施肥和秸秆还田对黑土农田土壤剖面养分分布的影响

以东北黑土区玉米田为对象,利用田间原位小区试验,结合亮蓝染色示踪技术,研究不施肥(CK)、常量化肥(T₁)、化肥减施秸秆还田(T₂)、化肥减施秸秆还田配施有机肥(T₃)条件下,土壤剖面的养分分布特征及其对施肥措施和秸秆还田的响应机理。结果表明:与CK相比,各施肥处理均显著增加了玉米产量,但不同处理之间耕层土壤全量养分无显著差异;与CK相比,常量化肥处理可提高40～80 cm土层土壤硝态氮含量,化肥减量配施有机肥结合秸秆还田则可提高0～100 cm土层速效钾含量及0～40 cm和80～100 cm土层硝态氮含量;不同处理间土壤基质流无显著差异,施用有机肥和秸秆还田会影响土壤优先流,但3个施肥处理间差异不显著,施用有机肥会促进土壤孔隙度增加和优先流的形成,增加养分的垂直运移。

Effects of fertilization and straw return on nutrient distribution along soil profile in black soil croplands

An in situ field experiment combined with the brilliant blue staining tracer was conducted to study the distribution of soil nutrients and its response mechanism to fertilization and straw return under no fertilization(CK),conventional chemical fertilizer(T₁),NPK reduction plus straw return(T₂),and NPK reduction with straw return and organic manure(T₃)in maize croplands in black soil region of Northeast China.The results showed that compared with CK,the treatments with fertilization and/or straw return significantly increased maize yield.There was no significant difference in total nutrient content of plough layer among different treatments.Treatment T₁increased soil nitrate content of at the 40-80 cm layer,while T₃increased available K content of in 0-100 cm soil layers and nitrate content in 0-40 cm and 80-100 cm soil layers.There was no significant difference in soil matrix flow among different treatments.Organic manure and straw return affected soil preferential flow,but without difference among the three fertilization treatments.Application of organic manure can promote the increase of soil porosity and the formation of preferential flow,facilitating the vertical transport of soil nutrients.