Effect of oversowing leguminous species on dry matter yield and chemical composition of rangelands in Shinyanga region, Tanzania

Abstract

A study was carried out to investigate the effect of oversowing legumes on rangeland performance in Shinyanga region, Tanzania. Four leguminous species namely Centrosema pubescence, Clitoria ternatea, Macroptilium atropurpureum and Stylosanthes hamata were oversown in a natural rangeland in a complete randomised design with control plots. Seven years after oversowing, forage dry matter yield and chemical composition were estimated both in the dryand wet seasons.  Mean values of forage dry matter yieid in the dry season were 1.75, 1.69, 1.62, 1.51 and, 0.94 t/ha for the plots oversown, with, S. hamata, M atropurpureum, C. ternatea and C. pubescence and the control plots, respectively. During the wet season the yields were 1.79, 1.70, 1.66, 1.62 and 1.25 t/ha. The CP contents of the forages during the dry season were 44.4, 37.6, 36.5, 35.0 and 29.7 g/kg DM for C. ternatea, S. hamata, M atropurpureum , C. pubescence and the control plots, respectively. The CP content of the forage from plots oversown with C. ternatea and M atropurpureum  during the wet season were 68.8 and 65.6g/kg DM, respectively and were significantly (P< O. 05) higher than those oversown with S. hamata, which had CP content of 59.7 g/kg DM During the wet season the forages from oversown plots had significantly (P<0.05) higher CP values than those afthe control plots. During the dry season the control jJlotforages had significanily (P<0.05) higher NDF content (751.2 g/kg DM) and C. pubescence oversown plots had the lowest value (733.3 g/kg DM). During the wet season the NDF content ranged from 658.8 to 703.5 g/kg DM for plots oversown with M atropurpureum and the control, respectively. The ADF content of the wet season forages were 52.2, 52.0, 51.1, 50.0, and 50.7 g/kg DM for plots oversown with C. pubescence, S. hamata, M atropurpureum, C. ternatea and the, control, respectively. During the dry season the ADF content ranged from 54.3 g/kg DM for plots with C. ternatea to. 98.4 g/kg DM for those with M  atropupureum. ADL content ranged from 47.6 to 49.6 g/kg DM and from 48.9 to 66.4 g/kg DM for the wet and dry season forages, respectively. Forages from the control plots and those oversown with C. ternatea had significantly. (P < 0.05) higher ADL content than the other treatments during the dry season. It was concluded that oversowing of natural rangelands with leguminous species improves both the dry matter yield and the nutritional status of the forages.

Keywords: oversowing, rangelands, pasture yield, chemical composition

Tanzania J.Agric.Sc.(2005) Vol.6 No.2, 62-70