Evaluation of sources of nitrogen and times of application in top dressing for the cultivation of the wheat

Abstract

The objective of this work was to test sources of nitrogen and application times in top dressing for the wheat crop in the area of Mauá da Serra-Pr. It was used wheat 'CD-104' in direct sowing system, using a spacing between plants of 0.17 m and a density of 350 seeds m-2, being accomplished a base fertilizer applying 400kg ha-1 of the formulated fertilizer 10-20-10. The treatments had been constituted of 3 sources of nitrogen (Urea, Sulfate of Ammonium and Nitrate of Ammonium), applied in broadcasting in 3 different times (soon after the sowing, in the tillering and in the booting), resulting in 9 treatments. Each parcel was constituted by an area of 4.0m x 5.0m being considered as useful area the 5 central lines. The used experimental design was of blocks at random with 4 replications . There are no differences in the yield of grains among sources of N not even for the application times. The late application at the booting of the crop caused a production of grains of better quality with larger weight and protein content.