Search

Extreme drought or rainy seasons affect the efficiency in the stockbreeding systems whose forage production is based on the grass monoculture. These species are more vulnerable to the extreme climate conditions, which requires looking for alternative plants with higher resistance to these conditions. This work studied the Cratylia argentea performance in forage banks used in degraded soils with high amounts of agrochemicals in areas of tropical rainforest. The study took one year and was conducted in the estate Matapantano, located in Yopal, Casanare (Colombia). The effect on the physical-chemical properties and macrofauna in this soil, the green forage and dry mass production, the leaf-stalk relationship, the nutritional quality of both fractions (leaf-stalk) and the whole plant were studied. A random design and the software Infostat® were used for the descriptive statistics and the non-parametric variance analysis. The soil showed increases in the contents of minerals, organic mass, organic carbon and macrofauna. Differences were observed in the dry mass production from the plant fractions (p < 0.0001), in the dry mass production between cuts (p < 0.0001) and in the leaf-stalk relationship (p < 0.0001). The forage showed a good nutritional quality and the leaves were the fraction with best quality. C. argentea resisted the extreme changes in the climate conditions. It is concluded that the studied species has a good potential for the recovery of degraded soils with intense use of agrochemicals as it produced good quality forage to feed animals in stockbreeding systems, even in the drought season. [ABSTRACT FROM AUTHOR]

In order to evaluate the effect of defoliations on forage production, structure and efficiency of radiation and water utilization of Digitaria eriantha Steudel spp. eriantha cv. Irene, a trial was conducted at the National University of San Luis, Villa Mercedes campus, -San Luis, Argentina-. Three defoliation treatments were evaluated: cycle end (CCC), in mean leaf lifespan (CMLL) and at fixed time every 30 days (CFT). There were significant differences in forage production, total mass and number of cuts (p < 0,05) for CMLL, cCc and CFT (1 100 g DM/m²; 912,693 g DM/m²; and 4, 1 and 6 cuts, respectively). The high frequencies altered the vertical structure, by decreasing stem production; and the horizontal structure, by increasing the tiller density, with lower total biomass production. CFT improved L/S (CFT: 45,45 vs. CMLL: 16,13) and increased tiller density (CFT: 3 773 vs. CMLL: 2 264 tillers/m²). CMLL did not show alterations on the horizontal structure, but the interception (CMLL: 0,85 vs. CCC: 0,97) and radiation capture were weakened with regards to CCC; nevertheless, it generated high leaf production which allowed to maximize the efficiency of water and radiation use (1,38 g DM/m²/mm and 1,30 g DM/MJ, respectively). Defoliation management influences the crop structure and has incidence on the forage offer. Managing forages under morphogenetic concepts induces a balanced utilization of production and quality, and improves the efficiency of the use of environmental resources. [ABSTRACT FROM AUTHOR]