M. A. Mohamed Saleem

Hydrologic response to cattle grazing in the Ethiopian highlands

Abstract The effect of grazing pressure on infiltration, runoff, and soil loss was studied on a natural pasture during the 1995 rainy season in the Ethiopian highlands. The study was conducted on 0.01 ha plots established on sites with 0–4% and 4–8% slopes at the International Livestock Research Institute (ILRI) Debre Zeit research station, 50 km south of Addis Ababa. The grazing regimes were: light grazing stocked at 0.6 animal-unit-months (AUM) ha −1 ; moderate grazing stocked at 1.8 AUM ha −1 ; heavy grazing stocked at 3.0 AUM ha −1 ; very heavy grazing stocked at 4.2 AUM ha −1 ; very heavy grazing on ploughed soil stocked at 4.2 AUM ha −1 ; and a control with no grazing. Heavy to very heavy grazing pressure significantly increased surface runoff and soil loss and reduced infiltrability of the soil. It was observed that fine textured soils were more susceptible to trampling effects than coarse textured soils, and that reduction in infiltration rates was greater on soils which had been tilled and exposed to very heavy trampling. The problems of high runoff and erosion rates on the upper slopes is likely to be exacerbated by the fact that during the rainy season higher grazing pressure is exerted on the upper than lower slopes. Sediments produced from the highlands, which form headwaters of major rivers in the region, are likely to pollute streams and lakes and pile up on bottom-lands, in stream channels, and in reservoirs. With some modifications, the plot design presented here can be used for assessing livestock impacts on natural resources on different landforms at large scales such as watersheds. How the same amount of livestock mass dispersed by different livestock species impacts on the grazing lands needs to be studied further.

Vegetation response to cattle grazing in the Ethiopian highlands

Abstract The effect of grazing cattle on vegetation was studied on a natural pasture during the rainy and dry seasons of 1995 in the Ethiopian highlands. The study used 0.01 ha plots, established on 0–4% and 4–8% slopes located close to each other at Debre Zeit research station, 50 km South of Addis Ababa. The grazing regimes were: light grazing stocked at 0.6 animal-unit-month per hectare (AUM ha−1); moderate grazing stocked at 1.8 AUM ha−1; heavy grazing stocked at 3.0 AUM ha−1; very heavy grazing stocked at 4.2 AUM ha−1; very heavy grazing on ploughed pasture stocked at 4.2 AUM ha−1; and a control of ‘no grazing’. Heavy grazing significantly reduced vegetative cover and biomass yields, especially on steeper slopes. Light to heavy grazing did not affect the botanical composition of the vegetation at both sites, but very heavy grazing resulted in species normally less preferred by animals dominating the botanical composition. Grazing did not have significant effect on ground vegetative cover on the 0–4% slope except at very heavy grazing pressure, but on the 4–8% slope even moderate grazing significantly reduced vegetative cover. Light to moderate grazing at the beginning of the dry period enhanced plant biomass productivity, while any grazing reduced plant productivity during the periods of reduced growth. Species richness increased with increasing grazing pressure compared with no grazing, but decreased sharply at very heavy grazing pressure. We concluded that there is need for developing ‘slope and time specific’ grazing management practices, and to assess short and long term effects of grazing and trampling on vegetation.

Nutrient balance patterns in African livestock systems

Abstract This paper presents an overview of the current status, problems and prospects for achieving a better nutrient balance to support varying levels of productivity from the three major livestock systems in Africa. In free range grazing systems, livestock nutrient deficiencies are mainly overcome by moving the animals to better grazing areas. This makes monitoring and managing of nutrients within a system very difficult. Nutrient recovery, cycling and synchronization of manure with other recycled or purchased sources are greater in mixed crop–livestock systems. In these systems, inclusion of nitrogen-fixing leguminous forage/tree crops as companions or rotation crops with cereals further improves the nutrient use efficiency and balance. With more favourable market and policies, commercialized dairy systems are developing around the urban areas of Africa. Such systems heavily depend on purchased feeds and nutrients, and have serious implications for the nutrient balance and sustainability of land use systems in the rural areas which supply the feeds, and for the urban areas because of the risk of pollution from the accumulating animal wastes.

Soil water dynamics under cereal and forage legume mixtures on drained Vertisols in the Ethiopian highlands

Abstract At the Debre Zeit Station cereals (wheat and maize) and forage legumes (lablab, cowpea, vetch and clover) were grown as sole crops and as cereal/forage combinations on the broadbeds separated by drainage furrows (BBF). This is an improved land management system, developed by ILCA in collaboration with other national and international partners, to raise productivity of Vertisols. Soil water content monitored at soil depths of 0–50 cm and 50–100 cm indicated that lablab and cowpea deplete significantly greater amounts of available soil water during the growing season than vetch and clover. Deep rooted forage legumes lablab, cowpea and vetch are more suitable for combination with cereals such as maize than with wheat due to the phenological differences between the two crop types. Grain yields of wheat and maize were higher when intercropped with legumes than as sole crops in the absence of external N input. Moisture use by the various crop-forage land use types are discussed.

TECHNICAL AND ECONOMIC PERFORMANCE OF ANIMAL-DRAWN IMPLEMENTS FOR MINIMUM TILLAGE: EXPERIENCE ON VERTISOLS IN ETHIOPIA

SUMMARY Land degradation is one of the major problems related to low productivity in Ethiopia. Vertisols are potential agricultural lands but are underutilized due to water-logging during the rainy season and are prone to soil erosion due to the traditional practices of planting crops at the end of the rainy season exposing bare land to heavy rains. An animal-drawn implement, the broad-bed maker (BBM), was tested to facilitate drainage of the vertisols. Improved drainage enables earlier planting of crops to use the resultant prolonged growing period for attaining higher yields. In order to further improve the BBM package, the frame of the BBM was used for attachment of other implements to minimize tillage practices and reduce seed and fertilizer rates, labour and animal power requirements and soil erosion. The attachments were tested both on-station and on-farm with positive results. INTRODUCTION In most crop-livestock mixed farming systems in developing countries, different kinds of animal-drawn simple and mould-board ploughs are used for tillage. The number of cultivations or passes needed to achieve a good tilth depends on soil type, moisture level, crop to be grown and adequacy of draught animals. On some kinds of soils extensive tillage damages soil structure and contributes to soil erosion. Zero-and minimum-tillage practices are often recommended to avoid such problems. In Ethiopia, 90% of land preparation for crop production by smallholder farmers is done with the traditional ‘maresha’ plough pulled by a pair of local zebu oxen. Three to five cultivation passes, each pass perpendicular to the previous one, with the maresha are required for all types of soils before a field is ready for planting. The first pass reaches a soil depth of 8 cm while with the last pass up to 20 cm depth can be attained (Astatke and Ferew, 1993). Land is usually prepared before the main rainy season and some crops, for example the principal cereal tef (

Options to intensify cropland use for alleviating smallholder energy and protein deficiencies in the East African Highlands.

Abstract Land-use intensification in the east-African highland zone is required for meeting food and feed demands from the rising human and animal populations. A single crop of wheat has been a traditional practice for the 8 Mha of vertisols in the Ethiopian highlands with both grain and residues finding use. With proper drainage, early sowing of crops becomes feasible, and this study compared the local wheat system with eight other land-use types (LUTs). Replacing local wheat with genetically superior wheat, cv. ET 13, significantly increased grain and fodder and also the metabolizable energy from a land unit. When ET 13 was followed by grasspea, and intercropped with clover and/or sown between sesbania alleys, the feed, protein and energy outputs from the same land unit were further enhanced many fold compared to the traditional landuse. By combining crops and forages with different maturity and harvest times, it was also possible to change feed availability patterns during the year. How these different options could be targeted to serve multiple crop/livestock objectives of the smallholder is discussed briefly.

Effect of different cropping options on plant-available water of surface-drained vertisols in the Ethiopian highlands

The productivity of the Vertisols in the Ethiopian highlands could be raised by facilitating the removal of excess water from the fields in the main rainy season. This could be accomplished by the introduction of an animal powered broadbed maker (BBM) which shapes the soil into broadbeds and furrows. Thus with proper drainage, early sowing of crops becomes feasible. This study compared the plant-available water in the soil layer and the water use efficiency of local wheat and eight other cropping options and also assessed the grain and fodder productivities. Replacing late-sown local wheat with an early-sown improved wheat variety (ET-13) improved the utilization of the plant-available water during the rainy season and significantly increased grain and straw yields with a high rate of water use efficiency. The variations of the available moisture in the soil layer between the different cropping options tested were small during the rainy months of July and August due to the continuing replenishment of the used water. Differences of plant-available water in both upper and lower soil layers for the various cropping options became distinct at the onset of the dry season. Even though results showed that growing of a sequential crop, such as grass pea, following wheat is possible with a starter irrigation in the dry season, yields were generally depressed.

Role of knowledge in the adoption of new agricultural technologies: an approach and an application

Empirical studies on agricultural technology adoption generally divide a population into adopters and nonadopters, and analyse the reasons for adoption or nonadoption at a point in time. In reality, technology adoption is not a one-off static decision, rather it involves a dynamic process in which information gathering, learning and experience play pivotal roles, particularly in the early stage of adoption. A conceptual framework for an adoption pathway is suggested in which farmers move from learning to adoption, to continuous or discontinuous use over time. The framework was applied to understand the adoption pathways for vertisol management technology in highland Ethiopia. Analysis of a sample of 585 households confirmed that a simple classification of farmers as adopters and nonadopters was inadequate to understand the adoption process. Rather, a multistage decision process in which farmers moved from learning to adoption to continuous or discontinuous use was more appropriate. The sets of factors that significantly influenced decisions to acquire knowledge about BBM, to adopt and then to use it continuously or discontinuously were different. The lag between learning and adoption, and the possibility of discontinuation and readoption, imply that a longer period will require for majority of the farmers to use the technology than if adoption was a one off decision leading to continuous use.

Towards Transdisciplinarity in Technology and Resource Management Research: A Project in Ethiopia

The paper first discusses the need for moving from disciplinary to transdisciplinary research in addressing problems of human development and environmental management. Then the experience of a research project in highland Ethiopia is described. This started with disciplinary research and component technologies to address problems of poverty, malnutrition, low agricultural productivity and resource degradation, and gradually moved towards integrated resource management and a transdisciplinary approach. Although a systems approach was adopted to diagnose problems, discipline-based component technology research was initially a dominant characteristic of the project. Individual technologies were designed and tested on-farm with farmer participation — often separately, and their impacts were assessed mostly in bioeconomic terms, eg for yield and income. Gradually the need for simultaneously assessing the economic, social and environmental effects of several technology interventions at plot, household and watershed/community levels was recognized. The research methods have been modified accordingly to adopt an integrated and holistic approach incorporating biophysical, economic and social dimensions of the ecosystem. An agroecosystem health approach to ecosystem analysis is currently being used as an integrative analytical framework. This evolution has also meant a gradual shift from a disciplinary to a multidisciplinary, and finally to a transdisciplinary approach to research.

Tillage methods for the cropping of sorghum in legume fodder banks in the subhumid zone of Nigeria

Abstract Various methods of growing sorghum in stylo fodder banks were studied, with the intention of optimizing grain and fodder yields. Methods included ridging vs. flat seedbed preparation, transplanting vs. seeding, and suppressing or encouraging the growth of the forage legume during food crop growth. Planting on ridges gave 60% higher grain yields than planting on the flat. Yields were also 67% higher compared to direct seeding when sorghum was transplanted. On average, transplanting sorghum on ridges in fodder banks produced 1487 and 5230 kg/ha of grain and fodder, respectively, as compared to the corresponding yields of 1037 and 4946 kg/ha when planted outside the fodder bank. The use of herbicide reduced the legume content by 50% in the total fodder from a fodder bank and thus its nutritive value. As the cropping techniques tested do not deviate substantially from the existing traditional practices, no special cultivation methods are required to crop a land sown with stylo. This could facilitate adoption of short crop-legume ley rotations in the subhumid zone.