Production systems for corn second crop intercropped with Urochloa ruziziensis, involving crop rotation with cover crops, rice and soybean

The production system based on the succession of cultures as well as the sequence between corn and soybean in Brazil, does not hold up over the years. Thus, the inclusion of cover crops, and rice cultivation by replacing part of the soybean area may be options to benefit the agricultural system in the Cerrado. The objective was to evaluate the adoption of cover crops in the cultivation of upland rice, soybean and the effect on maize second crop intercropped with Urochloa. The project consisted of three subprojects. Subproject 1: Production systems for upland rice with the use of cover crops. Subproject 2: Soybean production systems with the use of cover crops. Subproject 3: Maize second crop intercropped with Urochloa ruziziensis cultivated on rice and soybean straw, as a function of cover crops. Six cover crops were used [millet (Pennisetum americanum), sunn hemp (Crotalaria juncea), pigeon pea (Cajanus cajan), millet + sunn hemp, millet + pigeon pea and fallow] soothed in the spring. The experimental design for rice and soybean was randomized blocks, with six treatments and 4 replications. The design for maize was randomized blocks, with a scheme in strips, with 4 replications. The study was conducted in Selvíria - MS in the Cerrado region, on a Oxisoil, conducted from September 2014 to September 2016, with the use of supplemental irrigation. Subproject 1 – In the cultivation of upland rice, the consortium millet + sun hemp provides greater accumulation of straw, macronutrients, besides keeping larger amount of straw on the ground and promote greater release of nutrients within 120 days after sowing rice. The sun hemp cultivation in the winter/spring, favors the largest total number of spikelets per panicle and grenades, as well as benefit the productivity of rice grains. The physical condition of the soil in 2015/16, is improved by the cultivation of pigeonpea before the rice crop. Subproject 2 - The accumulation of straw and nutrients by sun hemp and soil cover maintenance and release of nutrients are hampered by succession to soybeans, while soybeans benefits millet cultivation. The pigeon crop, prior to soybean favors the physical conditions of the soil in relation to fallow and millet. Subproject 3 - The accumulation of straw and soybean cycling of N, P, Ca and Mg are higher than rice straw. Cultivation of upland rice can be an alternative to the summer into rotation with soybeans, resulting average productivity of 4,071 kg ha-1 and the potential to produce 5,619 kg ha-1 of straw on the soil. In the region of low altitude Cerrado, with the use of supplementary irrigation, the production system with cover crops, rice/soybean and corn in intercropped with U. ruziziensis, enables input of approximately 20 t ha-1 yr-1 of ground straw and about 9,350 kg ha-1 yr-1 of grains. (AU)