THE EFFECT OF CROP YEAR AND FERTILIZATION ON THE INTERACTION BETWEEN THE SPAD VALUE AND YIELD OF MAIZE (ZEA MAYS L.) WITHIN NON-IRRIGATED CONDITIONS

Fertilization reliably increased the SPAD values of maize hybrids in all three years of the striped long-term field experiments having three factors and Four repetitions, adjusted on chernozem soil with lime deposits on the Latokep experiment site of the University of Debrecen, Centre of Agricultural Sciences and Engineering. The SPAD values reliably differed from each other in every year, that was indicated by the significant hybrid x fertilizer interaction. The biggest SPAD value was gained with a N-150 kg/ha fertilizer-active ingredient treatment (56,2), nevertheless, the SPAD value gained with a fertilizer dose of N-120 kg/ha is not significantly lower, therefore N-120 kg/ha is also suitable to develop the maximum SPAD value. The R-2 value gained on the basis of linear regression was 0,605. Fertilization significantly modified the grain yield of maize in all three years. During the examination of the relationship between SPAD value and yield data, we concluded that there is a stochastic relationship between them (r=0,449). Considering the value of the determination coefficient (R-2), we stated that SPAD value determined the yield quantity to an extent of 20,2% in the average of the three years. Based on the values we got, we arrived at the conclusion that yield quantity increases with the increase of SPAD value. The biggest yield was reached above a SPAD value of 55 in the average of three years.