Institutional Challenges in Sustainable Forest Management: Evidence from the Gambella Regional State of Western Ethiopia

This article explores the ambiguity over property rights to forest resources in the Mejengir Zone of Gambella Regional State in western Ethiopia. Household surveys and focus group discussions were used as data collection tools. Results indicate that the complexities in forest management are mainly attributable to diversity in livelihoods as well as users’ heterogeneity in perceptions and actions. Ambiguity was created both through the process of decentralization in forest management and the demarcation of regional forest priority areas without public participation. The weakness of the state in undertaking effective supervision to overcome corruption has also exacerbated this problem. A lack of well-defined property rights has resulted in deforestation and loss of biodiversity, and unclear property rights, reflecting an ineffective local forest governance structure. The resulting behavioral uncertainty among users puts pressure on forest resources, which favors the conversion of forests into other land use models. State development programs were also found to be sources of ambiguity over property rights and thereby created challenges for collective forest management. Therefore, local institutional structures should be improved to help accommodate more traditional systems of forest management and to ensure sustainability in forest management practices.     

Assessment of farmers’ perceptions of production constraints,and their trait preferences of sorghum in western Ethiopia: implications for anthracnose resistance breeding

Sorghum, Sorghum bicolor (L.) Moench is an important food security crop widely grown by smallholder farmers in sub-Saharan Africa (SSA), including Ethiopia. In SSA, the potential of sorghum production and productivity has not been realised due to an array of constraints. Colletotrichum sublineolum disease is one of the main biotic constraints causing significant yield losses. The objectives of this study were to assess farmers’ perception, preferences and constraints to sorghum production and productivity in western Ethiopia, and to identify key drivers for anthracnose resistance breeding. A participatory rural appraisal study was undertaken in six selected districts in the East Wellega and West Shewa Administrative Zones in Ethiopia. Data were collected through structured questionnaires involving 165 respondent farmers. Further focus group discussions were held with 180 farmers and development agents. Sorghum is the third most preferred cereal crop after Eragrostis tef and Zea mays in western Ethiopia. About 79% of interviewed farmers cultivated sorghum during the study season. Farmers perceived that sorghum production is constrained by anthracnose disease, bird attack, loose smut and covered smut diseases. The most important farmer-preferred traits in sorghum varieties in the study areas were anthracnose resistance and tolerance to bird attack. Breeding sorghum varieties with the farmer-preferred traits is an important consideration to enhance productivity and adoption of improved sorghum cultivars in western Ethiopia.     

Scoring system for evaluating the stress to cattle of commercial loading and unloading

The loading and unloading of cattle for road transport is stressful but the stress is difficult to evaluate in terms of the welfare of the cattle. Over one year, 40 normal commercial journeys in northern Spain were analysed in terms of time limits and behavioural events in order to design an objective method for assessing the stresses imposed on the animals, and a scoring method was developed for assessing the welfare of the animals during loading and unloading. Several definitions of time intervals were assessed to calculate a time score per animal, and easily observable behavioural events were scored and combined with the time score to obtain a total loading/unloading score. More than half of the loadings and unloadings involved turns, slips and vocalisations. Mounts and bouts of fighting were infrequent and balks and falls were significantly more frequent during loading than unloading. The plasma concentrations of cortisol, glucose and lactate, the activity of creatine kinase and the pH of the meat 24 hours after the animals were slaughtered were also measured. The results indicated that loading was more stressful than unloading and that higher scores implied significantly higher levels of stress.     

Post-mortem findings of gastric ulcers in Swedish horses up to one year of age: a retrospective study 1924-1996

Necropsy records from 702 horses, less than one year old, that were subjected to necropsy between 1924 and 1996 were used to estimate the prevalence of gastric ulceration in younger horses and to evaluate some potential risk factors that may contribute to the development of gastric ulceration. Information concerning breed, gender, age, season of death, clinical signs of colic, medical treatment, parasitism and documentation of diseases in different organs were recorded, as well as size, number and anatomical distribution of ulcers. Gastric ulcers were found in 96 of 702 young horses (14%) and gastritis in another 64 animals (9%). The cutaneous region adjacent to margo plicatus (51%), and the corpus region were commonly affected (46%). The investigation clearly demonstrates that gastric ulceration has affected young Swedish horses to a similar degree during most of the 20th century. A significant (p < or = 0.05) association between gastric ulcers and the signs of colic, parasitism and a concomitant intestinal, liver, and oesophageal involvement was found. No breed or sex predilection with gastric ulcers was obtained. The risk of gastric ulcers was highest during the fall (odds ratio 3.52) and lowest during the summer (odds ratio 0.45). The seasonal variation could not be explained by concomitant findings of Gasterophilus larvae. By using a multivariate logistic regression analysis, only season significantly influenced the risk of gastric ulceration.     

Synthesis of soybean oil-based polymeric surfactants in supercritical carbon dioxide and investigation of their surface properties

This paper reports the preparation of polymeric surfactants (HPSO) via a two-step synthetic procedure: polymerization of soybean oil (PSO) in supercritical carbon dioxide followed by hydrolysis of PSO (HPSO) with a base. HPSO was characterized and identified by using a combination of FTIR, (1)H NMR, (13)C NMR, and GPC methods. The effects of HPSO polysoaps on the surface tension of water and interfacial tension of water-hexadecane were investigated as a function of concentration of HPSO and counterion chemistry. HPSO polysoaps were effective at lowering the surface tension of water and the interfacial tension of water-hexadecane. They displayed minimum values of surface tension in the range of 20.5-39.6 dyn/cm at a concentration range of 3.2-32 μM and minimum values of interfacial tension in the range of 15.6-31.44 dyn/cm. The minimum surface and interfacial tension values were highly dependent on the nature of the counterion and increased in the order K(+) < Na(+) < TEA(+). These results suggested that a very low concentration of surfactant can be used to reduce the surface tension of water and interfacial tension of water-hexadecane. Water-hexadecane interfacial energy was also calculated from measured surface tension data using Antonoff, harmonic mean (HM), and geometric mean (GM) methods. Measured values agreed well with those calculated using the HM and GM. The HM method predicted slightly higher values than the GM method, but the Antonoff method did not agree with measured values.     

Abundance of insect pests and their effects on biomass yields of single vs. multi-species planted fallows

Indigenous and exotic leguminous shrubs that are promising for planted fallow for soil fertility replenishment in east and southern Africa have been found to harbour many herbivorous insects, giving suspicion that widespread adoption of fallow systems may aggravate insect pests. Studies were conducted on farms in western Kenya from 1999 to 2001 to monitor the abundance of herbivorous insects and assess their effects on biomass yields of pure and mixed fallows. The treatments tested were single and two-species mixtures of Tephrosia vogelii, Sesbania sesban and Crotalaria grahamiana and a natural fallow in a split plot design, with the fallow systems in the main plots and protection vs. no protection against insects in sub-plots spread over six farms. Eighteen insect species belonging to seven orders and 14 families were identified as pests of␣the fallows with varied abundance and infestation level across the sites. While Hilda patruelis and Amphicallia pactolicus were most damaging to C. grahamiana, Mesoplatys ochroptera was detrimental to S.␣sesban. T. vogelii hosted fewer insects than others. Nevertheless the pest infestation did not cause significant biomass yield reduction during the study period. Pest attack was generally greater in villages that had been testing the planted fallows for some years compared with villages that took up the fallows recently. This indicates the potential for increased pest infestation with increased adoption of the system by farmers. Multi-species fallows did not indicate any advantage over single species fallows in terms of either reduced pest incidence or increased biomass production.     

Nutrient Sources and Harvest Frequencies Impact Water Stable Soil Macro-Aggregates

We evaluated the effects of nutrient sources [cattle manure, poultry litter, urea, chemical fertilizers [nitrogen (N), phosphorus (P) and potassium (K)], inter-seeded crimson clover (Trifolium incarnatum L.), and a control], and harvest frequency (single and twice) on water stable soil macro-aggregates through wet sieving. The experiment was performed in a split-plot design with four replications. In most cases, single harvest resulted in more water stable soil aggregates than twice harvest. This could be due to less soil disturbance and uninterrupted root exudate supplies for soil microbes. Application of cattle manure and poultry litter significantly increased the percent of water stable soil macro-aggregates to the extent of 47% compared with chemical (NPK) fertilizer application. These results demonstrated that vigilant recycling of these animal wastes could improve soil aggregate formation. However, long-term monitoring of this practice is needed to evaluate system sustainability and profitability.     

An improvement on the papadakis covariate to account for spatial variation

The Papadakis covariate is commonly used to account for spatial variation in agricultural field experiments. However, it is calculated from the observed yield, and is affected by unexpected land discontinuity. To address this problem, we propose two extensions. First, we introduce a kriged covariate which is based on spatial information in the field. Two covariates, namely the kriged residual and the kriged Papadakis residual, are discussed. The second extension is a modification of the conventional Papadakis covariate that assigns equal weight to neighboring plots, regardless of their distance from the point of interest. The proposed covariate (a modified Papadakis covariate) assigns different weights to plot yield according to their spatial position. The proposed extensions are compared to the conventional Papadakis covariate using field data from Ethiopia. Simulations were conducted to evaluate the performance of these covariates. The number of neighbors needed to compute the proposed covariate are determined by the range of the variogram.     

Analysis of yield variability in winter wheat due to temporal variability,and nitrogen and phosphorus fertilization

Abstract

Field average based recommendations have been a common practice for recommending the major crop nutrients nitrogen (N) and phosphorus (P). The problem is yield will not be the same from year to year with application of the same amount of recommended rate of fertilizer. The objectives of this study were to demonstrate how recommendations generated using nutrient response experiments were dynamic; and to assess the relative contribution of temporal variability, N and P fertilizers on winter wheat grain yield and N concentration. Twelve factorial combinations of four N (0, 56, 112, and 168 kg ha^?1) and three P (0, 14.5, and 29 kg P ha^?1) rates were evaluated in a randomized complete block design with three replications at Perkins, Oklahoma. To address the first objective, ANOVA and orthogonal polynomial contrasts were used. To address the second objective, a ten predictor variable multiple linear regression model with two quantitative variables and their interaction (N, P and N×P) and seven-year variables was evaluated and a reduced model containing seven variables was generated. Wheat grain yield showed three distinct responses to N rates: Linear, quadratic and no response. These individual year data show that it is not always appropriate to use results of nutrient response experiments to estimate next year's N fertilizer requirement due to apparent temporal variability in the results. Wheat only responded to P during the first two years of the study. The reduced model from the regression analysis revealed that most of the variability in grain yield was accounted for by five individual indicator years and N only. High variability across years in grain yield and fertilizer (N and P) response, even between years of similar grain yield, is an indication of a given season's production dependence on factors other than N and P.