Carlos Alexandre Costa Crusciol, Botucatu, College of Agricultural Sciences, São Paulo State University UNESP, Sao Paulo, BRAZIL, Adriano Stephan Nascente, Goias State, Embrapa Arroz e Feijão, Santo Antonio de Goiás, BRAZIL and Rogerio Peres Soratto, Crop Science Department, College of Agricultural Sciences, São Paulo State University – UNESP, Botucatu / SP, TX, Brazil
In tropical regions with dry winters, low plant biomass accumulation during the period between spring-summer crop cultivation can negatively impact soil resources and make the no-till (NT) system unsustainable. Palisadegrass (Urochloa brizantha) is a perennial forage specie that originated from Africa and has a vigorous, deep root system with high drought tolerance. Incorporating this palisadegrass in traditional Brazilian grain production areas could improve soil quality for the following crops with positive effects on grain yield. The objective was to evaluate soil fertility, plant nutrition, and grain yield effects of growing a perennial forage grass prior to five subsequent cash crops in a tropical region. The experiment was performed in Brazil following either, monocrop corn (Zea mays) or corn intercropped with palisadegrass, both grown for two consecutive agricultural years. An initial soil fertility evaluation in November 2004 was made when the land was either fallow (following monocrop corn) or covered by palisadegrass (intercropped areas). After the preceding treatments, the following crops were cultivated: soybean (Glycine max) during spring-summer for two agricultural years (2004-2005 and 2005-2006), white oat (Avena sativa) during fall-winter for two agricultural years (2005 and 2006) and corn during spring-summer for one agricultural year (2006-2007). The previous corn-palisadegrass intercropping increased the soil fertility compared to monocrop corn. Soybean, white oat, and corn all had higher leaf macronutrient concentration and grain yields in previously intercropped areas than following monocrop corn. We therefore recommend periodic, short-term incorporation of a perennial forage grass such as palisadegrass to increase grain production and provided other soil health benefits. We could see increases in crops yield even after three years of cultivating palisadegrass. When include palissadegrass by the intercropp with grain crops, it is also possible after harvest grain, to use the forage for cattle grazing or as straw in the growing season in the NT system.