Ben A. Lukuyu

Maize as food and feed in intensive smallholder systems: management options for improved integration in mixed farming systems of east and southern Africa

Abstract As systems intensify, crops and livestock become increasingly integrated. Forage from crops becomes a larger component of overall forage supply in small-scale systems. This paper integrates information from field trials, studying the effect of varying maize planting density, with modelling approaches to compare this with supplementation of maize stover, genetic improvement of stover digestibility and replacement of the maize crop with planted forage in east and southern Africa. Aggregate analyses for small-scale intensive (SSI) systems producing milk were carried out using a suite of models including CERES, CROPGRO, DRASTIC and ANORAC, scaling-up to regional level using GIS information. Increasing planting density increased the yield of thinnings, but decreased grain and stover yields. Model predictions of milk production from the thinnings and stover produced from one hectare of maize indicated that economic benefits to increased planting density could be achieved when the grain:milk price ratio was low, despite the negative effect on grain yield. Supplementation showed the greatest economic returns with small positive impacts on soil fertility and maize production. Replacing maize with planted forage inevitably increased milk at the expense of maize production. Again, for this intervention, grain:milk price ratios ranging from 0.19 to 2.88 across sub-Saharan Africa are likely to influence the decision of the farmer whether or not to trade milk for grain. Genetic enhancement of the digestibility of maize stover was found to have little impact on milk production because diets based on stover were deficient in nitrogen, preventing animals from benefiting from the increased energy supply resulting from digestibility increases. Other factors such as market access and stability, as well as individual objectives such as cash flow, food security and risk minimisation, were not explored in the present study but will influence household decisions. More complex analyses, accounting for these factors, may be required to predict adoption behaviour, however, the results of the study can be used to evaluate the potential returns to investment in research in the different areas using an economic surplus model.

Nutrient composition and seasonal availability of local feedstuffs for pigs in western Kenya

Carter, N. A., Dewey, C. E., Lukuyu, B., Grace, D. and de Lange, C. F. M. 2015. Nutrient composition and seasonal availability of local feedstuffs for pigs in western Kenya. Can. J. Anim. Sci. 95: 397-406. In this study, nutritional values and seasonal availability were estimated for 25 local feedstuffs for pigs in western Kenya, based on analyzed nutrient contents and a review of the literature. Characteristics considered included: crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), ether extract (EE), Ca, P, standardized total tract digestible (STTD) P, total Lys, standardized ileal digestible (SID) Lys (all as g kg-1 of DM), and digestible energy (DE) (kcal kg-1 DM). Contents of total Lys, SID lysine, STTD P, and DE were estimated. Overripe improved-variety avocado (Persea americana) had the greatest estimated DE (5280 kcal kg-1 DM) and EE content (521 g kg-1 of DM). Cattle rumen content had the greatest NDF content (664 g kg-1 of DM). Sun-dried fish (Rastrineobola argentea) had the greatest estimated STTD P content (13.5 g kg-1 of DM). Amaranthus spinosus L. had the greatest Ca content (26 g kg-1 of DM). Fresh cattle blood had the greatest CP and estimated SID Lys content (944 and 83.0 g kg-1 of DM, respectively). Feedstuffs availability periods are: March through May plus September and October; June through August; and November through February. Local feedstuffs of sufficient nutritional value for pigs are seasonally available. Estimated nutritional values may assist in diet formulation.

Nutritional Value and Seasonal Availability of Feed Ingredients for Pigs in Uganda

Abstract In this study nutritional values and seasonal availability of 43 local feed ingredients for pigs in Uganda, were estimated based on nutrient analyses and literature values, information needed to develop low-cost balanced rations for pigs on smallholder farms. Parameters considered were: concentration of ash, neutral detergent fibre (NDF), crude protein (CP), calcium (Ca), phosphorous (P), ether extract (EE), total lysine (Lys), standardized ileal digestible (SID) Lys, standardized total tract digestible (STTD) P (all as % of dry matter [DM]); digestible energy (DE), (kcal kg−1 of DM); and DM concentration. Concentration of DE, total Lys, SID Lys, and STTD P were estimated. Ingredient seasonal availability and relative importance were identified. Ground sun-dried fish (Rastrineobola argentea) had highest estimated DE concentration and Napier grass (Pennisetum purpureum) had lowest (4209 and 535 kcal kg−1 of DM, respectively). Ground sun-dried fish had highest CP and estimated total Lys concentration (59.9 and 6.7% of DM, respectively) and banana peel (Musa sapientum), had lowest (5.21 and 0.08% of DM, respectively). Milled ingredients sampled here had higher ash than in the literature (e.g. ground sun-dried fish 58.1 vs 15.9% of DM) likely indicating sand contamination. There were 3 seasons of availability of ingredients. Banana peel, maize bran, and sweet potato vine (Ipomoea batatas) were ranked highest; and commercially-prepared ration, and kale/collard greens (Brassica oleracea var. acephala), were ranked lowest as potential feed ingredients. Ingredients with nutritional profiles suitable for pigs are available but some only in certain seasons. Estimated nutritional values may assist in ration formulation.

Agroforestry: Fodder Trees

Fodder trees are important feed sources for livestock in a wide range of agroforestry systems throughout the world. Farmers have used fodder trees since ancient times and they are common in traditional feeding systems. In recent times there have been significant movements of germplasm and increased cultivation of fodder shrubs in many areas. Fodder trees are easy to grow, require little land, labor or capital, have numerous by-products and often supply feed within a year after planting. Key challenges constraining the uptake of fodder trees include limited species appropriate to different agroecological zones, shortages of seed and that many farmers lack knowledge and skills needed to grow them.

Evaluation of Sweetpotato Varieties for the Potential of Dual-Purpose in Different Agroecological Zones of Kenya

Smallholder dairy farming is important in Kenya, however reducing farms into subdivisions over the past four decades has resulted in small farms. Meeting the nutritional requirements of high yielding dairy cows is now a constant challenge to the farmers especially during the dry season. Sweetpotato is a potential source of food and feed for smallholder farmers. The high biomass yield and quality of sweetpotato storage roots and vines are two of the most important factors that deserve attention when it is used as a feed. The present study evaluated six cultivars of sweetpotato for their potential as dual-purpose crops, biomass yield, and quality in different agroecological zones in Kenya. Six cultivars of sweetpotato were grown on farms in five sites located in the Central, South, and North Rift Valley regions of Kenya under rain-fed conditions. Two sites each were located in the high and medium altitude area while one was located in the low altitude area. All sites have a warm climate except the one at high altitude that experiences a cold climate. The cultivars were 103001, Gweri, Kemb-23, Kemb-36, Naspot-1, and Wagabolige. The vines of each variety were harvested at two different stages (75 and 150 days) post-planting. The 75-day treatment was ratooned again at 150 days post-planting. Agronomic observations were carried out during the long rainy season in 2010. Harvesting vines twice significantly (P < 001) increased forage yields but significantly reduced root yield in all the varieties. Gweri variety realized the highest forage yield but the lowest storage root yield indicating its potential as a forage variety. Kemb23, Kemb36, and Naspot1 produced appreciable amounts of vines and the highest root storage yield showing their potential as dual-purpose varieties. The effect of cultivar on forage yield varied with time of harvest. There was a high interaction between the cultivars and stage of harvest at 150 days after planting. Gweri, Kemb 23, and Kemb 36 showed some level of interaction with stage of harvesting at 150 days after planting. Across AEZs vine yields (t/DM/ha) ranged from 0.9 t/ha at high altitude (dry), 2.4 at high altitude (wet), 1.7 at low altitude (dry), and 2.8 medium altitude (wet). The root to vine ratios (R/V) obtained classifies cultivar 103001 as a low forage-high storage root cultivar while Gweri was classified as a forage cultivar in all AEZs. Four other varieties (Kemb‐23, Naspot‐1, Wagabolige, and Kemb 36) were identified as “best bet” dual-purpose varieties. Harvesting sweetpotato plants twice at 75 and 150 days post-planting increased vine yield by 34 % but also reduced tuber yields by 54 %. The practical implications of these results is that farmers in each AEZ will have at least one suitable forage, dual-purpose or root variety to choose from depending on the feed needs on farms.

The Role of Forages in Sustainable Intensification of Crop-Livestock Agro-ecosystems in the Face of Climate Change: The Case for Landscapes in Babati, Northern Tanzania

Agro-ecosystem productivity is highly dependent on soil moisture fluxes yet climate change induces unpredictable dynamic interactions on water and nutrient resources. This study assessed on-farm seasonal productivity, runoff and soil moisture storage estimates within forage grass and forage legume intercrops at the Long site in Babati District of Northern Tanzania and how these would be impacted by climate change. The WaterWorld model was used to ascertain the impact of climate change on temperature and moisture fluxes at landscape level within these agro-ecosystems. Study results revealed a steady increase in temperature and a projected increase in rainfall over the next 40 years to the 2050s with an average future precipitation of 1300 mm yr−1 compared to the current baseline of 960 mm yr−1. On-farm seasonal water balance estimates within forage grass–forage legume intercrops revealed that with the 645 mm of rainfall received in the 2014 rainy season, evapotranspiration (ET) was the predominant factor accounting for about 75 % of the fluxes. We demonstrate that compared to the control trials, runoff levels were significantly lower in areas with forage grass–legume intercrops which translated to 20 % lower runoff levels; there was higher soil moisture storage with an average of about 25 mm (30 % higher) in areas with forage grass–forage legume intercrops than the bare plot control areas. The Napier-Desmodium and Napier-Lablab combinations had about 15 % higher soil moisture storage and 30 % higher water productivity compared to the sole Napier accessions. The sole forage grasses depicted about 15–50 % higher runoff levels compared to the Napier-Desmodium and Napier-Lablab combinations. In doing so, a combination of perennial forages (grasses and legumes) improves the sustainability of farming systems through erosion control and soil moisture retention beyond serving as feed resources. Using both qualitative and quantitative metrics from this study, we draw on the sustainable intensification indicators framework to illustrate explicit linkages on synergies and tradeoffs associated with forage interventions within smallholder farming systems. Sustainable intensification within these landscapes will thus require more innovative solutions that incorporate establishing different types of alternative forage grass–forage legume combinations coupled with other improved agronomic practices into a compendium package of interventions that allows for sustainable land use to cope with climate change and variability.