Establishment and initial development of Andropogon gayanus pastures in tropical savannas

Andropogon gayanus is a species of grass that is well adapted to the soil and climatic conditions that characterize the well-drained savannas of tropical America. Once established, the grass has a high productive potential and low nutritional requirements. It tolerates soil acidity and is very persistent. However, during establishment, it is not vigorous and is slow growing. This chapter reviews research performed on, and experiences with, establishing and developing pastures based on A. gayanus. Land clearing is studied and tillage systems that vary from the traditional to no tillage are reviewed. Also considered are plot preparation times, sowing times, and sowing and fertilizing methods. The importance of sowing standards and fertilizing methods for the crop is discussed. Although there is little information on establishing A. gayanus in association with annual crops, its establishment in association with forage legumes, particularly Pueraria phaseoloides and various species of the Centrosema and Stylosanthes genera, is discussed. Attention is given to the system of low-density planting-a particularly valuable system in those areas of the savanna where there is a scarcity of seed and where weeds are not a problem. To conclude the chapter, a brief description is given of the problems caused by pests, particularly ants which constitute one of the most serious constraints to establishing A. gayanus in the savannas.