Cover crop influence on nutrient cycling, nematode population and soybean yield in the Brazilian Cerrado

Abstract

Soybean-maize succession is the main annual cropping system used in Brazilian cerrado. However, due to water restrictions, the cultivation of maize (off-season crop) is not viable after cultivation of late maturing soybean cultivars and/or when late soybean seeding occurs due adverse weather conditions. In this scenario, the use of cover crops can be a good option to benefit soil health and consequently the soybean yield in the next crop season. The objective is to evaluate the effects of cover crops on biomass inputs, nutrient cycling, and nematode control during the off-season in the Cerrado biome. The study was conducted for three years in two locations in the state of Goiás. We evaluated five options of cover crops after soybean cultivation: 1) Mix of cover crops (Pennisetum glaucum, Crotalaria spectabilis, and Urochloa ruziziensis), 2) P. glaucum, 3) C. spectabilis, 4) U. ruziziensis 5) U. brizantha cv. Marandu, and 6) U. brizantha BRS Paiaguás. The results revealed that Pennisetum glaucum (9633 and 6958 kg ha-1 in Montividiu and Rio Verde) and U. brizantha cv. Marandu (8015 kg ha-1 in Rio Verde) produced the highest amount of biomass on average over three years. The treatments soybean/Crotalaria spectabilis and soybean/Pennisetum glaucum reduce the population of the nematodes. However, the use of a more diversified system such as the mix of cover crops provided a greater soybean yield, soil coverage and a high concentration and release of nutrients during the soybean cycle. Being one important alternative for ensure agricultural sustainability in the Cerrado.