Contour Farming Research Articles

Erosion and control options in the La Ciénega Microbasin in Malinaltepec, Guerrero, Mexico

Objective: To estimate the water erosion rate in the La Ciénega Microbasin inMalinaltepec, Guerrero, Mexico, and to evaluate control options.Design/methodology/approach: Potential erosion rate, actual erosion rate, anderosion control were estimated using the Universal Soil Loss Equation (USLE) underthree conservation practices: contour plowing, successive land terracing, and liveterracing with vetiver grass (Chrysopogon zizanioides (L.) Roberty).Results: High erosion potential is shown by 99.18% of the microbasin surface area.Due to vegetation, only 41% of the surface area demonstrates high or very high actualerosion, 53.6% light, and 4.6% moderate. A living barrier using vetiver is the onlyconservation practice, of those assessed, that effectively diminished erosion.Study limitations/implications: The lack of accurate data on rain-induced erosion wasa limiting factor in this study. Findings/conclusions: The La Ciénega Microbasin has a high risk of erosion andcurrent erosion is a problem on agricultural land. The most effective option is livingbarriers using vetiver.

Influence of conservation tillage on Greenhouse gas fluxes and crop productivity in spring-wheat agroecosystems on the Loess Plateau of China.

The effects of climate change such as dry spells, floods and erosion heavily impact agriculture especially smallholder systems on the Northwestern Loess Plateau of China. Nonetheless agriculture also contributes to global warming through the emission of greenhouse gases such as CO2, CH4 and N2O. Yet this complex conundrum can be alleviated and mitigated through sound soil and water management practices. Despite considerable literature on Conservation Agriculture (CA) as a strategy to improve the resilience and mitigation capacity of agroecosystems, there is still paucity of information on the impacts of CA on crop production and environmental quality on the Plateau. In order to fill this gap this study examined the effects of no-till and straw mulch on crop productivity and greenhouse gas fluxes in agroecosystems on the Plateau where farmers’ common practice of conventional tillage (CT) was tested against three CA practices: conventional tillage with straw mulch (CTS), no-till (NT) and no-till with straw mulch (NTS). The results indicated that all three CA practices (CTS, NT and NTS) markedly increased soil water content (SWC), soil organic carbon (SOC) and soil total nitrogen (STN) but reduced soil temperature (ST). Average grain yields were 854.46 ± 76.51, 699.30 ± 133.52 and 908.18±38.64 kg ha-1 respectively under CTS, NT and NTS indicating an increase by approximately 33%, 9% and 41% respectively compared with CT (644.61 ± 76.98 kg ha−1). There were significant (p < 0.05) reductions of Net CO2 emissions under NT (7.37 ± 0.89 tCO2e ha−1y−1) and NTS (6.65 ± 0.73 tCO2e ha-1y-1) compared with CTS (10.65 ± 0.18 tCO2e ha−1y−1) and CT (11.14 ± 0.58 tCO2e ha−1y−1). All the treatments served as sinks of CH4but NTS had the highest absorption capacity (−0.27 ± 0.024 tCO2e ha−1y−1) and increased absorption significantly (p < 0.05) compared with CT (−0.21 ± 0.017 tCO2e ha−1y−1); however, CA did not reduce emissions of N2O. These had an influence on Global warming potential (GWP) as NT and NTS resulted in significant reduction in net GWP. Grain yield was significantly correlated positively with SOC and STN (p < 0.05); ecosystem respiration was also significantly correlated with SWC and ST while CH4 flux was highly correlated with ST (p < 0.001). Crop yield and GHG responses to CA were controlled by soil hydrothermal and nutrient changes, thus improving these conditions through adoption of sustainable soil moisture improvement practices such as no-till, straw mulch, green manuring, contour ploughing and terracing can improve crop resilience to climate change and reduce GHG emissions in arid and semi-arid regions.

CONSERVATION AGRICULTURAL PRACTICES: DETERMINANTS AND EFFECTS ON SOIL HEALTH FOR SUSTAINABLE PRODUCTION IN NORTHERN GHANA

Research background: The threat from climate change remains a major concern especially for developing economies like Ghana. Hence, agricultural practices that are environmentally friendly and improves soil health are very necessary for building resilience. Purpose of the article: The present study investigated the determinants of conservation agricultural practices in northern Ghana as well as the effect of these practices on soil health for sustainable production. Methods: Using cross-sectional data collected by the International food policy research institute from 1284 households, a multivariate probit model was first performed to identify the determinants of conservation agricultural practices while the inverse probability weighted regression adjustment was employed to establish the effect of conservation agricultural practices on soil health. Findings & value added: Results from the multivariate probit model showed that socioeconomic and institutional factors as well as different household-specific factors, influence farmer’s decisions to engage in various conservation agricultural practices. Crop rotation, fallowing, contour ploughing or pit planting and manure application were found to have a positive effect on soil health through improved resilience to soil erosion. The study concludes that conservation agricultural practices will be useful in Ghana’s quest of achieving zero hunger since the conservation agricultural practices ensure that food is produced for the present generations without compromising the soil health for further productions. Hence, the current Ghanaian government’s flagship programme dubbed ‘planting for food and jobs’ should include conservation agriculture as a priority module in its framework so that households could both increase their output while maintaining the quality of the soil.

English

This research was conducted to study the effects of climate variables such as rainfall, temperature, and relative humidity on cowpea yield, and evaluated in Gombe State, Nigeria, during the period of 2009 to 2018 (one decade). The ex-post facto research design was adopted for the study, utilizing secondary data obtained from meteorological and agronomic data collected from the Metrological Office and agronomic data from the Ministry of Agriculture, Gombe State. Both data were collected and analysed using analysis of variance (ANOVA), Pearson Product Moment Correlation and Simple Linear regression. The study found that there is a negative relationship between rainfall, relative humidity and area of land/ha, while a positive relationship existed for temperature and cowpea yield over the period under study decade. The study revealed that all the parameters-rainfall temperature, relative humidity contributes 61% to climate variation in the study area. The study among others recommended that cowpea farmers should adopt new measures such as early planting, use of resistant varieties, contour farming to conserve water and supplementary irrigation to cope with the negative effects of climate change on cowpea yield and increases cowpea production in Gombe State, Nigeria. Key word: Climate variation, yield, cowpea.&nbsp;

Identification of specific areas for water conservation measures using Geoinformatics approach

The accessibility of water resources is depleting everyday on a spatial and temporal scale, while water demand is expanding reliably. With this view, the investigation is an endeavour to identify the best locations appropriate for water conservation measures in West Midnapur, Purulia, and Bankura regions of West Bengal, India, using Geoinformatics approach. In this study, administrative boundaries have been considered to get the best locations for all water conservation measures. Then, these locations are shown district wise by considering administrative boundaries. In India, most of the funds are allocated based on administrative boundaries so it is necessary to suggest water conservation measures based on administrative boundaries. The Digital Elevation Model (DEM), Landsat 7 satellite imagery, and daily precipitation data of the year 2011 were used to get ready layers of the slope, and land use land cover. The runoff and runoff potential zones were determined using the Soil Conservation Service Curve Number (SCS-CN) method in the Geographic Information System (GIS) environment. The weights were assigned to thematic layers (slope and runoff coefficient) and ranks were given to these features; then, score was calculated to find out the Water Conservation Potential Index (WCPI). Thematic layers were integrated using ArcGIS software to generate water conservation potential maps for both surface water harvesting structures and groundwater recharge measures. Based on the values of WCPI, zones suitable for surface water harvesting structures and groundwater recharge measures were identified using slope, soil, drainage order, and rainfall as suitability criteria. The outcomes demonstrated that 479, 1884, 1400, 808, and 140 locations in all the three regions were suitable for percolation ponds, farm ponds, check dams, contour bunds, and contour trenching respectively. This research will be useful for policymakers to allocate government funds based on administrative boundaries.

How to model the effect of mechanical erosion control practices at a catchment scale?

Conservation agriculture practices are a crucial factor in mitigating and controlling erosion by water. To address water erosion estimates, most environmental models use the USLE, RUSLE, and MUSLE models. Management practices that affect soil erosion by modifying the flow pattern, such as contour farming, strip farming, or terracing, are represented within these models as a support practice (P) factor. However, due to the difficulty in accurately mapping the P-factor, many studies choose to ignore it, using only the default value P-factor 1which represents the absence of sowing at the level or cultivation in strips. This study proposes a methodology that evaluates the current P-factor based on the angle between the crop row orientation and the elevation contour lines. The method was tested in four areas under soybean crop fields in southern Brazil, totaling 25 km2. The reason for choosing four areas is to select different characteristics of rural properties and topographic conditions. The ideal values of the P-factor are expected to be between 0.5 and 0.6; however, in our case, a P-factor greater than 0.8 was obtained in 60% of the area, indicating the low occurrence of contour farming reduces erosion rates. The results show that policymakers could potentially use this methodology (angle between the crop rows and contour lines) to run soil-erosion risk scenarios for a broader application of contour farming. This allows the P-factor to be quantified via a thematic map instead of assigning uniform P-factor values. With a detailed study of the P-factor on the slopes, there is a better understanding of where to target support practices to reduce erosion.

Are perception and adaptation to climate variability and change of cowpea growers in Mali gender differentiated?

Understanding the gender dimension of climate change perception and choice of adaptation strategies is crucial for policy recommendations that foster the development and integration of gender-responsive climate-smart agricultural interventions into agricultural development programs. This study determined the differences in the perception and choice of adaptation strategies between men and women farmers in Cinzana in the Segou region of Mali. The study used questionnaire interviews involving 260 farmers (49% women) and focus group discussions for data collection. Data were analyzed using descriptive statistics and multinomial logit model to understand the determinants of the level of adoption of adaptation strategies. The results showed that, irrespective of gender, majority of farmers perceived climate change as extended period of droughts, shortened duration of rains, increased frequency of strong winds and increased day and night temperatures. While climate change perception was similar between men and women, choice of adaptation strategies differed significantly in most instances. Women farmers were generally low adopters of crop and varieties-related strategies, soil and water conservation technics (contour farming, use of organic manure), etc., compare to men. Notably, being the household head, age and the availability of free labor were found to positively increased farmers’ probability of adopting many adaptation strategies. The study recommends improving women’s access and control of production resources (land, labor) as means to improving their adoption of adaptation strategies.

Impacts of different monoculture types on stream benthic macroinvertebrate and fish communities

Agribusiness is one of the main economic activities in Brazil, which caused the removal of much of its natural vegetation for the expansion of monoculture areas. Once aquatic environments have a direct relationship with the surrounding terrestrial environment, it is essential to understand the monocultures’ impact on adjacent streams and, especially, how aquatic communities react to these impacts. Our aim was to verify the effects of different monoculture types on stream benthic macroinvertebrate and fish communities’ structure. We compared the environmental characteristics and these communities’ structure in four streams located in native vegetation areas and four in each of three monoculture types (sugarcane, citrus, and eucalyptus), all belonging to the Paranapanema River basin, Southeastern Brazil. We found lower pH and dissolved oxygen and higher total phosphorus and fine substrate values in monoculture streams and these variables were also related to the lower abundance of macroinvertebrate groups more sensitive to environmental impacts. However, we did not find differences in fish communities or in their relationship with the different environmental characteristics observed. We also did not observe differences between the monoculture types in all comparisons made, which demonstrate that these plantations, although have different cultivation characteristics, cause similar negative impacts in the streams. Our study demonstrates the physical and chemical impacts of monoculture development on stream headwater communities. Regulatory measures such as increased riparian vegetation and contour farming and terracing may be critical to protect and restore headwater streams from monoculture impacts.

Comparison of indigenous and mechanical conservation technologies for shifting cultivation agro-ecology of north-eastern Himalaya

Traditional shifting cultivation with reduced cycle aggravates soil erosion more rapidly in north-eastern India. To address this issue, an erosion plot experiment was conducted from January 2013 to December 2014 at Wokha district of Nagaland, India with five treatments viz., control (T1), bench terraces (T2), contour bunds (T3), bamboo fence (T4) and wooded log (T5). Soybean (cv. JS-335) was grown with the standard package and practices. The main objective was to find out the best suitable soil conservation measure to arrest the soil and nutrient loss. The annual soil erosion was measured the highest in treatment T1 (70.1 t ha−1) followed by T5 (25.2 t ha−1), T4 (13.5 t ha−1), T3 (6.20 t ha−1) and T2 (0.94 t ha−1) in the first year. In the second year, the extent of soil erosion was reduced, and it followed the order of T (50.7 t ha−1) < T5 (20.3 t ha−1) < T4 (8.92 t ha−1) < T3 (4.62 t ha−1) < T2 (0.54 t ha−1). Subsistent amount of clay, silt, sand, soil organic matter, major nutrients and micronutrients were lost in both the years. It was also found that the monetary loss in terms of only nitrogenous and potassium fertilizers was contributed 74.9 to 83.2% in the year 2013 and 50.7 to 70.8% in the year 2014, respectively. Considering all treatments across the years, bench terracing across the slope (T2) is found as the most suitable, but economic point of view, contour bund (T3) may be recommended for this region.

Efficacy of different soil conservation measures on soil properties and erodibility characterization of Babina watershed of district Jhansi in Bundelkhand region

The study was carried out in Babina watershed of district Jhansi in Bundelkhand region of Uttar Pradesh (India) under Operational Research Project for Resource conservation on sustained basis. The Bedaura (Mar) and Chamraua (Kabar) soil series of watershed representing typical black soil were richer in water stable aggregate and less erodible as compared to Imilia (Parwa) and Amarpur (Rakar) series (red soil) and follow the erodibility order as: Bedaura < Chamraua < Imilia < Amarpur The result represented that erodibility among the project area varies according to soil conservation measures adopted. Revines lands with conventional up and down cultivated soils are more erodible in comparison to land treated by various soil conservation practices On the basis of erosion ratio, erosion index and water stable aggregate as principle indices of erodibility, soil under various soil conservation practices may be arranged in the order of : Conventional method > peripheral bund > Sunken structure > check dam > contour bunding > land levelling and field bunding > submerged bund with vegetative > vegetative barriers. The erosion ratio was significantly and positively correlated with suspension percentage (r=0. 214), bulk density (r=0. 0.933**), particle density (r=0. 732**), hydraulic conductivity (r=0. 892**), pH (r=0. .734**), EC (r=0. 832**), dispersion ratio (r=0.961**), erosion index (r=0.986**), clay ratio (r=0.892*) and silt/clay ratio (r=0.904*) while significantly and negative correlated with silt (r=-0.700**), clay (r=- 0.933**), moisture equivalent (r=-0.912**), water holding capacity (r=-0.900**), water stable aggregate (r=-0.898**)., organic carbon (r =-0. 0.8306**), Total N (r =-0.8025**), Available P2O5 (r=-0. 7931**) and K2O (r=-0. 738**), Ca++ (r=-0. 516**), exchangeable Mg++(r=- 0.625**) and clay/ moisture equivalent (r=-0.904**). Among adopted eight soil conservation practices, soil erodibility decreased with increasing clay content. Soils of Babina watershed are erosive in nature and require warrant and prompt attention for implementing intensive soil conservation measures in the entire watershed in order to subside the havoc of soil erosion with in safe limits because adopted soil conservation measures are variably effective to controlling the erosion. Due to adoption of integrated watershed development technology viz. soil conservation measures with land development techniques, high yielding crop varieties, timely sowing with optimum seed rates, use of proper manures and fertilizers and irrigation on critical stage, the cropping intensity and average yield of crops, oilseeds and pulses have been increased in sustainable manner resulting improvement in Benefit: costs ratio. Simultaneously, socio-economic condition has also uplifted considerably due to diversification of agriculture and judicious use of natural resource. Outcomes of this study are of great importance in strategic land use planning and for execution of different intensity of soil conservation programme.

A Soil Water Assessment Tool (SWAT) Modeling Approach to Prioritize Soil Conservation Management in River Basin Critical Areas Coupled With Future Climate Scenario Analysis

About 44% of the Indian landmass experiences the adverse impact of land degradation. This loss of sediments caused by soil erosion reduces the water quality of local water bodies and decreases agricultural land productivity. Therefore, decision-makers must formulate policies and management practices for sustainable management of basins that are cost-effective and environment friendly. Application of the best management practices (BMPs) to properly manage river basins is difficult and time-consuming. Its implication under various climate change scenarios makes it more complicated but necessary to achieve sustainable development. In this study, the soil and water assessment tool (SWAT) model was employed to prioritize the Tons river basin’s critical areas in the central Indian states coupled with future climate scenario analysis (2030–2050) using Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios. The SWAT model was calibrated and validated for simulation of streamflow and sediment yield for daily and monthly scales using the sequential uncertainty fitting (SUFI-2) technique. The values of coefficient of determination ( R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and root mean square error (RMSE)-observations standard deviation ratio (RSR) were .71, .70, −8.3, and .54, respectively during the calibration period, whereas for validation the values were .72, .71, −3.9, and .56, respectively. SWAT model underestimated the discharge during calibration and overestimated the discharge during validation. Model simulations for sediment load exhibited a similar trend as streamflow simulation, where higher values are reported during August and September. The average annual sediment yield of the basin for the baseline period was 6.85 Mg ha−1, which might increase to 8.66 Mg ha−1 and 8.79 Mg ha−1 in the future years 2031–2050 and 2081–2099, respectively. The BMPs such as recharge structure, contour farming, filter strip 3 and 6 m, porous gully plugs, zero tillage, and conservation tillage operations have been considered to evaluate the soil and water conservation measures. Recharge structure appeared to be the most effective measure with a maximum reduction of sediment by 38.98% during the baseline period, and a 37.15% reduction in the future scenario. Sub-watersheds, namely SW-8, SW-10, SW-12, SW-13, SW-14, SW-17, SW-19, SW-21, SW-22, and SW-23, fall under the high category and are thus considered a critical prone area for the implementation and evaluation of BMPs. Compared to the baseline period, the effectiveness of BMPs is slightly decreasing in the 2040s, increasing in the 2070s and decreasing in the 2090s. Recharge structure and filter strip 6 m have been found to nullify the high soil erosion class completely. Overall, SWAT model simulations under the RCP 8.5 scenarios were observed to be reliable and can be adopted to identify critical areas for river basins having similar climatic and geographical conditions.

Best management practices scenario analysis to reduce agricultural nitrogen loads and sediment yield to the semiarid Mar Menor coastal lagoon (Spain)

Agriculture is a major source of diffuse pollution, where nitrogen and sediment pollution of water bodies are its main associated environmental impacts. Best management practices are effective tools for preventing and minimizing water pollution. Water quality models and model-based scenario analyses are useful tools for assessing impacts of best management practices and to identify appropriate strategies on the watershed scale. This study was conducted in the southernmost Mar Menor basin, one of the largest saltwater coastal lagoons in Europe and threatened by diffuse nutrient and sediment export from the agricultural landscape. This study evaluates the impact of several management practices on nitrogen and sediment loads, and horticultural crop yield, to identify an appropriate management strategy on the watershed scale. Both structural and nonstructural management practices scenarios were evaluated: three scenarios representing field operations, two coastal line buffers, a new fertilizer management strategy and a change in the productive cultivation system from three-crop rotation to two-crop rotation. Each management practice reduced a certain type of diffuse pollution and, therefore, a combined set of changed management practices is necessary to cope with all agricultural pollution types. Contour farming, combined with hedgerow field borders, was effective in sediment yield and surface organic nitrogen export reduction terms, while improved fertilizer management reduced surface nitrate export and leaching with minimal impacts on crop yields.

Contour Farming Improves Soil Moisture and Dry Land Crop Productivity on Rainfed Alfisols

A field experiment was conducted during kharif 2019 on Alfisols to find out the impact of intercropping and contour farming on total system productivity and soil moisture, under rainfed conditions. The results revealed that intercropping of mung bean with pigeon pea (MB+PP 4:1) was found to be highly productive and economical than corn+ pigeon pea (C+PP 4:1). Further, contour farming (CF) gave higher corn equivalent yield (CEY) and conserved more moisture than up down farming (UDF). The combination of MB+PP and CF has significantly out yielded (8019 kg ha-1) the MB+PP under UDF (6612 kg ha-1), C+PP under CF (4026 kg ha-1) and C+PP under UDF (3393 kg ha-1) in terms of CEY. Further, MB+PP and CF association recorded higher soil moisture, nutrient uptake, partial factor productivity (PPFN: 253.4 kg kg-1), agronomic efficiency of applied N (AEN: 46.79 kg kg-1) and rainfall use efficiency (RUE: 12.2 kg ha mm-1) besides higher net returns (Rs. 82608 ha-1) and B:C ratio (2.41).

Soil erosion risk and sediment yield assessment with universal soil loss equation and GIS: in Dijo watershed, Rift valley Basin of Ethiopia

Soil erosion is the main drivers in the world and Ethiopia in particular. This study has been conducted at Dijo watersheds in the Rift valley Basins of Ethiopia to estimate soil erosion rate and identify erosion hotspot areas for proper planning using Geographic Information System and Universal Soil Loss Equation adapted to Ethiopian condition. 64 years mean annual rainfall data for estimating erosivity factor, digital soil map for estimating soil erodibility factor, Digital Elevation Model for estimating topographic (LS) factor, Land use land cover for cover factor detection from Ethiopian ministry of water resources. The result reveals that the soil loss ranges from 0 ton/ha/year in flat slope to 38.09 ton/ha/year from steep slopes. The average soil loss rate is 2.2 tons per hectare per year and has been classified into three erosion severity classes as very low, low and moderate. The result also reveals that most of the watershed erosion severity evaluated under very low and low soil erosion severity classes covering 97.3% of the watershed areas which is due to the effect of mixed plantation of various tree and terraces. However, moderate soil erosion in the upper parts of the watershed could be due to the inherent characteristics of vertisols, lack of vegetation cover and terraces which should be given first priority for conservation interventions. From the gross soil erosion, 43,762 ton/year sediment yields have been estimated at watershed outlet. Policy aim at keeping land productivity will need to focus to reduce low and moderate soil erosion through terracing, inter-cropping, contour farming, strip cropping, conservation tillage, mulching and biological stabilizers based on their slope range, soil type and land use type. The current finding on erosion was evaluated based on the past 10 years land use land cover scenario; therefore, soil erosion might be reduced if the current land use land cover scenario considered. Finally, the integration of USLE and GIS is an effective tool in mapping the spatial distribution of soil erosion from the entire watershed. The moderate and low soil erosion severity areas should be managed through terracing, inter-cropping, contour farming, strip cropping, conservation tillage, mulching and biological stabilizers based on their slope range, soil type and land use type. Free grazing and cultivation of steep slope(Northern parts) contributed for moderate soil erosion in the watershed should be managed by cut–carry system, limiting the number of cattle units to be grazed in the specific plot of land and leaving the marginal steep slope areas with no ground covers for natural regeneration. Finally, the current finding on erosion was evaluated based on the past 10-year land use land cover scenario. Therefore, the soil erosion could be reduced if the current land use land cover scenario is considered.

Cost-Benefit Analysis of On-Farm Climate Change Adaptation Strategies in Ghana

Climate change continues to hamper crop-based systems across sub-Sahara Africa. Adaptation strategies prove to be effective at improving production and enhancing livelihoods of farm households. This study employs Cost-Benefit Analysis (CBA) to assess the perceived economic profitability of adopting various on-farm climate change adaptation strategies among farmers in Zabzugu and South Tongu districts in the north and south of Ghana. A simple random sampling approach was used to select 300 farmers who had previously benefited from climate change projects. Major strategies adopted in both districts were: changing of planting dates, planting early maturing varieties, row planting, seed refilling and planting drought tolerant varieties. Adoption intensity was high in Zabzugu district compared to the South Tongu District. Generally, the adoption of each strategy was perceived to be profitable since the estimated average benefits outweighed the average costs. However, the most profitable strategies were strip cropping, repeated sowing, refilling, zero tillage and row planting. Less profitable strategies included land rotation, mixed farming, early planting, tractor ploughing and “A-frame” contour farming. Among others, drought tolerant varieties of rice, maize and soybeans, as well as zero tillage, repeated sowing and strip cropping, should be promoted and farmers encouraged to adopt these practices for enhanced benefits.

Performance Assessment of Erosion Remediation Measures and Proposal of The Best Management Practices for Erosion Control in Sebeya Catchment, Rwanda

Soil erosion is an environmental concern that affects agriculture, wildlife and water bodies. Soil erosion can be avoided by maintaining a protective cover on the soil to create a barrier to the erosive agent or by modifying the landscape to control runoff amounts and rates. This research is focused on Sebeya catchment located in the Western Province of Rwanda. Sebeya catchment is one of the most affected areas by soil erosion hazards causing loss of crops due to the destruction of agricultural plots or riverbanks, river sedimentation and damages to the existing water treatment and hydropower plants in the downstream part of the river. The aims of this research were to assess the performance of erosion remediation measures and to propose the Best Management Practices (BMPs) for erosion control in Sebeya catchment. Using literature review, site visits, questionnaire and interviews, various erosion control measures were analyzed in terms of performance and suitability. Land slope and soil depth maps were generated using ArcGIS software. The interview results indicated that among the 22 existing soil erosion control measures, about 4.57% of farmers confirmed their existence while 95.43% expressed the need of their implementation in Sebeya catchment. Furthermore, economic constraints were found to be the main limitative factors against the implementation of soil erosion control measures in Sebeya catchment. Also, the majority of farmers suggest trainings and mobilization of a specialized technical team to assist them in implementing soil conservation measures and to generalize the application of fertilizers in the whole catchment. Finally, soil erosion control measures including agro-forestry, terraces, mulching, tree planting, contour bunds, vegetative measures for slopes and buffer zones, check dams, riverbanks stabilization were proposed and recommended to be implemented in Sebeya catchment.&#x0D; Keywords: Erosion control measures, Sebeya catchment, Rwanda

Nutrient mitigation under the impact of climate and land-use changes: A hydro-economic approach to participatory catchment management

Excessive nutrient loadings into rivers are a well-known ecological problem. Implemented mitigation measures should ideally be cost-effective, but perfectly ranking alternative nutrient mitigation measures according to cost-effectiveness is a difficult methodological challenge. Furthermore, a particularly practical challenge is that cost-effective measures are not necessarily favoured by local stakeholders, and this may impede their successful implementation in practice. The objective of this study was to evaluate the cost-effectiveness of mitigation measures using a methodology that includes a participatory process and social learning to ensure their successful implementation. By combining cost data, hydrological modelling and a bottom-up approach for three different European catchment areas (the Latvian Berze, the Swedish Helge and the German Selke rivers), the cost-effectiveness of 16 nutrient mitigation measures were analysed under current conditions as well as under selected scenarios for future climate and land-use changes. Fertiliser reduction, wetlands, contour ploughing and municipal wastewater treatment plants are the measures that remove nutrients with the highest cost-effectiveness in the respective case study context. However, the results suggest that the cost-effectiveness of measures not only depends on their design, specific location and the conditions of the surrounding area, but is also affected by the future changes the area may be exposed to. Climate and land-use changes do not only affect the cost-effectiveness of measures, but also shape the overall nutrient loads and potential target levels in a catchment.

Flood investigation and adaptation strategies through best management practices in an ungauged basin in Southwest Nigeria

ABSTRACT Morphometric analysis and hydrologic modeling was employed to investigate flooding, and test Best Management Practices (BMPs) in an ungauged basin. The Soil and Water Assessment Tool (SWAT) was employed to model the annual runoff/sub-basin for the year 2015, and to test BMPs –contour farming, terraces, and check dams for runoff reduction. The sub-basins were classified into low, medium, and high flood susceptibility. The rainfall-runoff hydrograph showed that runoff peaks closely follows rainfall peaks. Contour farming, terraces, and check dams presented a runoff decrease of 12.06%, 21.06% and 10.05%. The study provides good reliability in flood investigations and testing of BMPs.

Farmers Characteristics in Relation to Soil and Water Conservation: The Case of Yongdeng County, China

Many soil and water conservation technologies have been promoted and spread to encourage the sustainable use of resources by small-scale farmers, but soil degradation continues intensively. The objective of this study therefore, was to identify the measures of Soil and Water Conservation, the factors that inform the adoption and use Soil and Water Conservation measures and evaluate the limitations to realize and maintain of these conservation practices. This study was done in Yongdeng County which falls under the governance of the city-level prefecture of Lanzhou, the capital of Gansu Province. One hundred farmers were randomly selected. Primary data was obtained through interviews and group discussion with farmers, and agricultural extension workers and field survey. The results revealed that the level of education and farm size did not affect the use of SWC measures. Unlike formal education, membership of the group of farmers was significant and had positive correlation with SWC measures. SWC education and training was significant and had a positive impact on the use of SWC measures. The study found that SWC structures commonly used by farmers in the study area include terraces (30%), contour ploughing (20%) and the use of drains. The agronomic practices commonly used are agroforestry, crop rotation and the use of grass strips. Farmers identified poverty, ignorance and lack of technical advice as the main obstacles to realizing the full potential of soil and water conservation in the area. Poorly laid out soil conservation structures were also accelerating soil erosion. These results show that, in order to ensure adequate soil and water conservation, particular attention must be paid to institutional and economic factors. Also, to encourage farmers’ participation in education and extension training on SWC, it is vital to strengthen the relationship between extension workers and farmers.

Morpho-lithostructural analysis of Ala River basin for flood risk assessment: geospatial techniques intervention

An integrated approach of morphometric and litho-structural studies for flood risk assessment of Ala River Basin (ARB) in Akure city, southwestern Nigeria aided by geospatial techniques was carried out. The Ala River Basin comprises of four sub-basins covering a total area of 427km2 with fourth stream order of dendritic and sub-trellis drainage patterns. The values obtained for the morphometric features such as Form Factor, Circularity Ratio, Elongation Ratio, Stream Frequency, and Relief Ratio and Compactness Coefficient for ARB revealed an elongated basin type, posing a great flood threat to the urban community. Drainage density for all the sub-basins is very low, typically a coarse type that supports ample time for overland flow. All the lithological units are characteristically impermeable with low lineaments density. Thinness of the soil profile, and frequency of stream flow showed good relation to low infiltration with attendant high runoff leading to flood events in the upstream section. Flood sub-basin wise prioritization was carried out by employing the result obtained from morphometric classification and structural analysis. Different weightages were assigned to the different morphometric and structural parameters for the four sub-basins based on flood potentials. Ala River sub-basins have been classified into three namely; high, moderate and low based on flood potentials. The sub-basin I and II located at the upstream section are highly vulnerable to floods, while sub-basin III and IV located at the downstream section are not presently vulnerable to flooding respectively. The flood water in the flood threatened sub-basins (I and II) can also be harvested through siting and construction of natural groundwater recharge structures such as check dams and contour bunds.