Methodology for Estimating Corn Response to Nitrogen Fertilizer

A method for assessing the responsiveness of corn to nitrogen fertilizer has been developed. In 2012-2015, the All-Russian Corn Research Institute studied corn hybrids of different ripeness groups on the basis of responsiveness to nitrogen fertilizer. Corn hybrids were grown in a field experiment on 2 backgrounds: 1 - control without fertilizer and 2 - N60. As quantitative signs of responsiveness to fertilizer, the height of plants in the flowering phase, the yield of green mass in the phase of milk-wax ripeness and grains in the phase of full ripeness were used. The indicator of the reaction of corn to nitrogen fertilizer was calculated by the formula:

$Пр=\frac{(в{р}_2-в{р}_1)}{в{р}_1}\times 100+\frac{(з{м}_2-з{м}_1)}{з{м}_1}\times 100+\frac{(у{з}_2-у{з}_1)}{у{з}_1}\times 100,$

where Пр is an indicator of the reaction to nitrogen fertilizer; вр₁, вр₂ - the height of corn plants, respectively, in the control and on a fertilized background; зм₁, зм₂ - the yield of green mass in the milky-waxy ripeness of corn in the control and on a fertilized background; уз₁, уз₂ - the grain yield of corn samples in the control and on a fertilized background. According to the parameters of the reaction to nitrogen fertilizer, highly responsive forms of corn were identified: Mashuk 355 MV and Mashuk 390 MV hybrids. The method for assessing the responsiveness of corn to nitrogen fertilizer is protected by Patent No. 2744730 dated March 15, 2021.