Soil And Water Conservation Research Articles

Do Socio-economic Conditions and Personal Behaviour Influence the Adoption of Climate Change Mitigating Measures

This study aimed to identify the factors affecting farmers’ perception of climate change and the adoption of Soil and Water Conservation (SWC) measures as a mitigation strategy for climate change. From the existing literature review, the study has identified the factors that potentially influence the adoption of climate mitigation and adaptation technologies. The binary logit model was employed using survey data collected from the Agra district of Uttar Pradesh during the year 2018-19. Results show that about 60 per cent of households had a clear perception of climate change, and age, education, membership of groups, mass media exposure, and extension agency contacts were key influencing factors in farmers’ perception of climate change. Similarly, education, occupation, mass media exposure, awareness of climate change consequences, climate change perception, and attitude of farmers increase the probability of adopting soil and water conservation measures by the farmers in their fields. Therefore, the study results have significant implications for policies and campaigns promoting adopting climate-smart technologies to make the agricultural system more resilient to climate change.

Multiple adoption of climate-smart agriculture innovation for agricultural sustainability: Empirical evidence from the Upper Blue Nile Highlands of Ethiopia

Adoption of appropriate climate smart innovations is the major step towards enhancing food security, building climate resilience capacity as well as reducing or removing GHG emissions from smallholder farms to sustainably maintain agricultural livelihoods. The purpose of this paper is to investigate the rate, intensity, and determinants of multiple adoptions of climate-smart agriculture innovations among smallholder farmers in Ethiopia's Upper Blue Nile Highlands. All Climate Smart Agriculture (CSA) innovations have a synergistic effect on the adoption of other innovations, with the exception of Soil and Water Conservation (SWC). The economic constraint model demonstrated that farm size, number of plots, and access to financial services influence crop residue management, crop rotation, and agroforestry adoption. Hence, a larger number of plots, a larger total farm size, and access to rural savings and credit increase the probability of adoption. The diffusion innovation model, on the other hand, asserted that frequent extension visits, market access, access to information communication, social networks, and strong tenure security have no less of an impact on the adoption of CSA innovations such as improved variety, crop residue management, crop rotation, compost, SWC, and agroforestry. Furthermore, farmers' perceived technology-specific characteristics of CSA innovations increase the likelihood of adoption. Hence, formal education, more awareness about climate change and CSA, and the ability of CSA innovations to reduce the impact of climate change risks such as rising temperatures, increased hailstorms, and increased erratic rainfall have significantly increased the likelihood of adoption. The integrated technology adoption model explains the determinants of adopting multiple CSA innovations simultaneously. Livelihood asset building programs, strong public extension systems via mobile phone, voice messaging, and radio enhance adoption. Policy to identify and scale up a portfolio of farm-level specific CSA innovations is required.

SOIL EROSION ASSESSMENT WITH INVEST MODEL: CASE STUDY IN WEE-OYA WATERSHED IN SRI LANKA

Human-induced soil erosion is one of the most significant types of land degradation in the Wee Oya watershed in Sri Lanka. The high intensity of rainfall, steep slopes, and inappropriate land use practices are strongly associated with soil erosion in the area. The prime aim of the study was to estimate soil erosion in the watershed and its seven sub-watersheds using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST), Sediment Delivery Ratio (SDR) model. Furthermore, a comprehensive household (HH) questionnaire survey (n=30) was conducted to ascertain key socio-economic information such as the farmer’s age, gender, education level, the extent of land for cultivation, and the degree of practicing soil and water conservation (SWC) measures. Then, the multiple regression analysis was applied to determine the significant socio-economic determinants of erosion in the watershed. The results of the assessment disclosed that the present average annual rate of human-induced soil erosion of the watershed is 167 t/ha/yr. Moreover, the most significant (p<0.05) socio-economic determinants of the soil erosion of the study area are the farmer’s age and family size. Furthermore, the study revealed that more than 50% of the farmers do have not a substantial perception of existing government policies’ implications concerning human-induced soil erosion. Finally, the outcome of the assessment has highlighted the necessity of human intervention for effective SWC measures in the study area.

Impact Assessment of Soil and Water Conservation Measures on Carbon Sequestration: A Case Study for the Tropical Watershed Using Advanced Geospatial Techniques

A sustainable method for protecting natural resources is the adoption of recommended soil and water conservation (SWC) measures. SWC measures are well recognized for their effective soil protection and water harvesting. Unfortunately, their significance in climate change mitigation has yet to receive global attention. The present study was conducted to highlight the applicability of SWC measures for carbon management in watersheds. In this study, the impact of SWC measures on land cover, soil erosion, carbon loss, and carbon sequestration were investigated using advanced techniques of remote sensing (RS) and geographic information systems (GIS). The study was conducted in the Central Mahatma Phule Krishi Vidyapeeth (MPKV) campus watershed, located in the rainfed region of Maharashtra, India. The watershed is already treated with various scientifically planned SWC measures. Following the implementation of conservation measures in the watershed, average annual soil loss was reduced from 18.68 to 9.41 t ha−1yr−1 and carbon loss was reduced from 348.71 to 205.52 kgC ha−1yr−1. It was found that deep continuous contour trenches (DCCT) constructed on barren, forest, and horticultural land have the soil carbon sequestration rates of 0.237, 0.723, and 0.594 t C ha−1yr−1, respectively, for 0–30 cm depth of soil. Similarly, compartment bunds constructed on agricultural land have a soil carbon sequestration rate of 0.612 t C ha−1yr−1. These findings can be of great importance in the planning and management of climate-resilient watersheds.

Evaluating Biophysical Conservation Practices with Dynamic Land Use and Land Cover in the Highlands of Ethiopia

Ethiopia is one of the sub-Saharan countries affected by land degradation, notably by soil erosion. The government of Ethiopia has launched an extensive biophysical soil and water conservation (SWC) effort each year to address the problem. These practices were installed on varying land use and land cover (LULC) systems. Despite the fact that the interventions covered the majority of the landmasses, there were no quantitative data on the scale of biophysical measures with the change in land use and land cover. Therefore, the objective of this study was to evaluate biophysical conservation practices with dynamic land use and land cover in the highlands of Ethiopia. The study focused on districts of the Amhara regional state’s South Gondar zone. A mixed research methodology was employed to gather pertinent data for the study. The dynamics of LULC were analyzed using satellite images acquired between 1990 and 2020. Biophysical conservation measures’ data and qualitative information were collected from the zonal office of agriculture. Twelve years’ worth of biophysical SWC measures data were used for the study. The results indicate that cultivated land makes up the majority of land use and land cover. Bunds built on cultivated land account for 93% of conservation practices. During the study period, there was a significant decline of biophysical conservation practices implementation in each district. Although plantation was used on a wider scale, it was unable to sustain physical SWC practices or expand forest cover in the region. In addition, lack of integrated maintenance for early installed structures decreases the effectiveness of SWC measures. In conclusion, the dynamics of LULC have a significant impact on the magnitude of biophysical conservation measures. Therefore, watershed managers shall consider the spatio-temporal variation of LULC while planning conservation practices.

Do agricultural extension services promote adoption of soil and water conservation practices? Evidence from Northern Ghana

Agricultural environment in many developing economies has become increasingly unpredictable in recent decades as a result of climate change, increasing the risk of crop failure. Access to meaningful information is required to mitigate the negative effects of the changing environment. This study examined the impact of agricultural extension services on the adoption of soil and water conservation (SWC) practices using data obtained from farming households in Northern Ghana. A multivariate probit model was used to assess the simultaneous or/and substitution adoption of SWC practices, while endogenous switching probit (ESP) was used to estimate the impact of extension services on adoption of SWC practices to account for observed and unobserved heterogeneities. The results showed that most of the SWC practices were adopted jointly, and factors such as non-farm economic activites and farm size influence the adoption of SWC practices. Moreover, farmers who accessed agricultural extension services had a higher probability of adopting most of the SWC practices (crop rotation, contour ploughing and manure application), and those who did not benefit from extension services would have had an equally higher likelihood of adopting the SWC practices had they accessed the services. The findings of the study imply that enhancing agricultural extension services will reduce adoption gaps in SWC practices, and consequently reduce farmers’ exposure to climate-related agricultural production risks. With growing information and communication technologies, pluralistic extension service delivery that mixes governmental and private-sector-led approaches to extension operations to foster demand-driven extension delivery services are highly recommended.

Effects of soil and water conservation measures on sediment delivery processes in a hilly and gully watershed

China has implemented a series of ambitious soil and water conservation (SWC) projects on the Chinese Loess Plateau, which have significantly changed the erosion, transport, and deposition of sediment. As a result, the sediment flux of the Yellow River, once the largest carrier of fluvial sediment worldwide, has been reduced by approximately 85 % in the past 60 years. However, the effects of SWC measures on erosion, transport, and deposition of sediment are still difficult to quantify, which greatly limits the further planning and adjustment of SWC measures. Here, we determined soil erosion, sediment deposition, and sediment yield at different historical stages in a 187 km2 hilly and gully watershed on the Chinese Loess Plateau using the unmanned aerial vehicle (UAV) photogrammetry technology combined with check dam surveying and hydrologic monitoring. The results show that the construction of check dams and vegetation restoration significantly reduced the soil erosion rate, from 21,144 t km−2 yr−1 at Stage-1 (1960–1969) to 13,819 ± 3,622 t km−2 yr−1 at Stage-2 (1970–1999) and further to 4,723 ± 1,278 t km−2 yr−1 at Stage-3 (2000–2018). The sediment deposition rate was estimated to be 5,989 and 2,582 ± 351 t km−2 yr−1 at Stage-2 and Stage-3, respectively. The variation in the erosion and deposition of sediment led to a significant change in the sediment delivery ratio, from 1 at Stage-1 to 0.57 at Stage-2 and 0.45 at Stage-3. Our research results provide an important reference for further SWC planning.

Farmer-science-based soil degradation metrics guide prioritization of catchment-tailored control measures

Locally valid and up-to-date soil degradation surveys that account for the spatial variability and the dynamic nature of degradation processes within environmentally diverse catchments are scant. Failure to understand local priorities and involve land users in the assessment of soil degradation and restoration initiatives however might compromise the adoption of effective soil and water conservation (SWC) measures. This paper presents farmer-science-based metrics (FSBM) of soil degradation status for locally perceived degradation processes, thereby using socio-economically relevant criteria and permitting a standardized comparison of their status across various decision-making entities. The approach was tested in the low-, mid-and highland agro-ecological zones (AEZs) in two catchments of the Lake Abaya-Chamo Basin, Ethiopia. After defining land users' relevant classes of land degradation degree, extent and impact, the soil degradation status perceived by 384 household heads was collected during face-to-face interviews. The respondents' evaluation of soil degradation status was translated into numerical scores (FSBM) and shown on radar diagrams, stratified by AEZ and catchment. Our findings demonstrate that the adopted FSBM offered spatially explicit information on the three dimensions of degradation status by soil degradation type. Disentangling degree, extent and impact revealed the diversified occurrence of the soil degradation processes between and within similar AEZs of the catchments. Natural and human factors were pinpointed as causes, while assessment of consequences revealed spill-over effects of soil erosion taking place in midland AEZs into the lowlands. Biophysical aspects, socio-economic characteristics and proximity to training centers played significant roles in the respondents’ perceptions. Despite the subjectivity associated with FSBM, our findings demonstrate that involving land users in the assessment of soil degradation provided a comprehensive overview of soil degradation status and current bottlenecks in its combat.

Land use, management and climate effects on runoff and soil loss responses in the highlands of Ethiopia

Soil erosion by water is a major cause of land degradation in the highlands of Ethiopia and anywhere else in the world, but its magnitude and variability are rarely documented across land uses and climatological conditions. The purpose of this study was to examine runoff and soil loss responses under cropland (CL) and grazing land (GL) management practices in three climatic regions of the Ethiopian highlands: semi-arid (Mayleba), dry sub-humid (Gumara), and humid (Guder). We measured runoff and soil loss using runoff plots with and without soil and water conservation (SWC) measures (trenches, stone/soil bunds [embankments] with trenches on the upslope side, and exclosure) during the rainy season (July–September). The results revealed significant variation in runoff and soil loss amounts across land uses, SWC measures, and climatic regions. At Mayleba, seasonal runoff and soil loss in control plot were far higher from GL (280 mm, 26.5 t ha−1) than from CL (108 mm, 7.0 t ha−1) largely due to lack of protective vegetation cover and soil disruption because of intense grazing. In contrast, at Gumara and Guder, seasonal soil loss values were much higher from CL (21.4–71.2 t ha−1) than from GL (0.6–24.2 t ha−1) irrespective of runoff values. This was attributed to the excessive tillage/weeding operations involved in cultivation of teff (cereal crop) at Gumara and potato at Guder. Although SWC measures (practices) substantially reduced runoff and soil loss (decreased by 23%–86%) relative to control plot, seasonal soil loss under GL uses with trenches at Mayleba (12.6 t ha−1), CL with soil bunds and trenches at Gumara (22.1 t ha−1), and Guder (21.4 t ha−1) remained higher than the average tolerable soil loss rate (10 t ha−1 year−1) proposed for the Ethiopian highlands. This suggests that SWC measures should be carefully designed and evaluated specific to land use and climatic conditions. Overall, the results of this study can help improve SWC planning in regions where land use and climate impact on soil erosion vary across geographical areas, as they do in Ethiopia and anywhere else. However, further investigation is crucial with replication of measurements over years and locations to provide more accurate information on land use, management and climate controls on hydrological and soil erosion processes.

The impact of land certification and risk preferences on investment in soil and water conservation: Evidence from southern Ethiopia

This paper evaluates the impact of land certification and risk preferences on the adoption of different soil and water conservation (SWC) technologies using survey data at plot and household level from Ethiopia. Both long-term and short-term investments are considered. Using multivariate probit and correlated random-effect Poisson regression models, we find a heterogeneous impact of land certification on the adoption of SWC techniques among farmers with different risk profiles. We find that certification enhances land investment and that the effect is stronger for more risk-averse farmers. Land certification has a positive effect on the adoption of SWC techniques with a longer payback period such as biological and physical practices, but only for high risk-averse farmers. For short-term investments in SWC techniques like agronomic practices, which are used less to claim the land but with considerable productivity effects, the land certification has a positive effect for both low and high risk-averse farmers, but more strongly for the latter. Hence, our findings suggest that land certification programs could have an important contribution to breaking the risk-induced low technology uptake - agricultural development trap by motivating (particularly risk-averse) farmers to enhance their land investments.

Soil and Water Conservation in Africa: State of Play and Potential Role in Tackling Soil Degradation and Building Soil Health in Agricultural Lands

Africa’s lands are largely vulnerable and threatened by soil degradation and low water availability, especially in semi-arid and arid regions, limiting crop and livestock productivity and farmer livelihood options. Therefore, in African agricultural lands, adopting/improving measures that conserve soil and water resources is crucial. This review aims to provide an update on soil and water conservation (SWC) in terms of farmer practices and research actions and explore how SWC technologies and practices represent a pathway to build or re-establish soil health and enhance sustainable agriculture in Africa. It also aims to increase knowledge on best-fit SWC approaches. Soil conservation, which includes measures of controlling soil erosion and maintaining or improving soil fertility, is inseparable from water conservation. On agricultural lands, the two are typically co-addressed. Increasing plant biomass production through improved water, crop and soil management practices, and managing this biomass judiciously, have direct and indirect impacts on conserving soils and water resources, particularly in drylands. This study focuses on rainfed agricultural systems. We discuss the barriers and challenges to scaling up best-bet SWC technological and management options. Moreover, we show that options, such as Conservation Agriculture (CA), Agroforestry (AF), as well as integrated soil fertility management (ISFM) and field-scale rainwater harvesting (RWH), remain promising for the preservation and improvement of soil health in Africa’s farmlands and improving the resilience of agrosystems to climate change and variability as well as droughts.

Analysis on process management of soil and water conservation design for transmission line projects in Qinghai Province

The first part is a brief introduction of soil and water conservation (SWC) and loss condition of transmission line projects and in Qinghai Province；In the second part, based on the Qinghai Yuqia-Toesu 750 kV line project, and combined the experience and methods concluded during the soil and water conservation (SWC) design work, the process management for SWC design in Qinghai’s transmission line projects is analyzed; The third part is the conclusion and the suggestion. Through the introduction and analysis of the three parts, the thinking pattern of SWC design of transmission lines in Qinghai Province are clearer, which can be a reference for Qinghai’ SWC designer.

Analysis on process management of soil and water conservation design for transmission line projects in Qinghai Province

The first part is a brief introduction of soil and water conservation (SWC) and loss condition of transmission line projects and in Qinghai Province；In the second part, based on the Qinghai Yuqia-Toesu 750 kV line project, and combined the experience and methods concluded during the soil and water conservation (SWC) design work, the process management for SWC design in Qinghai’s transmission line projects is analyzed; The third part is the conclusion and the suggestion. Through the introduction and analysis of the three parts, the thinking pattern of SWC design of transmission lines in Qinghai Province are clearer, which can be a reference for Qinghai’ SWC designer.

Contributions of integrated soil fertility management (ISFM) to various sustainable intensification impact domains in Tanzania

CONTEXTThe implementation of integrated soil fertility management (ISFM) varies widely among farmers, from no ISFM to multiple computations of ISFM components (i.e., improved germplasm, organic resources, fertilizers, and local adaptations e.g., soil and water conservation (SWC)). There is no comprehensive report on farmers' use of ISFM components and their impact on sustainable intensification domains of productivity, economic, social, human condition, and environment and the associated variations across farmer fields and agro-ecological zones (AEZs). OBJECTIVEThis study 1) evaluated the current implementation status of ISFM by farmers in relation to the various ISFM components and 2) provided multi-dimensional multi-scale evidence of ISFM implications that can guide ISFM investments within SSA contexts, with a specific focus on Tanzania. METHODSWe used data collected from 1406 plots between 2013 and 2020 in semi-arid and sub-humid AEZs. The data are from farmer practices. The plots were grouped by the various combinations of ISFM components implemented and analysed using Tukey's test to examine the association of ISFM use with selected indicators within a domain. RESULTS AND CONCLUSIONSThe number of ISFM components used by farmers is higher in sub-humid (1 to 4) than in semi-arid AEZ (0 to 3). Except for SWC used by 40% of farmers in both AEZs, the proportion of farmers using improved seeds (95%) and manure (55%) in the sub-humid AEZ are more than double those using these ISFM components in the semi-arid AEZ. Productivity and economic benefits increase with the number of ISFM components at the expense of higher labour demand. Increasing plot-level ISFM benefits also translate to increased household-level whole-farm income but contributions to human nutrition are unclear. The contribution to SOC by increasing ISFM is insignificant, compounded by strong effects of slope position of the field. Differential access to resources, decision-making and control rights drive the number and choice of the specific ISFM components. SIGNIFICANCEUnderstanding of ISFM impacts across domains is essential to guide the scaling of ISFM in Tanzania and beyond and therefore recommended in future studies.

Impact of Soil and Water Conservation on Household Income in West Arsi Zone of Oromia

Land degradation due to soil erosion and nutrient depletion is one of the main problems constraining the development of the agricultural sector in Ethiopia. As part of intervention activities number of soil and water conservation (SWC) practices have been promoted to smallholder farmers living in highly degraded and drought prone areas of the country. This study was conducted to assess the impact of SWC intervention on the livelihood of smallholder farm households in terms household income and productivity. To meet this objective primary data was gathered from 150 sample responds (67 SWC program participants and 83 non-participants). Descriptive and inferential statistics and propensity score matching (PSM) models were used to address the stated objectives. Results of the descriptive statistics showed that before matching there was statistically significant difference between program participants and their counterfactual households in terms of sex, education and farm experience generally in favor of non-program participants whereas access to market information and amount of land allocated for production in favor of program participant in the zone. The analysis of mean difference in outcome variables before matching result indicated that the mean total crop yield for SWC practiced respondent households is higher (22.102quintal per hectare per household) than SWC non-practiced respondent households (17.26quintal per hectare per household) with mean total crop yield difference equivalent to 4.842 quintal per hectare per household in the zone. In the mean-time, even though, the results of the PSM model revealed that SWC intervention did not result in significant difference between program participant and non-participant households in terms of maize productivity and gross crop income total annual crop income of households who participated in SWC program was 10,838.13 birr whereas its 6075.48 birr for non-participant farmers accounting 4762.65birr difference suggesting that on average participant households earned 43.9 percent more crop value per hectare than the control group. Logistic regression model was employed to estimate propensity scores for matching SWC program households with their counterfactuals. Except sex of the household, Market information, amount of land cultivated, Education and farm experience influenced the probability of HH participation in SWC positively and significantly at 10% expect land cultivated at 5% level. The implication could be that farm household participation was more guided by demographic than economics factors (defined by farm size and herd size). Nominal results of analysis of treatment effects indicate that there was a sign of positive impact on both of the variables considered due to SWC program. However, the changes in crop productivity and gross household income could not be statistically justified as there was no statistically significant difference between the two groups in terms of these variables. The possible reason could be that SWC programs are not short-term nature and impacts are to be realized gradually with increased adoption and intensification of activities. Finally it was to be noted that there were positive trends which all together should guide SWC policy makers to identify important factors influencing the contribution of such a program and reconsider the design and implementation of the interventions. Keywords: Impacts, Income, participant, non- participant, household, Propensity Score Matching. DOI: 10.7176/JBAH/12-18-01 Publication date: September 30 th 2022

Community-Based Watershed Development Processes and Extent of Community Participation in the Northwestern Highlands of Ethiopia

This study describes processes followed and involvement of community members in implementation of community-based watershed development (CBWD) projects in three micro-watersheds (Adef Wuha, Guansa and Tija Baji) in northwest Ethiopia. Data was collected through household survey from systematically selected 114 household heads that possessed farmlands in the study watersheds. Focus group discussion and key informant interviews were also conducted to collect supplementary qualitative information. Participation index (PI) was used to measure the extent of community participation in the different activities of watershed development. The results showed that the extent of community participation could be rated as moderate, with a PI score of about 63%. The communities had actively participated in the selection of members of Community Watershed Planning Teams (CWPT) and in discussions on watershed development plans subsequently developed, identifying problems and prioritizing local needs and in preparations of conservation bylaws. They also actively participated in the implementation of physical soil and water conservation (SWC) (terraces, cutoff drains, water ways, check-dams, hand-dug well and spring development) and biological measures (afforestation, planting trees and grasses, and nursery development). The households received food and hand tools (e.g. spade) in return for their participation. Dependency to food and material support, high expert turnover, low level and partiality of bylaws implementation, shortage of grazing land and fuel wood were the main challenges that affect the sustainability of the watershed development outcomes. In other words, these should be addressed to ensure sustainability of the achievements. Keywords: Land degradation; community watershed conservation; participation index; Ethiopia DOI: 10.7176/JRDM/87-02 Publication date: September 30 th 2022

Climate Change Effect on Water Use Efficiency under Selected Soil and Water Conservation Practices in the Ruzizi Catchment, Eastern D.R. Congo

Concerns have been raised on the effectiveness and sustainability of Soil and Water Conservation (SWC) practices as adaptation options to climate change and high intra– and inter–annual rainfall variabilities in eastern Democratic Republic of Congo (DRC). This study was conducted in the Ruzizi Plain, a dryland area, to assess the performance of maize (Zea mays L.) under two Representative Concentration Pathways (RCP 4.5 and 8.5) and two SWC practices (tied ridges and conventional tillage). The AgMIP’s Regional Integrated Assessment (RIA) approach was used to simulate Water Use Efficiency (WUE) under the Cropping System Model–Crop Environment Resource Synthesis (CSM–CERES–Maize) of the Decision Support System for Agro–technology Transfer (DSSAT). The model was calibrated using experimental data from nine cropping seasons (2011–2018) and 100 farms. The model sensitivity was assessed as a function of temperature, water, and SWC practices for the same environments. Initial conditions of crop management practices were used as input data for CSM–CERES–Maize. Current climate data were extracted from AgMERRA datasets corrected with local data for the period of 1980 to 2021. Future climate projections (2022–2099) were obtained after down−scaling the data from the 29 General Circulation Models (GCMS) of Coupled Model Intercomparison Project 5 (CMIP5) and subsetted to five GCMs based on climate regimes. GCMS results were a strong indicator that climate change in this DRC dryland will result in an increase in average annual temperatures for both RCP 4.5 and 8.5, with the highest increase (3.05 °C) under hot/dry conditions for RCP8.5 and the lowest (1.04 °C) under cool/dry conditions for RCP 4.5. All the models selected for five climate regimes for 2022–2099 showed no change in the rainfall trends for RCP 4.5 (p > 0.05). The models projected yield declines of 5–25%, with less yield losses under tied ridges as an adaptation practice. The use of efficient SWC practices could therefore be a promising strategy in reducing potential losses from climate change in drylands of eastern DRC.

Assessing soil system changes under climate-smart agriculture via farmers' observations and conventional soil testing.

Soil degradation remains a challenge in African highlands, where land management lacks a strong context‐specific evidence base. We investigated the impacts of recently implemented soil and water conservation (SWC) practices—farmyard manure addition, incorporation of crop residues in soil and fanya juu terracing under an agroforestry system on soil health indicators in the East Usambara Mountains of Tanzania. Farmers' observations of soil changes were combined with conventional soil testing to assess the initial impacts of SWC practices relative to conventional non‐SWC practice. Majority of farmers (66%–83%) reported that combining fanya juu terracing with organic amendments led to soil colour change from red to black and an increase in crop yield. Despite the observed darkening of the soil, there was no significant increase in soil organic carbon stock and the contents of N, P, K. There were important changes in soil physical properties, including greater aggregate stability (mean weight diameter of 1.51–1.71 mm) in the SWC plots, a greater volume of transmission pores (>60 μm) and coarse storage pores (10–60 μm) in the surface soil layer (0–15 cm), and greater volume of fine storage pores (0.2–10 μm) and residual pores (0.2 μm) in the sub‐surface layer (15–30 cm) of the SWC plots compared with the conventional plots. These changes indicate that SWC rapidly enhances infiltration and retention of water within the root zone, which are important for increasing crop yields and improving the resilience of the agro‐ecosystem to environmental stress. Combining SWC with effective soil fertility management is needed for sustainable highland agriculture.

Soil Bunds Effect on Soil Properties under Different Topographies of Southwest Ethiopia

Soil erosion is a major environmental problem affecting development endeavors. Physical soil and water conservation (SWC) measures such as soil bunds are implemented to mitigate soil erosion. However, information on the effects of soil bunds on soil fertility is limited. This study aimed to evaluate soil quality in fields with soil bunds and with no soil bunds in steep, middle and lower sloping cultivated lands as well as spatial variation of soil properties in between bunds in southwest Ethiopia. About 7-15 years old bunds and nearby cultivated fields lacking bunds were assessed. From 0 cm-20 cm soil depth, 36 soil samples were collected. Soil texture, soil organic carbon (SOC), total nitrogen (Ntot) and exchangeable potassium (Kexch) were analyzed. Soil bunds showed significantly (p<0.0.5) greater clay but less sand than adjacent no-bund fields. In steep, middle, and lower slopes, concentrations of SOC and Kexch were greater in fields with soil bunds than without. Lower slope fields showed greater clay, SOC and nutrients than steep slopes. In between soil bunds, soil was more fertile at bunds than below the bunds. In Fanta watershed, soil bunds are a vital conservation measure to retain soil fertility in cultivated mountainous areas.

Ecosystem Service Assessment of Soil and Water Conservation Based on Scenario Analysis in a Hilly Red-Soil Catchment of Southern China

Soil and water conservation (SWC) practices on agricultural watersheds have been the most effective practices for preventing soil erosion for several decades. The ecosystem services (ES) protected or enhanced by SWC practices include the comprehensive effects of protecting and conserving water sources, protecting and improving soil, carbon fixation, increasing agricultural production, and so on. Due to the lack of ES evaluation indicators and unified calculation methods in line with regional characteristics, this study proposes a framework of scenario analysis by using ES mapping, ES scoring, and economic analysis technology for ES and economic-benefit trade-offs under different scenarios. The study area was the Xiaoyang catchment located in Ningdu County, Jiangxi Province, which is a typically hilly red-soil region of southern China. From the results of scenario analysis, an obvious phenomenon is that some SWC practices can affect the value of some ES indicators, while some have no clear trend. By computing the ES scores for the four scenarios, the ranking was S3 (balanced), S1 (conservation), S2 (economic), and S0 (baseline). S3 ranks second in net income (with CNY 4.73 million), preceded only by S2 (CNY 6.36 million). Based on the above rankings, S3 is the relatively optimal scenario in this study. The contributions of this study are the method innovation with the localization or customized selection of ES indicators, and scenario analysis with ES scores and economic-benefit trade-offs in different scenarios.