豇豆苗期土壤氮磷钾安全含量估测与施肥量控制

Estimation of N,P,K Safe Content and Control of Fertilizer Rate at Seedling Stage of Cowpea

以"詹豇215"豇豆和5种肥料为试材,采用统计法研究在不同施肥水平下的土壤速效氮磷钾含量及豇豆幼苗空穴率,以期估测豇豆苗期土壤氮磷钾安全含量和科学指导施肥。结果表明:施肥水平不仅影响土壤中氮磷钾含量,还影响到豇豆移栽后的成活率,造成不同程度缺苗;复合肥对土壤肥力的影响作用最大,施用越多,速效氮磷钾含量越高,空穴率越高;速效氮磷钾含量与空穴率之间分别可以用线性关系式Y=0.007N-0.166、Y=0.007P-0.151和Y=0.003K-0.199表达。确保豇豆幼苗不发生肥害的土壤速效氮磷钾的上限含量分别为42.034、39.748、99.106 mg·kg^-1。复合肥(18-18-18)的每平方米用量与土壤速效氮磷钾含量可以分别用函数方程X=0.997N-11.315、X=1.042P-10.792和X=0.427K-13.083表达;在施用有机肥等肥料基础上,复合肥的最大施用量应控制在29.24 g·m^-2以内。

To estimate the N,P,K safe content at seedling stage of cowpea and scientifically guide fertilization,this study counted the contents of available nitrogen phosphorus and potassium in the soil and cavity rate of cowpea seedling under different fertilization levels using‘Zhanjiang 215’cowpea and five kinds of fertilizers as test materials.The results showed that the fertilizer level not only affected the nitrogen,phosphorus and potassium content in soil,but also affected the survival rate of cowpea after transplanting.Compound fertilizer had the greatest effect on soil fertility.The more the application,the higher the available nitrogen,phosphorus and potassium content,the higher the cavity rate.The available N,P,K content and the cavity rate could be expressed by the linear relationship of Y=0.007N-0.166,Y=0.007P-0.151 and Y=0.003K-0.199,respectively.The upper limit values of available N,P,K content in soil which the cowpea seedlings did not cause by fertilizer harm were 42.034,39.748,99.106 mg·kg^-1,respectively.The amount per square meter of compound fertilizer(18-18-18)and the available NPK content in soil could be expressed by functional equations X=0.997N-11.315,X=1.042P-10.792 and X=0.427K-13.083,respectively.On the basis of applying organic fertilizer and other fertilizers,the maximal amount of compound fertilizer should be controlled within 29.24 g·m^-2.