不同有机肥对日光温室土壤剖面硝态氮含量动态变化的影响

采用田间小区试验，研究了不同有机肥对日光温室土壤硝态氮累积、分布及季节性变化的影响。结果表明，有机肥对设施土壤硝态氮的影响不同季节呈现不同特点，夏季高量有机肥的施用会引起硝酸盐在土壤、蔬菜中的累积，并加剧了硝酸氮向土壤深层的迁移；而冬季却相反，高量有机肥能够降低土壤及蔬菜中硝酸盐的含量，减少硝酸氮向土壤深层迁移。以猪粪用量（干基）22.5 t/hm2的处理为例，在夏季（番茄季），硝态氮在土壤表层(010 cm)、080 cm土层和蔬菜中的累积量分别比化肥处理高出56.69%、31.48%和23.94%；而在冬季（芹菜季），比化肥处理降低了67.38%、61.74%和6.26%。3种有机肥与化肥相比，引起土壤硝态氮周年变化幅度大小顺序为鸡粪猪粪商品有机肥化肥。因此，有机肥的施用要依据季节性的不同而有所差异，设施土壤对于春季施肥夏季收获的蔬菜，有机肥用量不宜过高，而秋季施肥冬季收获的蔬菜，有机肥用量可适当增加。

Effects of organic manures on dynamic changes of nitrate contents of soil profile in greenhouse

A field plot experiment was conducted to study the effects of different organic manures on greenhouse soil NO-3-N accumulation,distribution and seasonal changes.The results show that the impacts on greenhouse soil NO-3-N are varied with seasons under the application of the organic manures.In summer,high levels of the organic manure applications lead to NO-3-N accumulation in soil and vegetables,and promote the NO-3-N migration to the lower soil depths.On the contrary,high levels of organic manures reduce the NO-3-N contents of soil and vegetables,and reduce NO-3-N migration to the subsoil in winter.Take the treatment of swine manure with 22.5 t/ha as an example,in 0-10 cm,0-80 cm soil depth and tomato,the accumulation of NO-3-N are increased by 56.69%,31.48% and 23.94%,respectively,compared with the chemical fertilizer treatment,in summer.But in winter,the accumulation of NO-3-N are reduced by 67.38%,61.74% and 6.26%,in 0-10 cm,0-80 cm soil depth and edible celery parts,respectively.Different treatments have different magnitudes of annual variations of soil nitrate.The order from high to low is chicken manure> swine manure> commercial organic fertilizer> chemical fertilizer.Therefore,the application amounts of organic manures should be different in different seasons.The vegetable harvested in summer should be appropriate to reduce the application amount.On the contrary,the vegetable harvested in winter could be appropriate to increase the application amount.