ChileanJAR

The objetive of the present study was to determine those factors of the cultivar, soil, management and climate which: 1) affect the grain yield of the wheat (Triticum aestivum L.), and 2) modify the wheat response to nitrogen and phosphorous, in some "trumao" soils of Malleco and Coutin provinces (Chile). The way followed for this, was to establish a mathematic relationship -general regression equation- that expresses the yield as a function of applied nitrogen and phosphorous as fertilizers, and some cultivar, soil, management and climate factors. the data were obtained from 42 trials of wheat response to nitrogen and phosphorous. The trials were based on a treatment desing "square double" (5 doses of each nutrient and 13 treatments). The trumao soils studied were: Santa Barbara, Victoria, Agua Fria and Vilcun. the method used for producing the general regression equation, was that based on the "prediction sum of squares" porposed by Cady and Allen.