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Cation exchange capacity CEC 2. The population of the world is dependent on land resource for food and other necessities. Soil and water resources conservation and management is important for the welfare of the people Lal, This, according to Angima et al.
These processes of degradation contribute to the worsening poverty and further marginalization of rural people in sub-Saharan Africa. If farmers' resource base cannot be secured and rendered more productive, the decline in rural standards of living will accelerate.
Soil and water conservation must therefore be central to strategies of agricultural and rural development in sub-Saharan Africa. On farm conservation must be linked to enhanced strategies for communal property resource management. Such links will ensure optimum returns from land resources and promote a holistic approach to sustainable environmental conservation and resource management.
Therefore, soil and water conservation in Ethiopia is not only related to improvement and conservation of the environment but also it is a key factor for sustainable development of the agriculture sector and the economy of the country at large Teklu, ; Gete, SWC measures are benefiting by reducing soil erosion and changing the soil properties for agricultural productivity. Hence, it is worthwhile to investigate the effects of SWC measures on key soil properties to evaluate the benefit of treating lands with bio-physical SWC measures.
Integration of biological SWC measures that improve soil fertility are essential on the cultivated land of the watershed. At the moist subtropical site in a highland region, soil and water conservation increased soil moisture enough to potentially cause waterlogging, which was absent at the low-rainfall sites.
Runoff responses showed high spatial variation within and between land use types, causing high variation in soil and water conservation efficiency. Our results highlight the need to understand the role of the agro-ecological environment in the success of soil and water conservation measures to control runoff and hydrological dynamics.
This understanding will support policy development to promote the adoption of suitable techniques that can be tested at other locations with similar soil, climatic, and topographic conditions Sulutan et al.
The physical properties of soils determine their adaptability to cultivation and the level of biological activity that can be supported by the soil. Soil physical properties also largely determine the soil's water and air supplying capacity to plants. Many soil physical properties change with changes in land use system and its management Tugizimana J.
Soil texture: The textural classes of top soils treated with According to Mulugeta and Karl assessment of integrated soil and water conservation practice on key soil properties shown that by using different soft wares textural classes of top soils treated with SWC measures and that of the untreated lands have differences which were confirmed through statistical analysis of the soil laboratory data. The analysis revealed a significant variation of top soil texture in percent sand, silt and clay content due to effect of SWC measures Table 1.
Soils of the non-conserved land had the highest percent clay and silt compared to the soils of the conserved one. The textural classes also have a significant variation. The majority of the sample profiles of the conserved land have a top texture of clay loam and for the untreated is clay.
Herweg and Ludi pointed out that complete removal of topsoil at the loss zone causes the subsoil-dominated by clay material to move down slope and deposited on top of the fertile accumulation. They also indicated that tillage and water erosion causes colluvium to be deposited in the lower part of fields while soil profiles are truncated in the upper part. Desta et al. Age of the bund had a significant impact on the impact on the lowering of percent clay fraction as it lowers slope gradient and reduced soil erosion and soil organic matter increased with relative soil depth change.
In general bunds play a great role in reducing the incorporation of clay-dominated soil from the subsoil to the surface soil, which resulted from removal of topsoil and exposure of the subsoil by erosion. Highest clay content in the non-conserved watershed was due to the exposure of soil by tillage to soil erosion by water ultimately exposes the subsoil, which is naturally high in clay content. Accordingly, the sand content was the lowest in the soils under HM treatment and the highest under the control.
Soil texture affects the infiltration and retention of water, soil aeration, absorption of nutrients, microbial activities, tillage and irrigation practices Foth, ; Gupta, The one way analysis of variance revealed the presence of significant difference in mean value of bulk density for the samples analyzed in this study.
The non-conserved micro-watershed was found to exhibit significantly the highest mean value of bulk density than the micro-watershed treated with SWC measures. This could be attributed to the presence of significantly higher organic matter as a result of conservation measures. In this study, the relatively lower bulk densities of 0. This implies that more roots of plants, higher organic matter and sediment are accumulated in this zone of the micro-watershed.
As the land slope decreases runoff speed also decreases, sediments and organic matter started to settle Mulugeta and Karl , Root abundance, crop stand, crop production and crop residues are better in lower slopes of the micro-watersheds compared to its upper slopes as soil depth upslope is shallow which limits plant growth due to shallow soil depth even with similar conservation measures Table 2.
The topsoil bulk densities of the sampled soils are in line with the ranges described by Rai ; Landon that is, between 0. According to Mulugeta and Karl assessment of integrated soil and water conservation practice on key soil properties shown that the significant effect of SWC measures on bulk density was observed in the lower slope of the micro-watersheds where bulk density is higher in the non-conserved land than the conserved micro-watershed.
The reason for this could be higher accumulation of soil sediments that were eroded from upslope. The upslope part of the two micro-watersheds has almost similar top soil bulk densities. Infiltration rate is the soil capacity for letting water to percolate in a given period of time. The measurement is usually done in centimetres per hour. Soils with a SWC measures have a better soil infiltration rates compared to the non-conserved one.
Inrelative terms soils with biological SWC measures have a better infiltration rate than a physical SWC measure due to the roots penetration effect and addition of soil organic matter from plant bodies through decomposition. Infiltration tests conducted confirmed that soil physical structures stabilized with vegetative measures had the highest mean value of infiltration rate compared to the other conservation measures.
The non-conserved micro-watershed had lowest mean value of infiltration rate Mulugeta and Karl , The soil organic matter content and percent clay soil separates seemed to play a role for the variation of infiltration rates.
Organic matter was positively correlated with the infiltration rate while clay percentage was negatively correlated. Landon indicated that physical SWC structures enriched with vegetative measures had better infiltration rate than lands conserved with only physical structures. Soil chemical properties are the most important among the factors that determine the nutrient supplying power of the soil to the plants and microbes.
The chemical reactions that occur in the soil affect processes leading to soil development and soil fertility build up. Minerals inherited from the soil parent materials over time release chemical elements that undergo various changes and transformations within the soil Lilienfein et al.
The variations in mean value of organic carbon Corg can be attributed to the effect of SWC measures implemented. Moreover, the age of bunds stabilized with vegetative measure have a better effect in soil organic matter accumulation. This finding agrees with the findings of Million who studied the effects of indigenous soil and stone bunds on soil productivity.
In the two sites, total nitrogen Ntotal followed the same trend as the Ctotal variation in relation to treatments.
Furthermore, Calcium Ca , Magnesium Mg and pH H2O had the same trend as well as available potassium K although the differences were not always significant. According to a study made by Bot and Benites , soil organic matter accumulation is often favoured at foot or lower slopes of hills of non-conserved lands for two reasons: 1 they are wetter than mid and upper slopes, 2 organic matter would be transported to the lowest point of the landscape with runoff and soil erosion.
The soil organic matter content has a positive correlation with the fine soil particle content of the soil that is, with the soil textural classes.
Soil texture appears to have an important impact on the amount, distribution and chemical properties of soil organic matter SOM components. The agricultural significance of soil organic matter in tropical soils is greater than that of any other property with the exception of soil moisture.
Its functions are to improve soil structure, and thereby root penetration and erosion resistance; to augment cation exchange capacity; and to act as a store of nutrients, slowly converted to forms available plants Mulugeta and Karl , Table 4 presents the mean value of sampled top soil total nitrogen content. However, physical SWC measures stabilized with nitrogen fixing plants have indicated that the total nitrogen N is much higher compared with other biological measures.
The non-conserved land had the smallest mean value of total nitrogen N. Soil reaction has a direct influence on chemical and biological soil properties and parameters.
Low productive soils and sites were associated with low pHs and corresponding low levels of exchangeable bases and organic matter.
Soil pH in a soil can be attributed to the type of parent material, extent of soil erosion or the leaching of bases as a result of climatic factors. Soil pH is an indispensable means for characterizing soil from the standpoints of nutrient availability and soil physical conditions like structure, permeability, workability etc. According to Mulugeta and Karl assessment of integrated soil and water conservation practice on key soil properties shown that soil pH is also associated with soil fertility status.
Soils with high organic matter content have a higher soil pH which favours better exchange of bases and increase availability of nutrients that are needed for the growth of plants in a given soil and ecology. The mean value of pH for the sampled soils in this study shows minor difference between the conserved and non-conserved micro-watersheds. The cation exchange capacity CEC is a measure of the number of adsorption sites per unit weight of soil at a particular pH.
CEC is affected quite dramatically by pH changes. Soils with high in organic matter or type clays have a high CEC. In contrast, soils dominated by kaolinite and hydrous oxide clays generally have a low CEC.
In many weathered tropical soils the maintenance of organic matter is critical in order to maintain the CEC at a satisfactory level. According to Mulugeta and Karl assessment of integrated soil and water conservation practice on key soil properties by using A linear regression analysis confirmed the presence of significant positive relationship between CEC and percent phosphorous P in the studied micro-watersheds were found to be significantly different between the conserved and non-conserved Table 6.
It is evident that the total available phosphorus is much higher in the conserved one. Organic sources of phosphorous are important in these areas for amending the agricultural land for a better land productivity Mulugeta and Karl , According to Han et. Soil and water conservation practices exert influences on nutrient loss by retaining runoff and reducing erosion. TN and TP losses under different soil and water conservation practices are shown in Figure 5.
Existing literature and information shows that soil and water conservation practices such as terraces, mulching, cover crops, tree planting along contours can considerably reduce soil loss due to water erosion if they are well planned, correctly constructed and properly maintained Taddese, ; Mekonen and Tesfahunegn, If not maintained, they can provoke land degradation. Rsearch result shown that its representativeness with respect to intensive SWC practices such as stone bunds, hillside and bench terraces, trenches, gabion check dams and exclosure with enrichment of plantations have been carried out.
SWC interventions have been started before 15 years ago in this watershed Tigray, Ethiopia; but they have not been evaluated scientifically; hence, old SWC measures have been evaluated in this study. Investments in SWC practices enhance crop production, food security and household income Adgo et al. Studies show that despite the availability of many best SWC practices in watershed management, they are highly localized, and are not being expanded to other areas, while land degradation due to soil erosion and deforestation are still the main problems in Ethiopia.
Other studies such as Tesfaye et al. This is because investments by farmers in SWC are influenced by ecological, economic and social impacts of the SWC technologies.
Despite the massive mobilization of resources for SWC measures, only a few studies have been done to evaluate the effectiveness of integrated watershed management on rehabilitation of degraded watershe. Likewise, the lowest sediment deposition There was overflow of sediments along the old SWC structures. Farmers in the lower part of the watershed used cut-off drains to reduce the over run-off and sediments on their cultivated land; and the upper beneficiaries increased the height of the structures on their farmland when they filled with sediments.
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. Code defines standard methods recommended by the U. Natural Resources Conservation Service.
If you do not have Acrobat Reader, click here to download it. This tool calculates the value of broiler litter based on prevailing retail selling prices of common fertilizer materials containing nitrogen N , phosphorus P and potassium K. ZIP, 6.
Principles of Soil Conservation and Management pp Cite as. Soil is the most fundamental and basic resource. Soil is a vital resource that provides food, feed, fuel, and fiber. It underpins food security and environmental quality, both essential to human existence. Essentiality of soil to human well-being is often not realized until the production of food drops or is jeopardized when the soil is severely eroded or degraded to the level that it loses its inherent resilience Fig.
Cation exchange capacity CEC 2. The population of the world is dependent on land resource for food and other necessities. Soil and water resources conservation and management is important for the welfare of the people Lal,
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PDF | Conservation of soil and water resources is important for sustainability of agriculture and environment. Soil and water resources are.