Optimization of nitrogen nutrition system elements for maize hybrids in the conditions of Sumy region

Abstract

The article presents the results of two-factor field trialsaiming to substantiate the optimal nitrogen nutrition systemfor maize under the soil and climatic conditions of the North-Eastern Forest-Steppe of Ukraine. The study evaluated theimpact of pre-sowing application of various urea doses (100and 200 kg/ha) on growth processes, biometric parameters,yield structure components, and grain productivity of threemodern maize hybrids belonging to different maturity groups:DKS 3730, DKS 4590, and DKS 5075. Field trials were conductedon typical medium-humic chernozems characterizedby a medium content of easily hydrolyzable nitrogen and anelevated content of available phosphorus and exchangeablepotassium. It was established that the applied dose of nitrogen fertilizersignificantly stimulates linear plant growth and positivelyinfluences grain fullness. The highest growth activity and productivityacross all nutrition backgrounds were demonstratedby the high-yielding hybrid DKS 5075. Under pre-sowing ureaapplication at a dose of 200 kg/ha, its plant height reached275 cm, the 1000-kernel weight increased to 340 g, and grainyield achieved the maximum trial value of 14.0 t/ha (a 3.2 t/haincrease over the unfertilized control). For hybrids DKS 4590and DKS 3730 under the same nutrition background, grainyields were 12.8 t/ha and 12.4 t/ha, respectively.An analysis of fertilizer payback demonstrated thatthe highest yield increment per unit of applied nitrogen(1.3–1.8 t/ha) was achieved with a moderate urea dose of100 kg/ha, whereas a further increase to 200 kg/ha resultedin a smaller additional gain of 0.9–1.4 t/ha depending onthe hybrid. The research findings confirm the high efficiencyand economic feasibility of an adaptive approachto maize mineral nutrition based on the genetic potentialof a specific hybrid.