淹水条件下渗漏强度对稻田NO_3^--N质量浓度的影响

Influence of seepage rate on NO_3^--N concentration in flooding paddy field

基于蒸渗仪淹水稻田不同渗漏强度控制试验结果,研究了稻田施肥后和各生育阶段不同渗漏强度条件下地表水及地下水中NO3--N质量浓度(ρ(NO3--N))的变化特性.结果表明:分蘖肥施用后,地表水和地下水中ρ(NO3--N)都有不同程度的升高,地表水ρ(NO3--N)短暂升高后便回落,地下水ρ(NO3--N)上升明显,5d上升了462.3%;稻田补水会扰动土壤,促进土壤表层吸附的NH4+-N的硝化进程,使地表水中ρ(NO3--N)升高,随着淹水时间的增加,ρ(NO3--N)会随之降低.水稻各生育期,不同渗漏强度对地表水中ρ(NO3--N)影响不显著,对地下水中ρ(NO3--N)的影响显著,渗漏强度大的地下水中ρ(NO3--N)升高明显.

Through the experimental tests on flooding paddy field under different seepage rates by use of lysimeter,the variation characteristics of NO-3N concentration（ρ（NO-3-N）） in surface and ground water of the paddy field were studied after fertilizer application and during various growth stages of the paddy rice.The results show that,NO-3-N concentration in surface and ground water both increase to some extent after tiller and fertilizer application,that in surface water quickly falls after a short increase,but that in ground water obviously increases,with an increase of 462.3% in 5 days.The water compensation will disturbs the soil and accelerate the variation of NH＋4-N to NO-3-N in the soil surface and result in the increase of NO-3-N concentration in the surface water.With the increase of flooding time,the NO-3-N concentration will decrease.During various growth stages of the paddy rice,the influence of different seepage rates on the NO-3-N concentration in the surface water is not obvious,but that in the ground water is obvious.The NO-3N concentration in the ground water with high seepage rate has obvious increase.