| Abstract: | Determination of Economical Optimum of Phosphate Fertilization on Loess and Loamy Soils 82 field trials with phosphate fertilizers on loess and loamy soils were evaluated to find out the economical optimum of fertilization. The evaluation in each trial was done by using the exponential function according to Mitscherlich with respect of profits and costs for yields and fertilizers. The result of this evaluation was, applied to the named soils, that the yield level has essential influence on the economical optimum of fertilization. Likewise the optimal P2O5 (CAL)-value in the soil is dependent on the yield level (CAL-value of group C), (Tab. 7). Accumulation of phosphate in soil caused by semi-liqued manure, magnesium content in soil, pH-value, and rainfall have a significant influence on the effect of mineral phosphate fertilization and on the reliability of prediction as well. Optimising resp. considering these factors and others are of supposition for exact evaluation of trials, for reasonable recommendation of both fertilization and threshold P2O5 (CAL)-value, and for critical examination of methods of soil analysis. |
