A comparison of the nutrient levels of various pasture grasses and legumes as related to soil type and fertility - interim report
1981
Neal, R.H. (Ministry of Agriculture and Lands (Belize))
Grass and legume samples harvested from 8 different trial sites on Alfisols, Vertisols and Ultisols over the wet and dry seasons in Belize were analysed for tissue content of nitrogen, phosphorus, potassium, calcium, magnesium, manganese, copper, zinc and sulphur. Legumes accumulated higher concentrations of N than grasses, crude protein being 15 percent of dry matter in legumes and 6 percent in grasses, indicating that nitrogen fixation occurred. The elements thought to be crucial, phosphorus (P), copper (Cu) and Zinc (Zn) were discussed. P levels were deficient for both plant requirements and beef cattle production, at 0.14 percent and 0.19 percent DM in grasses and legumes respectively. This indicates the importance of using phoshate fertilizers and P-supplementation in cattle diets. Tissues were found to be deficient in Cu at 6.9 ppm in legumes and 3.7 ppm in grasses whereas 10 ppm is widely accepted to be the critical value for cattle nutrition. Zinc was a stable constituent with little difference in the Zn contents of grasses and legumes (34 ppm). Zn supplementation is recommended only if deficiency signs are demonstrated as this deficiency is rare in grazing cattle. There were no obvious differences in plant mineral concentrations between the wet and dry seasons
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