Fitossociologia de plantas espontâneas em consórcio de adubos verdes com milho

Abstract

Green manures can be an alternative for the sustainable management of spontaneous plants intercropped with corn. The objective was to evaluate the influence of green manure intercropped with corn on the population dynamics of weeds. The experiment was conducted in an experimental area at the Fazenda Escola de São Luís at the State University of Maranhão, between January and April 2018 during the rainy season. The area is located in the municipality of São Luís - MA. The area was prepared with mowing followed by opening pits spaced one meter apart and fertilized with 60 kg ha -1 of N in the form of urea, 100 kg ha -1 of P 2 O 5 as simple superphosphate and 80 kg ha -1 of K2O as potassium chloride. At 40 days after emergence (DAE) the crop was topdressed with 30 kg ha -1 of N in the form of urea. The corn variety used was Sol-da- Manhã launched by Embrapa to meet nitrogen deficiency in family farming, which has a height of 2.20 m, insertion of ears of 1.20 m, cycle of 130 days. Corn sowing was manual with three seeds per hole and thinning was performed leaving one plant per hole. The green manure sunn hemp, cowpea, jack bean, mucuna, adzuki bean and lablab were also sown manually at 20 DAE between the rows of the corn crop, using 4; 4; 3; 3; 4-5 and 3-4 seeds per hole with 10 spacing between plants; 20; 40; 40; 20 and 40 centimeters, respectively. The design was in randomized blocks with four replications and the green manures, Vigna unguiculata, Canavalia ensiformes, Mucuna nivea, Vigna angularis, Crotalaria juncea, Mucuna deeringiana var. dwarf, Crotalaria spectabilis and Dolicho lablab intercropped with maize and a control without green manure. It was therefore concluded that the green manure that obtained the greatest result in changing the population dynamics of spontaneous plants in the intercropping system with corn was Crotalaria juncea, being a great producer of biomass. The main species in the spontaneous community in the intercropping of green corn with green manures are D. ciliares and A. tenella, E. indica and P. trichoides. It is feasible to use green manure in intercropping with green corn to suppress weeds, as green manures reduce the germination of weeds, thus promoting the development of green corn