COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS, cilt.48, ss.929-935, 2017 (SCI-Expanded)
It is crucial to know how management factors influence soil test phosphorus (P) since non-point P sources for surface waters are becoming recognized as a problem throughout the USA. Phosphorus fertilizer and crop residue can impact the cycling of P in soils. An eight-year crop residue removal and P fertilization (0, 7.3, 14.7 and 29.4kg P/ha) as triple superphosphate (TSP) experiment were conducted to determine the effect of P applications on soil P fractions. Significant differences in Bray-l extractable P were observed after only one year of P applications. Extractable P at the highest P rate was significantly higher than all the other rates. For each 5.6kg P/ha added or removed, Bray-l P changed by 1mg/kg. Fertilizer P applications did not significantly change the organic P (P-o) levels, microbial P (P-m) or soil pH, whereas residue treatments had effects on them except for soil pH. Residue-retained plots had significantly higher P-m in the last two years of study, and P-o in the 8(th) year, compared with residue-removed plots.