Reproductive Performance of Crossbred Dairy Cows in Different Production Systems in the Central Highlands of Ethiopia

The study was conducted to examine the fertility status of crossbred dairy cows in mixed crop-livestock production (MCLP), market-oriented specialized dairy production (MSDP) and urban dairy production (UDP) systems, including the Holetta Agricultural Research Center (HARC). Data on general farm management variables and reproductive histories were collected from study farms by questionnaire and from individual cow records. Age at first service and age at first calving were 29.58 months (n = 424) and 40.6 months (n = 348), respectively. Cows managed under UDP were younger at first service and at first calving (p<0.05). The mean intervals from calving to first service and to conception were 141.98 days (n = 284) and 185.02 days (n = 219), respectively. The mean calving interval for cows was 551.82 days (n = 258). Cows in MCLP had longer intervals from calving to first service and to conception and longer calving intervals than those managed under MSDP, UDP and HARC. First service conception rate (43.42%), number of services per conception (1.75) and pregnancy rate (79.29%) did not differ significantly between production systems. Reproductive performance was best in UDP followed by HARC and MSDP. The difference between MCLP and the rest points to particular difficulties in that system. To improve reproductive performance and economic benefit, there should be conservative stocking rate, sensible year-round feeding, a herd health plan, and sustainable extension service.     

An evaluation of the Acacia albida-based agroforestry practices in the Hararghe highlands of Eastern Ethiopia

Growing Acacia albida as a permanent tree crop, on farmlands with cereals, vegetables and coffee underneath or in between, is an indigenous agroforestry system in the Hararghe highlands of Eastern Ethiopia. However, there is practically no systematic record or data on the merits and benefits of this practice.The paper presents the results of an investigation into the effects of the presence of A. albida on farmlands on the yield of maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench). Twenty seven plot pairs each consisting of one plot underneath the A. albida foliage cover and the other in the open, away from the tree-on farmers' fields, in a 40 km radius around the Alemaya College of Agriculture, were sampled and the yield components analyzed. A statistically significant increase in crops yields by 56% on average was found for the crops under the tree canopies compared to those away from the trees. This increase was caused by the improvement in 1000 grain weight and number of grains of plants under the tree, indicating that the trees enhanced the fertility status of the soil and improved its physical conditions in terms of crop growth.Additional benefits from the A. albida trees include supply of fuelwood and fodder. Quantitative estimates of these outputs as well as their monetary values are presented in the paper. However, in order to realize these benefits to a discernible extent, higher stand densities of the tree than at present are required.Based on an enquiry about the farmers attitude towards A. albida, the prospects for an extension of this promising agroforestry technique are discussed against the background of the state and trends of development of agriculture in the area. It is surmised that despite some shortcomings like the relatively slow and highly variable growth of A. albida and a conflict with the spreading cultivation of Ch'at (Catha edulis Forsk.), the prospects of extension of this technique are good. It is recommended that its propagation should be incorporated into the programmes of the extension agencies of the various governmental agencies concerned with land use.     

An evaluation of Colwell‐P as a measure of plant‐available phosphorus in soils of volcanic and non‐volcanic origins in the highlands of Papua New Guinea

Various soil test methods including Olsen, Colwell, Bray and Truog have been used to assess the levels of plant‐available P (PAP) in soils situated in the highlands of Papua New Guinea (PNG). Up until now, though, there has been no guarantee that these tests provide valid assessments of PAP in these somewhat atypical organic matter‐rich tropical soils. Furthermore, the critical soil‐P concentrations associated with the tests have been based on studies conducted elsewhere in sub‐tropical and temperate latitudes and as such may or may not be valid for soils or cropping situations in PNG. Soil (Colwell)‐P and leaf‐P data collected during a recent survey of sweet potato gardens in the highlands of PNG were therefore used to determine if useful relationships existed between these variables for different groups of soils, and if they do, to use these relationships to evaluate critical soil Colwell‐P concentrations corresponding to a known critical concentration of P in sweet potato index leaf tissue. Separate, highly significant linear relationships were obtained between leaf‐P and Colwell‐P for soils of volcanic and non‐volcanic origins. Based on these relationships, the critical Colwell‐P concentration for volcanic soils was found to be four times greater than that for non‐volcanic soils, presumably because much of the P extracted from the former soils with alkaline sodium bicarbonate had been chemically ‘fixed’ via sorption and precipitation reactions with sesquioxides and rendered unavailable to plants at ambient soil pH. These critical Colwell‐P concentrations if adopted as benchmark values for the soil groups in question should ensure that the results of future soil fertility surveys involving Colwell‐P assessments are correctly interpreted.     

Policy and institutional support for agroforestry: an analysis of two Ecuadorian case studies

Institutional and policy issues are now recognized as high priority items in agroforestry research. However, such studies based on actual field experiences seldom seem to have been undertaken. To help address this deficiency, a study was undertaken in Ecuador to evaluate institutional and policy impacts on agroforestry dissemination using two field projects as case studies.The projects were in contrasting ecological locations: the Amazonian lowlands (the Coca Agroforestry Project), and the Andean highlands (the PROMUSTA project). The impact of policy and institutional constraints (such as land tenure, research and extension support, marketing and pricing, and credit) on the implementation of these projects was assessed based on interviews with farmers and project officials as well as analyses of secondary data. The Coca project was found to be adversely impacted by the lack of extension, product marketing, and credit availability. The principal institutional constraints for the Andean project included legal obstacles to farm-land procurement, inadequate extension, little state-financial assistance, and limited affordable credit. The relevance of these issues was location specific: while access to land was not a serious constraint in the lowlands, it was a major issue in the highlands.The study validates the premise that policy and institutional evaluations should become an essential component of design and implementation of agroforestry projects. Although the components of a sound policy framework might be similar in most developing-country situations, it may not be possible to evolve universally applicable procedures for agroforestry-policy formulation because of the location-specificity of the promoted systems and the institutional issue related to their adoption.Florida Agricultural Experiment Station Journal Series No. R-03861.     

Shifting cultivation systems practised in Bhutan

In the highlands of Bhutan shifting cultivation remains an important land use practice, covering an area of approximately 200,000 ha. Two systems, bush fallow and grass fallow, are described and discussed. The traditional methods used in the two systems are well adapted to available resources. The systems differ in fallow vegetation, altitude range, major crops, fallow period, farming tools, clearing method, labour inputs, and erosion risks. Soils used for the grass fallow system are low in P and N. Major limitations for the bush fallow system are weed competition and the steep terrain. Returns from labour wereapproximately 10.6 and 4.2 kg grain per day for the bush fallow and the grass fallow system, respectively. Access to market through a recently built road system provides some cultivators with lucrative alternatives in the form of timber, livestock and potato production. Alternative options are more limited in the bush fallow system.This work was supported by the Department of Agriculture, Royal Government of Bhutan and the Swiss Association for Technical Assistance     

Wheat growth as influenced by application of agroforestry-tree prunings in Ethiopian highlands

The response of wheat (Triticum aestivum cv. Enkoy) to application of leaf prunings of nine agroforestry-tree species was investigated in a field trial and a six-week pot trial. The tree species were Grevillea robusta, Erythrina abyssinica, Gliricidia sepium, Albizia schimperiana, Acacia nilotica, Acacia polyacantha, Leucaena leucocephala, Leucaena pallida and Entada abyssinica. L. leucocephala, L. pallida, G. sepium and Entada abyssinica proved to be good pruning sources in the pot trial. G. robusta, A. polyacantha, A. nilotica and E. abyssinica had adverse effects on wheat seedlings with increased pruning loads probably due to immobilization processes or allelopathic effects. N and lignin content, C/N ratio, lignin/N ratio, phenolics/N ratio and (phenolics + lignin)/N ratio of the pruning material were all significantly correlated with shoot dry matter production of the wheat seedlings. With the exception of Entada abyssinica, which performed well under field conditions, a similar ranking as in the pot trial was established in the field experiment, but at harvest differences were not as pronounced as in the pot trial. Gliricidia treated wheat produced by far the highest grain yield with 248 g/m².This revised version was published online in November 2005 with corrections to the Cover Date.     

Land Use and Cover Dynamics Since 1964 in the Afro‐Alpine Vegetation Belt: Lib Amba Mountain in North Ethiopia

Human‐induced land use and land cover (LUC) changes threaten the ecosystem services of the vulnerable tropical afro‐alpine vegetation. Several LUC change studies are available for the Ethiopian highlands, but relatively little is known about LUC change in the afro‐alpine zones. In this study, LUC changes between 1964 and 2012 were mapped for the afro‐alpine zone of Lib Amba Mountain, part of the Abune Yosef Mountains in North Ethiopia. Historical LUC was derived from georeferenced aerial photographs of 1964 and 1982, and the present LUC (2012) from Bing Map satellite imagery. Based on these successive LUC maps a time‐depth map, LUC proportions, LUC transition matrices and LUC change trajectories were calculated. Two main phases of LUC change could be distinguished linked to the neo‐Boserupian perspective. (i) Between 1964 and 1982, there were large‐scale deforestation and general degradation of the vegetation above 3500 m, in a period of low population pressure; (ii) Between 1982 and 2012, an intensification of land use prevailed accompanied with a slight regeneration of the vegetation and the Erica arborea L. forest, under increased population pressure. Depth interviews indicated that local and governmental land management measures are very important for the protection against vegetation depletion and soil degradation. Quick recovery of the forest on Lib Amba provides confidence that degraded afro‐alpine areas would benefit in a short time from complete protection, given the vicinity of remaining patches of afro‐alpine vegetation. Management interventions are thus vital to restore the important ecosystem services of the afro‐alpine vegetation belt. Copyright © 2015 John Wiley & Sons, Ltd.     

Economic Contribution of Draught Animals to <Emphasis Type="Italic">Mazahua</Emphasis> Smallholder <Emphasis Type="Italic">Campesino</Emphasis> Farming Systems in the Highlands of Central Mexico

The economic contribution of draught animals to smallholder Mazahua campesino systems in two mountain villages of San Felipe del Progreso, in the central highlands of Mexico, was assessed. Campesinos rely on draught animals for cultivation tasks, as pack animals, and as transport for agricultural and domestic activities. The villages were San Pablo Tlalchichilpa (SPT) and La Concepción Mayorazgo (LCM). Twelve households that possessed draught animals were monitored from July 1999 to June 2000, nine in SPT and three in LCM, in terms of animal inventories and income from their draught animals, in cash and opportunity values. Equines in SPT have substituted bulls, and are recognized for their multipurpose contribution, while in LCM bulls are still used for ploughing the land. Overall total mean gross income was US$490.78 per farm per year, plus US$56 as opportunity value of the fertilizer value of manure for both villages. Deducting estimated costs, owning draught animals leaves a mean net margin of US$412.50/year in SPT and of US$285.64/year in LCM. There is a significant correlation (p < 0.05) between ownership of draught animals and incomes, with a regression coefficient of US$279.16 per year per draught animal. Besides positive economic returns, having work animals alleviates drudgery for the campesino families.     

Soil and water conservation in Tigray (Northern Ethiopia): the traditional dagat technique and its integration with introduced techniques

Between the cultivated fields in the highlands of Tigray, one finds, besides the recently introduced stone bunds, many lynchets, with a height ranging from 0·3–3 m. Grasses occupy the riser and a more or less large strip on the shoulder. Traditionally, farmers established an untilled strip of about 2 m wide at the lower plot limit. This grass strip reduced runoff velocity, allowed for water to infiltrate and trapped sediment. Year after year, these lynchets, locally called dagat, continued to grow. In this study, the dagat technique is characterized and its evolution and reasons for partial destruction are outlined. Stereoscopic aerial photo analysis shows for the study area near Hagere Selam (13 °39′N, 39 °10′E, 2650 m a.s.l.) that 20·7 per cent of the major dagats (more than 1 metre high) have disappeared between 1974 and 1994. These lynchets, however, remain an important linear element in the landscape (22·7 m ha⁻¹, i.e. their density on cultivated fields is much higher). Of the smaller lynchets, a great proportion has been levelled in order to increase plot surfaces and spread fertile soil over the field. Famines and impoverishment caused the farmers to increase short‐term agricultural production in this way. Since the 1980s, the farmers built stone bunds on most of the cultivated land. Their average length equals 56·1 m ha⁻¹ in the study area. The establishment of stone bunds results in the development of small terraces. Especially during recent years, there is a tendency to integrate the traditional knowledge of dagat with the building of stone bunds. A quantitative assessment of the effectiveness of both techniques must be made. Copyright © 2000 John Wiley & Sons, Ltd.     

Rodent abundance,stone bund density and its effects on crop damage in the Tigray highlands,Ethiopia

In areas of subsistence agriculture, a variety of soil conservation methods have been implemented in the last few decades to improve crop yields, however these can have unintended consequences such as providing habitat for rodent pests. We studied rodent population dynamics and estimated crop damage in high and low stone bund density fields for four cropping seasons in Tigray highlands, northern Ethiopia. Stone bunds are physical structures for soil and water conservation, and potentially habitat for rodents. We used a general model to relate the proportion of crop damage to rodent abundance, stone bund density and crop stages. Generally, rodent abundance remained relatively low during the study period, except during the fourth quarter of the 2010 cropping season. We found a positive correlation between rodent abundance and crop damage, and significant variation in rodent abundance and crop damage between high and low stone bund density fields. Furthermore, crop damage also varied significantly between crop stages. We concluded that Mastomys awashensis (Lavrenchenko, Likhnova and Baskevich, 1998) and Arvicanthis dembeensis (Ruppel, 1842) were the two most important crop pests in Tigray highlands causing significant damage. Fields with high stone bund density (∼10 m average distance apart) harbor more rodents and endure a significantly higher proportion of crop damage compared to fields with lower stone bund density (∼15 m average distance apart). The fact that rodent abundances peaked during the reproductive stage of the crop and around harvest implies the need for management intervention before these crop stages are attained.