Dynamics of Water Contents in Arable Black Soil as Affected by Fertilization Practices

Black soil region in Northeast china belongs to rain-fed farmland with the main limitation of water in agricultural production.Soil water could be regulated by changing soil physical-chemical properties and crop growth through different fertilization practices.The vertical and temporal variations of soil water affected by long-term fertilization practices were considered on the base of decades of field observation in Hailun national field research station.The results showed that fertilization management impacted significantly soil water content in 0-90 cm depth of black soil with the decrease order of no fertilizer(CK),chemical fertilizer(NP) and chemical fertilizer + organic matter(NPM).And soil water content was separately decreased by 1.53% in NP and 3.45% in NPM,compared with CK.The maximal difference of soil water content in temporal variation under fertilization practices was observed on August 5 with an increase order of NPM,NP and CK.Three periods associated with temporal variation of soil water storage were drawn as follows: relatively stable period from April 30 to May 30,water consumption period from May 30 to June 30,water recharge period from June 30 to October 5.The soil water storage of NP and NPM was in lower overall growing season compared with CK,water storage in 0-170 cm soil depth was consumed to the greatest extent by the end of June.