Theme 22: Grazing Management
Description
Beef and dairy cattle enterprises from tropical pasture-based systems are notoriously of low productivity. The low soil fertility, the exploitation of native grasslands, the low genetic potential of the animals and the poor management of soil, pasture and animal components are all arguments used to explain these “low-productivity systems”. In fact, research has consistently indicated up to 50% increase in calving rate when animals grazing unfertilized pastures were supplemented with trace-mineralized salt (Table 1) but unfortunately less than 90% of Brazilian farmers use this management strategy (Tosi, 1997). However, a recent survey conducted by São Paulo State government showed that almost 90% of farmers in the State use mineralized salt as a supplement (São Paulo, 1997). Similarly, well-fertilized and managed tropical pastures frequently have enough phosphorus in plant tissues to meet mineral requirements of most grazing animal categories (Table 2) and this might represent a significant reduction in mineral supplementation costs. Nevertheless, farmers do not frequently adopt use of fertilizers. A 1997 survey revealed that only 663.000 tons of NPK fertilizers were annually applied to 90 million ha of introduced pastures in Brazil, e.g., ca. 7,4 kg of NPK fertilizer/ha of pasture per year (ANDA, 1996/1997, cited by Ferreira et al., 1999).
Included in
Impact of Grazing Management on Productivity of Tropical Grasslands
Beef and dairy cattle enterprises from tropical pasture-based systems are notoriously of low productivity. The low soil fertility, the exploitation of native grasslands, the low genetic potential of the animals and the poor management of soil, pasture and animal components are all arguments used to explain these “low-productivity systems”. In fact, research has consistently indicated up to 50% increase in calving rate when animals grazing unfertilized pastures were supplemented with trace-mineralized salt (Table 1) but unfortunately less than 90% of Brazilian farmers use this management strategy (Tosi, 1997). However, a recent survey conducted by São Paulo State government showed that almost 90% of farmers in the State use mineralized salt as a supplement (São Paulo, 1997). Similarly, well-fertilized and managed tropical pastures frequently have enough phosphorus in plant tissues to meet mineral requirements of most grazing animal categories (Table 2) and this might represent a significant reduction in mineral supplementation costs. Nevertheless, farmers do not frequently adopt use of fertilizers. A 1997 survey revealed that only 663.000 tons of NPK fertilizers were annually applied to 90 million ha of introduced pastures in Brazil, e.g., ca. 7,4 kg of NPK fertilizer/ha of pasture per year (ANDA, 1996/1997, cited by Ferreira et al., 1999).
