A first approximation to a quantitative model for forecasting the yield response of the potato to fertilizers in Romania

A first approximation to a multidimensional statistical model regarding potato tuber yield is described. The model is represented by a second-order quadratic equation with 74 terms, including 17 factors of technology of cropping, of soil and climate. In the computerization of the 74 coefficients, data are included from 2000 experimental plots on which fertilizer applications have been studied in zones of the country differing considerably in soil and climate. The model can be used in solving NPK manure equations for every plot; by these quadratic equations the optimization of NPK manure applications may be made for every plot in a farm. The natural potential yields without fertilizers can also be calculated and the country zoned for its natural potential. An example is provided which demonstrates that the model describes reasonably accurately the effects of climate and soil on tuber yield and the necessary amount of fertilizers. The solutions of the model agree with our present agronomical knowledge.