Effect of liquid multiple-nutrient fertilizers on maize grain quality and nutrient removal on different agroecological groups of lands

The effect of liquid multiple-nutrient fertilizers NPK 7:23:7 in combination with urea-ammonia liquor (UAN) KAS-32 + NS 8:9 on the quality indices and chemical composition of maize grain is discussed. A mineral nutrition system was developed based on the application of NPK 7:23:7 at planting as starting fertilizer and inter-row dressing with the UAN KAS-32 + NS 8:9. The experiment was carried out in the Krasnodar Region from 2021 through 2023 under production conditions when growing maize for grain (mid-season simple maize hybrid DKS 4964). The experimental design included 2 factors: the nutritional scheme (fertilizers) and the agro-ecological group of lands. To conduct the study, several plots belonging to different agro-ecological groups were selected: upland and eroded lands. After harvesting, the following quality indices were determined: crude protein, crude fiber, crude fat, and the chemical composition: nitrogen, phosphorus and potassium content levels. Increasing nitrogen fertilizer rates, in variants with the use of liquid fertilizers, significantly increased the nitrogen content in grain from 1.19% in the control variant to 1.51% in the variant with the use of liquid fertilizers. However, the factors of liquid fertilizer application and the group of lands did not significantly affect the content of phosphorus and potassium in the grain. Along with the increasing nitrogen content, the content of crude protein increased from 11.0 to 12.5%, as well as its yield from one hectare to 1114 kg ha. The content levels of crude fiber and crude fat did not depend on the nutritional pattern and agro-ecological group of the land. The application of liquid fertilizers had a significant impact on the amount of total nutrient removal as well as on the ratio of nutrients. The use coefficients of nitrogen from liquid fertilizers turned out to be approximately 67%, while from ammonium nitrate it was 52%. The eroded group of lands reduced the use coefficients of nitrogen and potassium by approximately 10% while it did not have a significant effect on phosphorus absorption.