An integrated framework for improving watershed management planning.

Proper land use and management (LUM) planning is pivotal to curbing land degradation and ensuring sustainable use of limited watershed resources. Despite decades of research and development efforts, land degradation remains a serious environmental problem in many parts of the world. Issues regarding the sustainability of current LUM initiatives are due to poor linkages between the ecological and socio-economic dimensions of LUM decisions, and an integrated framework allowing LUM interventions to be properly planned and implemented is lacking. In this study, we developed an integrated framework to identify, evaluate, and propose LUM alternatives with ecological and socio-economic benefits. The framework comprises six components: (i) identification of land use problems and setting of objectives, (ii) identification of the best-performing land use-based integrated solutions, (iii) formulation of LUM alternatives and modeling of key indicators, (iv) cost-benefit analysis, (v) evaluation of the LUM alternatives with stakeholders engagement, and (vi) communication of the LUM alternatives to relevant stakeholders to obtain institutional and financial support for implementation. To demonstrate the use of this framework, we conducted a case study in the Aba Gerima watershed of the Upper Blue Nile basin in Ethiopia. This study used extensive plot- and watershed-scale observations (2015-2019) obtained under both conventional and improved sustainable land management practices. We analyzed changes in runoff, soil loss, soil organic carbon (SOC) stock, and land productivity of five LUM alternatives as compared to a baseline scenario (existing farming practices). The results showed that the LUM alternatives reduced runoff by 11-71% and soil loss by 66-95%, and SOC stock and watershed-scale land productivity were improved by 36-104% and 48-134%, respectively. Evaluation of LUM alternatives by stakeholders, including land users, policy makers, and researchers, produced divergent results. In particular, land users prioritized implementation of sustainable land management practices without altering existing land uses. The integrated framework developed in this study can serve as a valuable tool for identifying, evaluating, and proposing LUM alternatives and facilitating decision-making in planning and implementation of LUM practices in watersheds experiencing land degradation.

Exploring the variability of soil nutrient outflows as influenced by land use and management practices in contrasting agro-ecological environments.

Improving our understanding of how different land uses and management practices affect soil nutrient outflows in sub-Saharan Africa could aid in developing sustainable practices. The objective of this study was to analyse the variation in outflows of soil total nitrogen (TN) and available phosphorus (Pav) as influenced by land use types (cropland, grazing land, and bushland) and land management practices (soil bunds for cropland and exclosures for non-croplands) in the three contrasting agro-ecological zones of the Upper Blue Nile basin, Ethiopia. Field data were collected for TN and Pav outflows by water erosion (Eo), leaching (Lo), product harvest (Ho), and gaseous emissions (Go) from 18 runoff plots (30 m × 6 m) for two years (2018-2019). TN and Pav losses significantly varied (p < 0.05, p < 0.01) among agro-ecological zones, land use types, and management practices. Losses of TN ranged from 39.6 to 55.5 kg ha-1 yr-1 and those of Pav from 4.1 to 5.9 kg ha-1 yr-1, with a total replacement cost of US$26-38 ha-1 yr-1. Nutrient losses and cost generally increased from lowland (Dibatie) to midland (Aba Gerima) to highland (Guder), although the highland and midland sites did not differ significantly (p > 0.05) in nutrient losses. Cropland showed significantly higher TN and Pav losses than other land use types, but TN loss did not differ significantly between grazing and bushland. In all land use types at all sites, the magnitude of nutrient losses was Ho >Eo >Lo >Go. In plots with land management practices, TN and Pav losses associated with Eo, Lo, and Go were reduced on average by 44-76%, 9-47%, and 1%-36%, respectively. These practices were most effective to reduce Eo nutrient losses. Further study is required to analyzing the soil nutrient balance and identify priority areas for implementing mitigation measures.

Laser methane detector-based quantification of methane emissions from indoor-fed Fogera dairy cows.

OBJECTIVE: Portable laser methane detectors (LMDs) may be an economical means of estimating CH4 emissions from ruminants. We validated an LMD-based approach and then used that approach to evaluate CH4 emissions from indigenous dairy cows in a dryland area of Ethiopia. METHODS: First, we validated our LMD-based approach in Simmental crossbred beef cattle (n = 2) housed in respiration chambers and fed either a high- or low-concentrate diet. From the results of the validation, we constructed an estimation equation to determine CH4 emissions from LMD CH4 concentrations. Next, we used our validated LMD approach to examine CH4 emissions in Fogera dairy cows grazed for 8 h/d (GG, n = 4), fed indoors on natural-grassland hay (CG1, n = 4), or fed indoors on Napier-grass (Pennisetum purpureum) hay (CG2, n = 4). All the cows were supplemented with concentrate feed. RESULTS: The exhaled CH4 concentrations measured by LMD were linearly correlated with the CH4 emissions determined by infrared-absorption-based gas analyzer (r2 = 0.55). The estimation equation used to determine CH4 emissions (y, mg/min) from LMD CH4 concentrations (x, ppm m) was y = 0.4259x+38.61. Daily CH4 emissions of Fogera cows estimated by using the equation did not differ among the three groups; however, a numerically greater milk yield was obtained from the CG2 cows than from the GG cows, suggesting that Napiergrass hay might be better than natural-grassland hay for indoor feeding. The CG1 cows had higher CH4 emissions per feed intake than the other groups, without significant increases in milk yield and body-weight gain, suggesting that natural-grassland hay cannot be recommended for indoor-fed cows. CONCLUSION: These findings demonstrate the potential of using LMDs to valuate feeding regimens rapidly and economically for dairy cows in areas under financial constraint, while taking CH4 emissions into consideration.

Effect of Feeding Improved Grass Hays and Eragrostis Tef Straw Silage on Milk Yield, Nitrogen Utilization, and Methane Emission of Lactating Fogera Dairy Cows in Ethiopia.

The nutritionally imbalanced poor-quality diet feeding is the major constraint of dairy production in tropical regions. Hence, alternative high-quality roughage-based diets are required to improve milk yield and reduce methane emission (CH4). Thus, we tested the effects of feeding natural pasture hay, improved forage grass hays (Napier and Brachiaria Hybrid), and treated crop residues (Eragrostis tef straw) on nutrient digestibility, milk yield, nitrogen balance, and methane emission. The eight lactating Fogera cows selected for the experiment were assigned randomly to a 4 × 4 Latin square design. Cows were housed in well-ventilated individual pens and fed a total mixed ration (TMR) comprising 70% roughage and 30% concentrate. The four roughage-based basal dietary treatments supplemented with formulated concentrate were: Control (natural pasture hay (NPH)); treated teff straw silage (TTS); Napier grass hay (NGH); and Brachiaria hybrid grass hay (BhH). Compared with the control diet, the daily milk yield increased (p < 0.01) by 31.9%, 52.9%, and 71.6% with TTS, NGH, and BhH diets, respectively. Cows fed BhH had the highest dry matter intake (8.84 kg/d), followed by NGH (8.10 kg/d) and TTS (7.71 kg/d); all of these intakes were greater (p = 0.01) than that of NPH (6.21 kg/d). Nitrogen digestibility increased (p < 0.01) from the NPH diet to TTS (by 27.7%), NGH (21.7%), and BhH (39.5%). The concentration of ruminal ammonia nitrogen was higher for cows fed NGH than other diets (p = 0.01) and positively correlated with plasma urea nitrogen concentration (R² = 0.45). Feeding TTS, NGH, and BhH hay as a basal diet changed the nitrogen excretion pathway from urine to feces, which can help protect against environmental pollution. Estimated methane yields per dry matter intake and milk yield were decreased in dairy cows fed BhH, NGH, and TTS diets when compared to cows fed an NPH diet (p < 0.05). In conclusion, feeding of TTS, NGH, and BhH roughages as a basal diet to lactating dairy cows in tropical regions improved nutrient intake and digestibility, milk yield, nitrogen utilization efficiency, and reduced enteric methane emission.

Mitigating the anti-nutritional effect of polyphenols on in vitro digestibility and fermentation characteristics of browse species in north western Ethiopia.

Browse species are important sources of forage for livestock in Ethiopia, especially during the dry season, when the quality and quantity of green herbage is limited. However, browse species have anti-nutritional factors, such as polyphenols. This study evaluated the extent to which polyethylene glycol (PEG) can reduce the anti-nutritional effects of polyphenols whose extent is expected to vary depending on the species type and season on the in vitro fermentation of these plant samples. We selected ten browse species commonly used as livestock feed based on their tannin content, and sixty samples of the leaf and twig of these species were collected during the wet and dry seasons. The study was designed as 10 × 2 × 2 factorial arrangement with 10 browse species (Acacia nilotica, Crateva adonsonia, Dombeya torrida, Ekebergia capensis, Ensete ventricosum, Erythrina brucei, Maesa lanceolate, Sesbania sesban, Stereospermum kunthianum, and Terminalia laxiflora), 2 seasons (wet and dry) and 2 states of PEG (with and without PEG). The effects of tannin on the nutritive characteristics were also evaluated by adding PEG as a tannin-binding agent. The chemical composition and in vitro fermentation products of these samples differed significantly (p < 0.001) among browse species. Specifically, total extractable phenol (TEP) ranged from 26.3 to 250.3 g/kg, total extractable tannin (TET) from 22.8 to 210.9 g/kg, and condensed tannin (CT) from 11.1 to 141.3 g/kg, respectively. Season, species, and their interaction have a significant (p < 0.05) effect on the chemical composition and fermentation characteristics of most browse species. The addition of PEG increased gas production (GP), in vitro organic matter digestibility (IVOMD), metabolizable energy (ME) concentration, dry matter degradability (DMD), and volatile fatty acids (VFA), on average, by 76.8%, 47.9%, 42.2%, 21.2%, and 20.2%, respectively. Secondary polyphenols (TEP, TET, CT, and SCT) were significantly (p < 0.001) and negatively correlated with GP, IVOMD, ME, and VFA. Preferable species namely E. ventricosum, S. sesban, M. lanceolata, E. capensis, and A. nilotica were selected for supplementation in terms of their chemical composition, IVOMD, and mitigating effects of PEG on anti-nutritional functions of their secondary compounds. In conclusion, PEG markedly reduced the anti-nutritional effects of polyphenols and improved the in vitro fermentation of browse species harvested in contrasting seasons.

Effects of substituting concentrate mix with water hyacinth (Eichhornia crassipes) leaves on feed intake, digestibility and growth performance of Washera sheep fed rice straw-based diet.

The objective of this experiment was to determine effects of substituting concentrate mixture (CM) with water hyacinth (Eichhornia crassipes) leaves (WHL) at different inclusion levels of feed and nutrient intake, digestibility, and growth performance of Washera sheep. Twenty yearlings intact male sheep with initial body weight of 24.1 ± 1.68 kg (mean ± SD) were used in both 90 days of feeding and 7 days of digestibility trials. The experimental animals were arranged into four blocks of five animals based on their initial body weight. The dietary treatments used in the experiment were 100% concentrate mix (0WHL-T1), 50% WHL and 50% CM (50WHL-T2), 75% WHL and 25% concentrate mix (75WHL-T3), and 100% WHL (100WHL-T4). Rice straw was given ad libitum. The crude protein (CP) content of water hyacinth leaf is 14.4%. Dry matter digestibility was greater (p < 0.001) for 0WHL and 50WHL followed by 75WHL. The average daily weight gain was higher for 100% concentrate mix followed by 50 and 75% water hyacinth leave supplemented sheep. Therefore, wilted water hyacinth leave can safely substitute concentrate mix up to 75% and result in the optimum growth of Washera sheep from the feeding regime employed in this study.