施肥管理对农田黑土土壤水分动态变化的影响

东北黑土区属"雨养农业",水分是该地区农业生产中的主要限制因子。施肥管理通过影响土壤理化性质和作物生长调控土壤水分。以中国科学院海伦农田生态系统野外科学观测研究站内的水分平衡观测场为研究对象,基于10年的观测数据,分析研究区域内长期的施肥管理对土壤水分垂直变化和季节性变化的影响。研究结果表明不同的施肥管理方式显著影响了0~90 cm土层的土壤水分含量,表现为与无肥(CK)相比,化肥(NP)和有机肥+化肥(NPM)处理的0~90 cm土层土壤含水量分别减少了1.53%和3.45%。不同施肥管理方式下剖面土壤含水量的季节性变化为土壤含水量差异的最大时期出现在8月5日,表现为CK>NP>NP。根据土壤储水量的季节性变化,将作物生长季内土壤水分划分为三个时期,分别为相对稳定期(4月30日~5月30日),水分消耗期(5月30日~6月30日)和水分恢复期(6月30日~10月5日),其中NP和NPM处理土壤储水量一直处于较低水平。土壤水分被消耗的最大时期出现在6月末。

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.