The role of fertilization on phosphorus stratification in no‐till soils

Abstract

No‐tillage induces the stratification of soil nutrients because of the return of crop residues to soil surface, fertilization and the lack of soil mixing. In this research we have attempted to develop a phosphorus (P) balance on soybean, to study the relative importance of the causes of P stratification. An experiment was performed on a Typic Hapludoll located in mid Buenos Aires province, Argentina. The treatments were fertilized and unfertilized. Soybean biomass and P concentration in grains, stubble and roots were determined. In both treatments the P stratification was produced by the enrichment of the surface layer and the impoverishment of the deeper layers. In the non‐fertilized plots the soil lost P (7.5 kg P ha¹) meanwhile in the fertilized plots (20 kg P ha^‐1added) the soil gained P (6.6 kg P ha^‐1). The accumulation of plant residues alone is enough to redistribute P in soils, but fertilization was the main factor in P stratification.