Effect of Applying Sewage Effluent with Subsurface Drip Irrigation on Soil Enzyme Activities during the Maize Growing Season

Abstract

AbstractSubsurface drip irrigation is an appropriate method when using sewage effluent for crop irrigation, but its resultant heterogeneous distribution of water and nutrients in the soil may affect enzyme activities (EAs). Field experiments were designed, with three lateral depths at 0, 15, and 30 cm beneath the soil surface and three irrigation levels of 70, 100, and 130% of evapotranspiration, to investigate the effects of lateral depth, irrigation level, and water quality on the EAs of alkaline phosphatase, urease, and invertase in soil. Over 2 years, a greater lateral depth noticeably enhanced EAs in deeper soils, while EAs at a shallow lateral depth were higher in topsoil. Compared to lateral depth, the effects of irrigation level on EAs were unstable in both years. The correlations between urease activities and NO3‐N content indicated that the character of urease activities in soil N cycling was initially facilitating N mineralization and was subsequently converted to facilitate N uptake and immobilization during the maize growing seasons. Additionally, the EAs with both sewage effluent and groundwater irrigation at harvest, were generally higher than EAs measured prior to sowing. Furthermore, the sewage effluent irrigation imposed no negative effects on nutrient exchange and ecosystem functions in the soil. Our study recommends subsurface drip irrigation as a promising method for applying sewage effluent. Copyright © 2017 John Wiley & Sons, Ltd.