In regions with a tropical climate, the greatest limitations for straw maintenance on the soil surface are difficulties on its establishment and high rates of decomposition. With the aim of identifying the productive potential of Xaraes and Ruziziensis grasses, as well as subsequent straw formation for continuity of the no-tillage system, the following factors were evaluated: the dry matter yield, the lignin/total N ratio, macronutrient accumulation, and straw decomposition in two growing seasons. The treatments consisted of two Brachiaria species (Brachiaria brizantha cv. Xaraés and Brachiaria ruziziensis), intercropped with corn and fertilized at the same nitrogen rates (0, 50, 100, 150, and 200 kg ha-1 of N) during and after intercropping with corn. The time for decomposition of the straw over the period of 120 days was evaluated by the "Litter bag" method. Nitrogen fertilization did not affect the dry matter yield of Xaraes and Ruziziensis grasses, the lignin/ total N ratio, and the amount of straw deposited on the soil surface after intercropping with corn; however, it increased the accumulation of N, K, Mg, and S. The Xaraes and Ruziziensis grasses have potential for straw production above 4,000 kg ha-1 between crop seasons, maintaining 15-60 % of this amount at 120 days after crop harvesting.
Brachiaria brizantha cv. Xaraés; Brachiaria ruziziensis; no-tillage system
