Abstract
When growing crops, soil water is remarkably well known to influence physical and chemical soil properties, whichi nfluences the fertilizer effect. The following equation (1) is expresses the relation with the amount of fertilizer and crop harvest quantity : y = b_0 + b_1N + b_2P - b_3N^2 - b_4P^2 + b_5NP (1) Where y is crop harvest quantity, N js nitrogen quality fertilizer, P is phosphorus acid quality fertilizer and b_i are constants. In order to know the quantitative relation between fertilizer and crop harvest, pot cultivations of wheat were tested using 3 irrigation water quantities. The resuits obtained are summarized as follows. 1) Equation (1) is proper as an equation to express fertilizer effect. 2) Equation (1) shows water content had a great influence on fertilizer effcctiveness. The harvest quantity of wheat didn't only be differ but also differed for the shape of Eq. (1) as fertilizer effectiveness. 3) Soil water greatly influences the effect of fertilizer. However, water has a greater effect on nitrogen quality fertilizer as compared to phosphorus acid quality fertilizer.
