SISTEMAS DE PRODUÇÃO DE SOJA EM SUCESSÃO A CULTURAS ANUAIS DE COBERTURA

Abstract

In Brazilian regions where the second harvest is possible, the predominant production system is the succession between soybean and corn crops. However, in general, this system generates low amounts of plant residues, which can compromise the viability of the no-till system (SPD) in the long run. The present work had as objective the soybean yield under different straw established in succession to the annual cover crops in the Brazilian cerrado. The study was conducted during the 2018/2019 agricultural year in the municipalities of Rio Verde-GO and Montividiu-GO. The evaluated treatments consisted of the following straws: Monoculture corn (M_Mn); Corn intercropped with Urochloa ruziziensis (M_Brz); U. ruziziensis monoculture (Brz_Mn); Sorghum intercropped with U. ruziziensis (S_Brz); Sorghum monoculture (S_Brz); Corn intercropped with U. brizantha cv. Marandu (M_Bmr); U. brizantha cv. Marandu monoculture (Bmr_Mn); Corn intercropped with U. brizantha cv. BRS Paiaguás (M_Bpg); U. brizantha cv. BRS Paiaguás monoculture (Bpg_Mn); Sunflower intercropped with U. ruziziensis (Gir_Brz); Crotalaria spectabilis (Crot_Mn); Millet; Mix (Milheto, C. spectabilis and U. ruziziensis), Fallow (Pou), in randomly distributed bands in the area. The agronomic characteristics of the soybean evaluated were: plantability, number and height of plants, the 1st pod height insertion, thousand grains mass and soybean grain yield. In Rio Verde-GO, regarding the number of plants and height, there were significant differences, with the highest values obtained in the treatments of the straws of Crot_Mn, Gir_Brz, Mix and M_Brz. For the 1st pod height insertion, there was a significant effect, highlighting the treatments with the highest heights at Brz_Mn, Bmr_Mn and Bpg_Mn. Regarding the thousand grains mass, a significant difference was observed with the highest value observed in the Crot_Mn straw with 181.42g. In the soybean yield in Rio Verde-GO there was a significant effect for treatments, with the straws of Gir_Brz and Mix and Crot_Mn presenting the highest grain yields with 4823.88, 5124.57 and 5719.70 kg ha-1, respectively. Regarding the grain yield in Montividiu-GO, the treatment with the straw from the plant mix showed the highest yield (3762.54 kg ha-1). The soybean plantability on the Bpg_Mn and M_Brz biomasses presented a regular result. The use of legumes associated or not with grasses as soil cover plants for the no-tillage system, grown in the off-season, provides better soybean crop performance.