灌水量与施氮量对不同类型土壤中硝酸盐运移的影响

Effects of Irrigation and Nitrogen Application on Nitrate Transport in Different Soils

为研究一维条件下灌水量与硝酸盐淋溶损失的关系,采集宁夏日光温室条件下两种类型的土壤(灌淤土、灰钙土)做成1 m土柱,设置两个灌水量(T1:2.25×103 t/hm^2、T2:4.50×103 t/hm^2)和两个施氮量(N1:450 kg/hm^2、N2:675 kg/hm^2),测定不同处理后土壤剖面水分和硝态氮含量、计算表层累积量及深层淋溶量,并测定不同处理淋溶液硝态氮浓度及其他化学性质。结果表明:①不同土壤类型和施氮量对土壤剖面质量含水量有显著影响。②灌淤土硝态氮含量高于灰钙土;T2处理各层土壤硝态氮含量低于T1处理。4个处理相比,硝态氮的峰值均出现在60~80 cm处,土壤硝态氮含量表层、深层T2N1处理均最低而T1N2处理最高。③T1、T2处理硝态氮累积量相比,T2较T1表层累积量减少33.5,深层减少17.14;N1、N2处理相比,N2较N1表层累积增加48.72,深层增加28.8。④土壤类型、灌水、施肥对淋溶液中硝态氮及其他化学性质均有显著影响。由此可见,土壤类型、灌水量及施氮量均对土壤中氮素的累积及损失有显著影响,相比之下影响程度为施氮量>灌水量>土壤类型。

In order to study the relationship between irrigation and nitrate leaching loss under one-dimensional condition,in this study,two irrigation levels(2.25×103 t/hm^2 and 4.50×103 t/hm^2)and two nitrogen fertilizer levels(450 and 675 kg/hm^2)were set up to monitor the changes of soil water and nitrate nitrogen content and accumulation in irrigation silt and lime-calcareous soil,and the leaching solution properties under different treatments were determined.The results showed that:①different soil types and nitrogen application rates had significant influence on the mass water content of soil profile.②the nitrate nitrogen content of irrigated soil was higher than that of gray calcareous soil.The nitrate nitrogen content of the soil in each layer treated by T2 was lower than that treated by T1.Compared with the four treatments,the peak value of nitrate nitrogen appeared at 60~80 cm,and the T2N1 treatment of soil nitrate nitrogen content was the lowest while T1N2 treatment was the highest.③Compared with the accumulation of nitrate nitrogen in T1 and T2 treatment,the surface accumulation in T2 decreased by 33.5%and the deep layer decreased by 17.14%.Compared with the treatment of N1 and N2,the accumulation of N2 increased by 48.72%in the surface layer and 28.8%in the deep layer.④soil type,irrigation and fertilization had significant effects on nitrate nitrogen and other chemical properties in the leaching solution.Therefore,it can be seen that soil type,irrigation amount and nitrogen application amount all have significant influence on the accumulation and loss of nitrogen in the soil.The order from high to low of the effect degree is nitrogen application amount,irrigation amount and soil type.