Planting Spacing of Cultivated Soybean Intercropped with Cover Plants

Aims: The objective of this work was to evaluate the influence of planting spacing in soybean intercropped with covering species in the Roraima savanna.

Study Design: The experimental design was a randomized complete block design with four replications.

Place and Duration of Study: The experiments were conducted at Embrapa Roraima, in Campo Experimental Água Boa, municipality of Boa Vista - Roraima state, in 2015 and 2016.

Methodology: Plots consisted in the spacing (0.45, 0.55 and 0.65 m) and the subplots were constituted by the cover plant species Urocloa brizantha, Urocloa ruziziensis, Panicum maximum and the treatment without intercropping. The used soybean cultivar was BRS Tracajá in two crops. The following variables had evaluated: plant height, number of grains per pod, number of pods per plant, 100-grain weight, plant dry matter, insertion of the first pod, grain yield, and dry matter of the covering species and of spontaneous vegetation.

Results: Cover plants affected the plant height, number of pods per plant, insertion of the first pod, dry matter of cover species and yield of grains in soybean. The spacing did not influence the growth and production of the soybean crop, except positively in the number of pods per plant with the increased of spacing. The interaction of cover plants and spacing affected the weight of 100 grains, the insertion of the first pod and the dry mass of the cover species. Number of grains per pod and the dry mass of the soybean plants were not affected by the cover plants and by the spacing.

Conclusion: The U. brizantha species provids the highest production of dry matter intercropped with soybean, however, the yield of the crop decrease. The U. ruziziensis species is the most suitable for the cultivation intercropped with the crop. The used spacing do not influence the productivity.