MODELS FOR DESCRIBING THE VARIATION OF MOISTURE IN WHEAT GRAINS DEPENDING ON MINERAL AND FOLIAR FERTILIZATION

Abstract

The study evaluated the moisture content of wheat grains in relation to mineral nitrogen fertilization and foliar fertilization. The biological material was represented by the Alex wheat cultivar. By mineral fertilization, five nitrogen levels were ensured, in the range 0 - 200 kg a.s. ha-1 (a.s. - active substance). Super Fifty (SF) biofertilizer was applied foliar in six concentrations, ranging from 0 to 5 l ha-1. The combination of the two fertilizing resources resulted in 30 experimental variants, in three repetitions. The moisture content (M, %) of the wheat grains was evaluated, in relation to the applied fertilization. Regression analysis was used to estimate the humidity (M,%) in relation to SF on each nitrogen (N) level. Grains moisture estimation (M, %) was possible in conditions of R2 = 0.681, p = 0.043 on the level of nitrogen N0, and in conditions of R2 = 0.999, p <0.001 on the other levels of nitrogen fertilization (N50 - N200). According to the calculated prediction error (PE) and the RMSEP statistical parameter, the highest safety in estimating grain moisture relative to SF was at the N150 level, where PE = -0.14, and RMSEP = 0.049163. The variation of moisture (M, %) in relation to N and SF, evaluated on the data set as a whole, was described by an equation of type M (%) = ax2 + by2 + cx + dy + exy, in statistical safety conditions, R2 = 0.917, p <0.001. A graphical distribution was obtained, in the form of a 3D model and in the form of isoquants of the moisture M (%) variation in relation to N (x-axis) and SF (yaxis). Based on PCA, PC1 explained 42.523% of variance, and PC2 explained 32.781% of variance in relation to N doses, respectively PC1 explained 63.936% of variance, and PC2 explained 23.776% of variance in relation to SF.