and decreased soil nitrate leaching by 15.87%,compared with that of W3N3 treatment.The interaction of water and nitrogen had a significant effect on the photosynthetic characteristics of wheat flag leaves.The Pn,Tr and Gs of W2 and W3 treatments was significantly higher than that of W1 treatment,but there was no significant difference between them,and N treatment had the same response.According to the result of yield test,W2N2 had the largest yield,with significant difference than other treatments.In addition,there was a significant relationship between yield and photosynthetic characteristics,light response curve parameters,which indicated that the improvement of photosynthetic characteristics caused by water and nitrogen was conducive to the accumulation of photosynthetic products,and then increased the yield.Under the conditions of this experiment,W2 treatment(irrigated 370 mm in overwintering period,75%ETc)combined with N2 treatment(with nitrogen application rate of 255 kg/hm^(2))can not only maintain high photosynthetic characteristics and crop yield,but also improve the utilization of soil water storage and reduce the risk of nitrate leaching,realizing the water-saving and nitrogen reduction production of winter wheat in the North China Plain.