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Erosion by Water: Amendment Techniques
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Soils and Terrestrial Systems, 2020
Animal, farmyard, and green manures have been used as organic soil amendments to improve soil productivity for many centuries. Since the 1990s, application of municipal biosolids (sewage sludge) and industrial waste compost such as paper sludge to agricultural lands has increased dramatically. These materials have the ability to increase soil aggregate stability, porosity, and water holding capacity; reduce water runoff and soil erosion; improve soil tilth; increase plant nutrient availability and soil cation exchange capacity; and elevate soil microbial activities.[3] Decomposed organic substances such as humus along with soil clays are primary binding agents for soil aggregation. An increase in soil organic matter content often leads to increases in soil aggregation and structural stability. Thus, addition of organic materials such as manure and compost reduces soil erosion by water by improving soil aggregation, reducing runoff, and increasing soil resistance to erosion. In addition, improved soil conditions and fertility enhance root and plant growth, resulting in greater plant cover and root biomass, which further protect soil and reduce soil erosion. Large amounts of these organic amendments must be applied over decades to substantially increase soil humus levels.
Management, Operations, and Maintenance
Published in Robert H. Kadlec, Treatment Marshes for Runoff and Polishing, 2019
Plant growth is monitored by estimating percent cover, species composition and possible physical attributes such as plant height. These nondestructive techniques are used to ascertain the status of plant development before and during wetland treatment system operation. Plant cover is an estimate of the percentage of the total ground area covered by stems and leaves. This parameter can be estimated by walking through or next to a plant stand and visually determining a cover category for the plants, or by aerial photography. Cover estimates can be made on a finer scale by using a frame to delineate specific areas. Cover estimates should be made at enough locations in the constructed wetland to provide reasonable statistical averages for comparison between cells and between dates.
Environmental Impacts of Drought on Desertification Classification
Published in Saeid Eslamian, Faezeh Eslamian, Handbook of Drought and Water Scarcity, 2017
Dalezios Nicolas R., Eslamian Saeid
Many studies have demonstrated that in a wide range of environments, both runoff and sediment loss decrease exponentially with an increasing percentage of vegetation cover [8]. Forest vegetation reduces significantly the summer soil surface temperatures and it is necessary for the regeneration of many forest species in the Mediterranean. A vegetation cover of the order of 45%–50% is considered as a critical value, since above this value soils are adequately protected from raindrop impact and soil erosion is significantly reduced [11]. Moreover, both runoff and sediment loss are greatly affected by plant cover reducing raindrop impact. Furthermore, as already mentioned, plant cover significantly prevents the increase of the summer soil surface temperatures and soil water conservation. Plant cover is a crucial indicator of land desertification, especially in areas affected by water stress. In addition, climate greatly affects plant cover. Indeed, high annual air temperatures promote low plant cover due to high evapotranspiration demands. Furthermore, low amounts of annual rainfall negatively affect plant cover. In addition, high rain seasonality indices usually promote low plant cover percentages. Furthermore, soil depth, soil texture, and exposure of rock outcrops greatly affect soil water storage capacity and, therefore, plant growth and plant cover under semiarid or arid climatic conditions.
Clipping strategy to assist phytoremediation by hyperaccumulator Dicranopteris dichotoma at rare earth mines
Published in International Journal of Phytoremediation, 2020
Mine wastes are often prone to water and wind erosion, resulting in the spread of toxic wastes into nearby agricultural fields and water bodies (Romeo et al.2014). The establishment of a dense plant cover is crucial for limiting water and wind erosion and can further reduce leaching, increase biodiversity, and help develop a healthy and functional soil ecosystem (Gómez-Sagasti et al.2012). Thus, phytoremediation should avoid the need for soil excavation and transport that are disruptive to ecosystems. Some scholars have suggested that one management factor that can greatly influence soil erosion is whether plant residues are left on the field and incorporated into the soil, and if plant residues are completely removed, soils can become vulnerable to erosion (Evangelou et al.2015). A partial removal of 25% of stover is considered the maximum rate that might be enough to control wind erosion in no-tillage soils (Blanco-Canqui and Lal 2009). Thus, the underground biomass of D. dichotoma should be retained for phytoremediation at rare earth mines.
Effect of biochar, iron sulfate and poultry manure application on the phytotoxicity of a former tin mine
Published in International Journal of Phytoremediation, 2021
Manhattan Lebrun, Florie Miard, Romain Nandillon, Domenico Morabito, Sylvain Bourgerie
Phytomanagement is the manipulation of the soil-plant system to control metal(loid) fluxes in the environment (Robinson et al.2009). It relies on the establishment of a plant cover, often with the help of amendment application, to mitigate the environment risk posed by the contaminated area (Robinson et al.2009). The application of amendments improves soil conditions and reduces its toxicity, allowing the development and growth of plants on the site, and therefore the stabilization and/or take up of metal(loid)s. Ideally, such plant cover will also deliver additional benefits to the land, such as soil erosion prevention, surface and groundwater flux management, carbon sequestration, and greenhouse gas emission reduction (Burges et al.2018).