Theme 18: Agro-Silvipastoral Systems
Description
The aim of this work was to compare the annual biomass production and nutrient removal of a Dichanthium aristatum pasture with those of a pasture of the same species associated with a leguminous tree, Gliricidia sepium. Measurements were made over twelve months between April 1993 and April 1994. Sampling was done with the same defoliation frequency as an intensive cut-and-carry system: every 4 and 10 weeks for the grassland and tree layers respectively. There was no significant difference between the yield of the pure grass (21.6 ± 2.0 t ha-1) and that of the grass with trees (18.2 ± 2.9 t ha-2). On the other hand the amounts of nitrogen removed by the Dichanthium grown with trees was very much greater than for the natural pasture: 167.3 ± 2.7 kg ha-1 and 114.8 ± 1.1 kg ha-1 respectively. The amounts of potassium and phosphorus removed by the grass grown with Gliricidia were also greater, but only significantly so for the former. Leaf production and nitrogen removed by the trees were 26.8 t ha-1 and 788.3 kg ha-1 respectively. It was shown that in this type of farming system, recycling of the nitrogen fixed by the trees via leaf-fall is negligible. These results confirm the value of the association between leguminous trees and grasses in tropical humid/sub-humid livestock systems since they increase the general production efficiency of the system as well as that of the grass layer itself.
Included in
Annual Dry Matter and Nutrient Yields in a Dichanthium Sward with or without Gliricidia Shrubs
The aim of this work was to compare the annual biomass production and nutrient removal of a Dichanthium aristatum pasture with those of a pasture of the same species associated with a leguminous tree, Gliricidia sepium. Measurements were made over twelve months between April 1993 and April 1994. Sampling was done with the same defoliation frequency as an intensive cut-and-carry system: every 4 and 10 weeks for the grassland and tree layers respectively. There was no significant difference between the yield of the pure grass (21.6 ± 2.0 t ha-1) and that of the grass with trees (18.2 ± 2.9 t ha-2). On the other hand the amounts of nitrogen removed by the Dichanthium grown with trees was very much greater than for the natural pasture: 167.3 ± 2.7 kg ha-1 and 114.8 ± 1.1 kg ha-1 respectively. The amounts of potassium and phosphorus removed by the grass grown with Gliricidia were also greater, but only significantly so for the former. Leaf production and nitrogen removed by the trees were 26.8 t ha-1 and 788.3 kg ha-1 respectively. It was shown that in this type of farming system, recycling of the nitrogen fixed by the trees via leaf-fall is negligible. These results confirm the value of the association between leguminous trees and grasses in tropical humid/sub-humid livestock systems since they increase the general production efficiency of the system as well as that of the grass layer itself.
