Abstract:

The potential for incorporating forage legumes in intensive smallholder crop/livestock farming systems was assessed in a study conducted in Masaka district, Uganda from 2002-2004. The first part of the study consisted of a diagnostic survey to characterize the production system and together with farmers identify appropriate technologies to improve feed production and animal productivity. This was followed by (i) a trial to evaluate the effects of intercropping lablab with maize or forage legumes (Centrosema pubescens, Macroptilium atropurpureun and Desmodium introtum) with elephant grass (Pennisetum purpureum) on grain yield and fodder production, (ii) a feeding trial to determine the response and profitability of lactating crossbred cows fed forages from an intercrop of maize or elephant grass with forage legumes supplemented with legume hay and a homemade concentrate and (iii) a participatory technology evaluation survey to assess the benefits and constraints from improved forage technologies to the production system. The feeding trial, consisted of 4 dietary treatments in which a homemade concentrate (HMC) was supplemented to the basal diets of: elephant grass/legume fodder (EGL) and lablab hay (LH) [Treatment 1]; EGL + LH + calliandra leaf hay (CLH) [Treatment 2]; and elephant grass fodder fed together with maize/lablab stover (EGML) + CLH [Treatment 3], A fourth treatment was elephant grass fodder served as a control [Treatment 4], Diagnostic survey showed that about 70% of the respondents were women. Age at first calving, calving interval and lactation length averaged 26, 15 and 8 months, respectively. Elephant grass was the predominant fodder grass planted by over 98 % of the respondents while legumes (herbaceous and fodder trees) were used by less than 10%. Elephant grass fodder occupied less than 35% of the total farm area. Estimated fodder DM yields were 4,171; 4,945 and 5,722 kg/ha/yr in urban, peri-urban and rural areas, respectively There was a marked decline of about 53% in total DM intake during the dry season with resultant protein and energy deficits estimated at 940 g/cow/day and 35.5 MJ/cow/day, respectively compared to a deficit of 190 g/cow/day and a surplus of 35.0 MJ/cow/day, respectively in the wet season. This resulted in a decline in milk yield during the dry season of about 44 percent. Land shortage, high cost of seed and field maintenance, were major reasons for not planting leguminous forages. Based on total scores of the diagnostic survey and results from previous on-station trials, elephant grass/legume mixtures, maize/lablab intercrop, lablab hay and calliandra leaf hay technologies were selected for on-farm trials/demonstrations to improve feed availability and overall animal productivity. Intercropping elephant grass with forage legumes (EGL) increased (p<0.05) elephant grass plant growth (79 cm) and total fodder DM yields (12,211 kg/ha/yr) by 12 and 22 percent, respectively when compared to the monocrops. Legumes contributed about 12% of total DM yield. Mean fodder DM yield of 6,488 kg/ha/yr observed in EGL during the wet season was 13% higher (p<0.05) than the DM yield observed during the dry season (5,722 kg/ha/yr). The results showed no differences (p>0.05) in mean DM yields of legumes during the dry and wet seasons (677 and 780 kg/ha, respectively). Elephant grass/legume intercropping significantly (p<0.05) increased CP and CP yield (CPY); In vitro organic matter digestibility (IVOMD) and Ca content but lowered (p>0.05) the NDF content of elephant grass fodder. The contribution of forage legumes to total CPY was 26%. Total CPY of the intercrops was higher (p<0.05) during the wet season than during the dry season. Fodder DM, grain yields, and cob size were increased (p<0.05) by 26, 7 and 6%, respectively when maize was intercropped with lablab compared to monocrops (4,373 kg/ha/yr; 2,912 kg/ha/yr; 134 g respectively). Total fodder and grain yields in ML (5,165 kg/ha) decreased by about 11 and 8%, respectively in the second rains when compared with yields during the first rains (5,806 kg/ha). On average, the CP content of ML (8.4%) was 1.9 times higher (p>0.05) in intercrops when compared to the monocrops (4.0% CP). Maize/lablab intercropping reduced (p<0.05) OM, DM and NDF but increased (p<0.05) P; Ca; IVOMD and ME compared to maize monocrop. The study showed that the quantity and quality of elephant grass fodder produced from 0.405 ha, recommended to farmers by projects that supplied the animals, was not sufficient to supply about 4,941 kg DM and 4,392 kg CP required for a mature lactating cow of about 450 kg liveweight for a full year. The minimum acreage required per mature cow was estimated to be i) 0.9 ha of EGL, ii) 0.405 ha of EGL plus 0.4 ha/year of ML or iii) 0.405 ha of pure stand of EG plus 0.4 ha/year of ML.