TKW Variation in Maize in Relation to Mineral Fertilization – Comparative Analysis

Abstract

The study evaluated the variation of the TKW (thousand kernel weight) parameter in corn in relation to differentiated mineral fertilization. The field experiment was placed within the ARDS Lovrin, in the climate and soil conditions specific to the Western Plain of Romania. The biological material was represented by the maize genotype 'DEKALB DKC 4109'. The maize crop was organized in a non-irrigated system, in the agricultural year 2024 – 2025. Mineral fertilization was done with phosphorus and potassium in autumn and nitrogen in spring. Phosphorus was applied in two doses (0, and 80 kg ha^-1 a.s.; a.s. – active substance). Potassium was applied in four doses (0, 40, 80, and 120 kg ha^-1 a.s.). Nitrogen was applied in three doses (0, 100, and 200 kg ha^-1 a.s.). The experiment included 16 experimental variants, in randomized blocks, in four repetitions. Sowing was done on April 15, 2025, with a density of 65000 plants ha^-1. Uniform crop technology was applied for the experimental variants. At harvest maturity, 9 BBCH Code, corn cob samples were taken from each experimental variant and repetition. Subsamples were extracted from the grain samples on which the values ​​of the parameter TKW (thousand kernel weight, g) were determined. The average values, by experimental variants, were analyzed in the study. The thousand kernel weight values ​​ranged from TKW = 211.20±3.09 g (V9) to TKW = 262.40±3.09 g (V14). The data series presented a normal distribution, with r = 0.980. No outliers were recorded, according to Grubbs test (G = 2.286; p = 0.195), respectively Dixon Q test (Q (r22) = 0.4804; p = 0.119). Polynomial models described the variation of TKW in relation to NPK, as variables in different combinations. Convergent contribution was recorded for N and P in the TKW variation, and divergent contribution was recorded for N and K, respectively P and K in the variation of TKW. The comparative analysis highlighted five variants with differences above the mean value (V7, p<0.01, **; V13, p<0.01, **; V14, p<0.001, ***; V15, p<0.001, ***; V16, p<0.01, **), and four variants with differences below the mean value, under conditions of statistical safety. Cluster analysis grouped the variants based on similarity in relation to TKW values.