Growth and grain yield of canola overseeded on soybean

Abstract

The overseeding technique allows the establishment of a crop before the harvest of an overseeded crop at the end of the cycle. It aims at making a better use of more favorable seasonal climatic conditions and the intensification of cultivation systems, with the possibility of obtaining another harvest in less time. This work aimed to verify if it is possible to establish the Brassica napus crop in overseeding with the phenological stages at beginning of grain filing (R5) and beginning of soybean physiological maturation (R7) in the Central region of the state of Rio Grande do Sul. The study was performed in a Humid Subtropical climate, in Santa Maria, RS. A randomized block design was used, in a 4 x 2 factorial arrangement with 4 replications, with four seed Brassica napus densities (3, 6, 12, and 18 kg ha-1) and two developmental stages of the soybean crop (R5 and R7), in addition to the control treatment sown in rows directly on the straw right after soybean harvest (3 kg ha-1- standard). The plant density, yield components, and grain yield were measured. The canola crop is not established when overseeded in the soybean stage R5. The seed density of 6 kg ha-1 achieved the recommended plant density for the canola overseeded in stage R7 of the soybean crop. The 6 kg ha-1 density stood out as the best treatment performed in the R7 stage of the soybean crop.