Abstract:
A field experiment was conducted to determine the associative effects of Panicum maximum (Guinea A) when grown in association with Calliandra calothyrsus. Planting of fodder grass (P. maximum Guinea A) in an existing Calliandra (6 years old) plantation was done according to a line-planting array. Guinea A was selected due to its natural abundance. Trees were pruned at 50 cm height above ground level before planting of grass. The experimental plots were arranged as split plot with three replicates. Tree and grasses were initially harvested three months after planning of grass. Subsequently grasses were harvested at 4 week intervals at 10 cm height while trees were harvested at 12 week intervals. During the experimental period from February 2005 to Nov 2005, 12 harvests for grasses and 3 harvests for tree were done accordingly. Annual dry matter yield of grass (20.38 ton / ha/ year) grown with C calothyrsus was higher (P<0:05) as compared with the grass grown in monoculture (14.71 ton / ha/year). Similarly, total dry matter yield was also higher (P<0.05) in the mixed sward (37.68 ton/ ha/ year) as compared with pure Calliandra (23.26 ton / ha/ year) and grass swards. The land equivalent ratio (LER) was varied from 1.35 to 1.52 during a growing season in mixed sward. Relative yield total (RYT) for grass and legume was recorded as 1.35. Nitrogen percentage and nitrogen yield of grass increased with the legume. Total nitrogen yield was highest in mix culture (1.05 ton / ha/ year) and lowest with pure grass (0.54 ton / ha/ year). Further nitrogen percentage was higher (P<0.05) in grass (2.188 % ± 0.08) growing with legume contrast to grass alone (1.75 % ± 0.15) at the end of the year. (The ratio of edible and non-edible portions of the legume was 1.37). Organic matter content (1.74 %) and nitrogen concentration (0.121 %) in the soil increased in mixed culture as compared with pure culture at the end of the year. Although, Guinea A is considered as a wild type of P. maximum, the results of this study revealed that, better performances in terms of quality (Nitrogen yield) could be obtained when grown in association with Calliandra . Introduction of Guinea A with legumes might not only improve feed supply for livestock and save labour, but also be used for controlling erosion and improving soil fertility.
