COVER CROPS AND NPK FERTILIZATION ON CORN UNDER NO-TILLAGE MANAGEMENT

Abstract

This study aimed to evaluate the use of cover crops grown in the preharvest period and different doses of the fertilizer NPK on the yield of corn hybrid P 30K75 grown in direct plantation, in high population densities, in the Cerrado of Ipameri-GO. It was conducted a field experiment in a dystrophic red-yellow latosol. The statistical design was a randomized block in split-plot experimental scheme with three replications. The main treatments consisted of three species used as cover crops (Crotalaria juncea, Crotalaria spectabilis and Brachiaria decumbens) and the secondary treatments were five different doses of the NPK fertilizer (D1 = 60 +50 +30 , D2 = 120 +100 +60; D3 = 144 +120 +72, 180 +150 +90 = D4, D5 = 300 +250 +150 kg ha^-1 N + P₂O₅ + K₂O). The dry matter of the cover crop (80 days after sowing) was 6271, 5197 and 6383 kg ha^-1 for C. juncea, C. spectabilis and B. decumbens, respectively. The effects of NPK doses and coverage plant species on the development and corn yield were independent. The cover crops  C. juncea and C. spectabilis provided better development and productivity of maize than Brachiaria. The increasing in NPK levels promoted better development and increased the productivity of maize.