Mineral nitrogen in the soil and its effect on corn yield

Abstrakt

Experiments were conducted in a long-term stationary field experiment estab-lished at the experimental field of the Institute of Field and Vegetable Crops in Novi Sad in 1965. A part of the trial included corn monoculture, another part a two-crop rotation of corn and spring barley. This paper presents the results obtained in the period 1992-1995. The content of mineral nitrogen was found to depend on fertilization variant. The highest content of mineral nitrogen was found in the variants DVS+NPK and S+NPK, the lowest in the control variant. The distribution of mineral nitrogen along the soil profile varied among the test years and it depended on the amount of rainfall in the period preceding the growing season. The lowest grain yield was in the control variant. The effect of the applied mineral and organic fertilizers ranged in the monoculture from 132 to 156 %. In the variants NPK and MC-S-NPK, the highest yields were achieved with 120 kg N ha^-1; in the variants MC-M-NPK and DC-M-NPK, the highest yields were achieved with 60 kg N ha^-1. The mutual relationship between grain yield and the content of mineral nitrogen was high and it fitted the quadratic regression, while the correlation coefficients were high.