[Mobile phosphorus content in soils for sustained crop production]
1997
Borlan, Z. | Gavriluta, I. | Stefanescu, Daniela | Nebunelea, Dobrita (Institutul de Cerecetari pentru Pedologie si Agrochimie, Bucuresti (Romania))
Dealing with P requirements of crops for sustainable productions the paper advocates that phosphorus supplying power of the soil, as reflected by quantity (Q=PAL) and intensity (I=P-CaCl2 0,01M) relationships should increase in pace with yielding level of crops. This was thought appropriate due to positive correlations between P diffusion in the soil, P uptake in plants and P mobility in the soil as reflected by I/Q ratio. Starting from crop yield regression on chemical soil testing (PAL) data and on P fertilizer rates applied in long duration field experiments, authors proposed algorithms to estimate the need of efficient phosphorus (Ps, kg P2O5/ha) from all available sources (soil, organic and factory-made fertilizers) and also the levels of mobile P (PAL, ppm P) in the soil to meet the requirements of crops for 0,9 and 0,95 parts of yield expectancy under the conditions of sustained production.
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