New Arrangements for Soybeans Planting in North of Brazil.

The development of new soybean cultivars have raised questions regarding about  management of this crop in cultivation systems used. Cultivars with indeterminate growth, more precocious and with inclined leaf architecture, has shown necessity to revise and update the management system employed. The cross-seeding system has been used with success in Brazil productivity challenges and has presented good productive potential. Therefore, arrangement modification of soybean plants can generate significant increases, with sustainability, in current productivity. Thus the behavior of 3 soybean cultivars in 4 different layouts were tested: simple lines (population of 210,000 plants.ha^-1), single row narrow (population of 420,000 plants.ha^-1), crossover planting (population of 210,000 plants.ha^-1) and crossover planting narrow (population of 420,000 plants.ha^-1). Cultivars with determined and undetermined growth habit, and with different cycles were tested. The agronomic parameters (number of pods per plant, stem diameter, number of branches and productivity) were obtained to verify the cultivars behavior in arrangements tested. The experiments were conducted in three Brazilian cities located in North of Brazil: Palmas/TO, Pedro Afonso/TO Guaraí/TO. Early remarks showed reduction in stem diameter, height increase and a drop in pods number of soybean plants that growed under high density planting on simple line and in crossover planting. Crossover planting did not increase soybean yield. Studies with other arrangements (double rows or row spacing reduced) and cultivars (materials with high apical dominance that form few branches) should be conducted to check technical and economic feasibility of these arrangements. In this way, will be possible to recommend the best arrangement to increase the productivity of soybean crops in Brazil.