Definition Of Soil And Water Conservation Pdf
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- Soil and Water Conservation Engineering, Seventh Edition
- Soil and Water Conservation Measures for Agricultural Sustainability
- Soil conservation
Soil Conservation is a combination of practices used to protect the soil from degradation. First and foremost, soil conservation involves treating the soil as a living ecosystem. This means returning organic matter to the soil on a continual basis. Soil conservation can be compared to preventive maintenance on a car.
Though soil and water conservation SWC technologies have been adopted in Geshy subcatchment, their effects on soil quality were limitedly studied. The studied soils are characterized by low bulk density, slightly acidic with clay and clay loam texture.
P at the bottom slope classes and terrace positions could be attributed to the erosion reduction and deposition effects of SWC measures. P deficient. Thus, integral use of both physical and biological SWC options and agronomic interventions would have paramount importance in improving soil quality for better agricultural production and productivity. Soil degradation, which involves physical, chemical, and biological degradation, is the key component of land degradation [ 2 , 3 , 4 ].
The most critical forms of soil degradation are depletion of soil quality and soil erosion by water [ 5 ]. Thus, SQ indicators can be defined as those soil properties and processes that have greatest sensitivity to changes in soil function due to the change in land management practices on a short-term bases [ 7 ]. Hence, SQ assessments are the quantification of SQ indicators and are the measurable soil property that affects the capacity of a soil to perform a specified function [ 8 ].
The problems of soil degradation and low agricultural productivity are severe in the rural highlands of Ethiopia [ 9 , 10 ]. SQ deteriorations in the country are mainly caused by water erosion due to rugged topography, mismanagement of land resources, and loss of vegetation cover [ 11 ].
In Shomba subcatchment, Mekuria [ 12 ] also reported that the estimated mean annual rate of soil erosion in cultivated fields was The governmental and nongovernmental institutions have been investing huge financial and labor resources to tackle land degradation in Geshy subcatchment, Gojeb River Catchment of Ethiopia. Various soil and water conservation SWC technologies have been adopted and constructed in cultivated fields and the afforestation of hillsides by sustainable land management program SLMP under Ministry of Agriculture.
Improved land management practices like SWC have been suggested as a key strategy to reduce land degradation and sustain soil quality [ 17 , 18 ]. Though the prime aims of SWC interventions were to reduce soil erosion, restore soil quality, and enhance agricultural productivity, there are mixed and contradicting reports about its benefits implemented in Ethiopia.
Several studies e. Other studies in various parts of Ethiopia [ 3 , 17 , 21 , 22 , 23 ] reported that SWC technologies have played a significant role in maintaining soil quality, enhancing agricultural production and mitigating land degradation. Contrarily, Wolka et al. Thus, proper understanding and quantifying changes in soil quality resulting from SWC interventions is imperative, as it provides information on the effectiveness of diverse land management options.
Effects of SWC interventions on soil quality are inherently site-specific, and no study has been conducted to evaluate its effects on soil quality in Geshy subcatchment. There is an urgent need to assess the effects of SWC measures on soil quality indicators. Therefore, the objective of this study was to assess the effects of SWC technologies on soil quality indicators in Geshy subcatchment of Gojeb River Catchment, Ethiopia.
The study was conducted in Geshy subcatchment of Gojeb river catchment, Ethiopia, which covers a total area of Thus, small tributaries along with the main stream, Geshy river, are from west, south-west, south, and south-east of Geshy river that flows to Gojeb river at its outlet Figure 1. Based on records in Gojeb meteorological station, the coolest months are June to August in the middle of the main rainy season, while the hottest months are from February to May.
The rainfall is unimodal with low rainfall from November to February and the wettest months between May and September. In the Geshy subcatchment, according to FAO soil classification, the soil mapping units are dominantly of Humic Nitisols The land use pattern is characterized by extensive cropland and mainly dominated by five LULC classes such as cropland, forest land, shrublands, woodland, and swamp area Table 1.
The total population is from which are men with total number of households [ 12 ]. A preliminary survey was conducted in one of the SLMP implementing sites, Geshy subcatchment to identify appropriate sites for sampling plots. Hence, soil data were collected from farmlands with and without SWC measures and made comparison between these treatments at various slope classes and positions within the terraces.
In the case of farm plots with SWC measures, the sampling plots refer to the area between the two successive terraces. In the case of farmlands without SWC measures, the sampling plots refer to the area under cultivation, which is found between successive farm boundaries.
Then, the selected subcatchment was classified into different slope categories using a digital elevation model DEM. The DEM output and the subcatchment soil map were used to classify the study area and to identify sampling plots. In Geshy subcatchment, a reconnaissance survey was conducted to determine the representative SWC measures and soils sampling plots.
Different soil sampling methods have their own advantages and a drawback. Landon [ 28 ] suggests judgment sampling for selection of typical sites is feasible to represent large areas.
Furthermore, sample sites were characterized following the approaches used by Shiene [ 23 ], Winowiecki [ 29 ], Abegaz et al. Accordingly, judgment sampling was used to take representative soil samples from farmlands with and without SWC measures. In the study subcatchment, all soil samples were taken from similar soil mapping units, Humic Nitisols, to see the effects of SWC measures on soil quality indicators.
A portable global positioning system GPS was used to record the longitudes, latitudes, and altitudes of sampling points Figure 3. The slope classes, the soil mapping units, and soil sampling points are shown in Figure 3 below. Moreover, three sampling positions within the terraces of the fixed plots were selected, i. The reason for selecting these three slope positions is that soils and their drainage conditions vary considerably over such areas.
Furthermore, the Soil Conservation Research Programme SCRP did long-term series of productivity measurements using the same procedure, which can be used for comparing soil quality with agricultural production in these positions [ 25 , 31 ]. Soil sampling was done from three slope categories and in three terrace positions with three replications plots Figure 3 , Table 2. Thus, a total of 54 soil samples were collected for soil laboratory analysis from January to February Undisturbed soil samples were collected using a core ring sampler for the determination of dry bulk density and soil water content at the center of sampling plot.
Thus, a total of 54 samples 27 samples from farm plots with SWC measures and 27 from farm plots without SWC measures were collected for laboratory analysis. The farmlands with and without SWC measures, slope, and terrace positions were used as independent variables factors and the soil quality indicators as the dependent variables.
The selected soil quality indicators considered in this study were particle size distributions, dry bulk density, volumetric soil water contents, total porosity, pH, soil organic carbon SOC , total nitrogen TN , carbon-to-nitrogen ratio, and available phosphorus AP. Total porosity was estimated from bulk density and particle density assuming particle density of 2. Soil reaction pH and particle size distribution were determined using The available phosphorus AP was determined following the Olsen procedure [ 38 ].
All data on soil quality indicators were tested for normality prior to doing the analysis of variance. Moreover, the map of spatial variability of particle size distributions and bulk density was shown in Figure 4 below. The soil particle size distribution in both with and without SWC treatment is shown in Table 3 and Figure 4. The analysis of variance ANOVA showed that, unlike sand fractions, silt and clay fractions were significantly varied with treatments Table 6.
Though not statistically significant, relatively higher sand fractions were recorded in soils treated with SWC than without SWC measures. However, in the farmlands with SWC, the overall average values of silt and clay fractions showed significant variation , but sand did not show significant variation within the terrace position Table 3.
Accordingly, the overall average clay fractions in the lower The overall average silt fractions in the lower However, in the farmlands without SWC measures, the overall average sand, silt, and clay fractions did not show any significant variation within terrace positions Table 3.
This could be attributed to the effect of SWC measures on soil erosion and deposition processes. The PSD did not follow any distinct pattern across the slope positions both in the farmlands with and without SWC measures. Inline with this finding, Wolka et al. Similarly, Mengistu et al. Moreover, Hailu et al. In Geshy subcatchment, the spatial distribution of bulk density was shown in Figure 4. The bulk density did not show any significant variations with treatments, slope classes, and positions within the terraces as well as their interactions effects Table 6.
The soil are found within the critical level 1. Similarly, Hailu et al. Conversely, they reported a significant variation of with landscape positions.
Shiene [ 23 ] also did not observe a significant difference in across landscape positions in the Wello area. In contrast, Demelash and Stahr [ 39 ], and Abay et al. In contrast, Shiene [ 23 ] reported significant variation of at the three terrace positions. Thus, the nonsignificant differences observed in soil physical quality indicators between farmlands with and without SWC measures may be related to the age of SWC structures.
The overall VSWC was significantly varied with treatments and positions within the terraces , but not significantly varied with slope classes and their interaction effects of treatments, terrace positions, and slope classes , Table 6.
In farmlands without SWC measures, it did not show any significant variation with slope positions , Table 3 , which could be attributed to absence of SWC structures to trap sediment and store moisture. In respect to positions within the terrace, the VSWC showed significant variation , Table 3 among lower, middle, and upper terrace positions. Accordingly, the significantly highest VSWC was observed in the lower terrace position However, it was significantly higher in the lower The overall average VSWC was found to be significantly higher in the lower terrace positions , This could be attributed to the presence of significantly higher OM, clay soils, and the effect of SWC in reducing runoff velocity and enhanced infiltration than the faster runoff flow down the slope for farmlands without SWC measures.
To put it in a nutshell, in the study subcatchment, the average VSWC in the farmlands with SWC measures have been found to be higher , Numerically, it is almost similar in both farmlands with and without SWC treatments, which might be attributed to the age of structures and insignificant variation of bulk density with treatments.
Similarly, other studies [ 23 , 41 ] revealed that terraces in the lower slope areas have gentler slopes and wider spacing, and as a result, the incoming runoff could remain for longer period and partly deposit suspended and dissolved materials. Soil pH, which affects nutrient availability and toxicity, microbial activity, and root growth, is the first parameter to be considered in soil quality evaluation [ 42 ].
In the Geshy subcatchment, the spatial distribution of soil pH was shown in Figure 5. The ANOVA indicated that soil pH is significantly varied with treatments, but not with slope classes and positions within the terrace as well as their interaction effects , Table 6.
Variations in soil pH among slope classes were not statistically significant , Table 6. In farmlands with SWC measures, soil pH value showed a decreasing trend with increasing slope classes Table 5. Moreover, soil pH did not show any significant variations with terrace positions , Table 5. However, its value was found to be higher in the lower deposition zone than the upper loss zone in farmlands with SWC measures Table 5 , which may be attributed to the positive effect of SWC practices to increase the pH of the soil and then reduces soil acidity.
Amare et al. Wolka et al. Studies elsewhere [ 3 , 22 , 39 ] and [ 41 ] revealed no significant differences in pH of soils between conserved and nonconserved lands.
Soil and Water Conservation Engineering, Seventh Edition
Soil conservation is the prevention of loss of the top most layer of the soil from erosion or prevention of reduced fertility caused by over usage, acidification , salinization or other chemical soil contamination. Slash-and-burn and other unsustainable methods of subsistence farming are practiced in some lesser developed areas. A sequel to the deforestation is typically large scale erosion , loss of soil nutrients and sometimes total desertification. Techniques for improved soil conservation include crop rotation , cover crops , conservation tillage and planted windbreaks , affect both erosion and fertility. When plants die, they decay and become part of the soil.
Though soil and water conservation SWC technologies have been adopted in Geshy subcatchment, their effects on soil quality were limitedly studied. The studied soils are characterized by low bulk density, slightly acidic with clay and clay loam texture. P at the bottom slope classes and terrace positions could be attributed to the erosion reduction and deposition effects of SWC measures. P deficient. Thus, integral use of both physical and biological SWC options and agronomic interventions would have paramount importance in improving soil quality for better agricultural production and productivity.
Soil and Water Conservation Measures for Agricultural Sustainability
Soil erosion risk assessment is an essential foundation for the planning and implementation of soil and water conservation projects. The commonality among existing studies is that they considered different indicators e. It is widely accepted that the vegetation and distribution of rainfall differs according to the different slope aspects such as sunny slope and shady slope and these attributes will accordingly influence the soil erosion.
Creating garden beds and landscapes that have active underground ecosystem of earthworms and microorganisms that keep plants healthy can be achieved using composted soil with organic materials that include micronutrients and minerals. Applying compost also provides an aerated, non-compacted base for plant roots to thrive and to absorb water and nutrients, which is key in ensuring plant health. Healthy plants mean better wildlife habitat. Conventional lawns and many ornamental exotic plants require an exorbitant amount of clean water to stay green. Choosing native plants that are adapted to regional rainfall and soil moisture content is a great way to conserve this precious resource.
Limited natural resources are available on the planet under immense pressure due to the ever-increasing population and changing climate.
Soil conservation is an important part of conservation cropping systems. There are many benefits for producers who choose to employ soil conservation practices on-farm. Many soils in Alabama have low levels of soil organic matter due to the warm climate, coarse-textured soils and intensive farming practices historically used in the state. Rebuilding soil health is important! Soil is a natural resource we must work to conserve for future generations. Practices such as reduced tillage and cover cropping can increase organic matter and improve soil health. There are several important ways producers can improve soil health.
Soil and Water Conservation within the Watershed Management approach. Soil and water conservation are those activities at the local level which maintain or enhance the productive capacity of the land including soil, water and vegetation in areas prone to degradation through. These activities are to be selected and implemented according to the respective local conditions; i. Soil and water conservation is an integral part of Watershed Management. Although Watershed Management was formerly considered to be nearly synonymous with soil and water conservation, it goes far beyond it today, comprising a variety of further activities that attempt to improve the living conditions of the people living within the respective watershed e. Introducing soil and water conservation in the Gina River catchment may further the sustainable utilisation of natural resources for the benefit of local people as the overall goal of Watershed Management. Its success will depend on the participation of local people with their traditional knowledge.
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