水肥耦合条件下保护地土壤硝态氮动态变化

Dynamic Changes of Soil NO_3^-—N under the Coupling of Irrigation and Fertilization in Protected Field

采用二因素三水平完全设计,通过保护地低压节点渗灌番茄小区栽培试验,研究了灌溉上限和施肥量组合处理在灌溉追肥后第1、2、35、、7 d不同土层土壤硝态氮的动态变化。结果表明,较低灌溉上限,施肥量对不同时间土壤硝态氮影响不明显;提高灌溉上限,施肥量增加影响土壤剖面分异。灌溉上限和肥料对土壤硝态氮累积量的影响除第一天外均达到5%显著水平,作用由大到小分别为肥料,水分,水肥交互作用。不同采样时间0～20 cm土层硝态氮累积百分比平均在50%以上,低灌溉上限和高施肥量组合的硝态氮累积百分比最大,高灌溉上限和高施肥量组合硝态氮累积百分比最小。

A plot experiment of low pressure of node subsurface irrigation was conducted by means of 2-factor 3-level full combination experiment design in protected field.And the soil nitrate nitrogen dynamic changes of different soil layers was studied under the combination research of irrigation upper limit and fertilization amount at the time of 1,2,3,5,7 days after fertigation topdressing.The results showed that irrigation upper limit and fertilization amount could affect the accumulation in surface and the profile dynamic changes of soil nitrate nitrogen with different times after fertigation topdressing in tomatoes protected cultivation.The effect of fertilizer amount on the soil nitrate content was not obvious at different sampling time under the lower irrigation upper limit,and the increase of fertilization amount could affect the profile differentiation of soil nitrate content by the increasing of the irrigation upper limit.The effects of irrigation upper limit and fertilization amount on soil nitrate accumulation were significant at 5% level except the 1st day,and the order of their efficiencies decreased as fertilization amount,irrigation upper limit and the interaction of the irrigation upper limit and fertilization amount.Soil nitrate nitrogen accumulation increased with the increasing of irrigation upper limit or fertilization amount.At the different sampling times,average soil nitrate cumulative percentage of 0-20 cm soil layer occupied more than 50%,and curved surface of response showed that soil nitrate cumulative percentage was maximum under the combination of low irrigation upper limit and high fertilization amount,while soil nitrate cumulative percentage was minimum by the combination of high irrigation upper limit and high fertilization amount.