Healthy soil has a good combination of soil structure, chemistry, organic matter content, biology, and water permeation for its type. Increasing concentrations of heavy metals, depending on their presence in the soil due to the application of fertilizers and other sources in the watershed, landscape and soil degradation implies a reduction in ecosystem functions and services. Therefore, decisions on sustainable landscape management must take into account the restoration of essential ecosystem services (Forouzangohar et al., 2014). It is important to identify hotspots of important ecosystem services in a landscape and prioritize these areas. These services, with many co-benefits, include soil and ecosystem carbon sequestration (Lal et al., 2013), renewable water supply, and biodiversity. There is a close interaction between ecosystem services and biodiversity that are mutually beneficial or even symbiotic (Schneiders et al., 2012). The conversion of natural land to agroecosystems reduces biodiversity with adverse effects on it. Therefore, restoring biodiversity in agricultural landscapes is important to improve ecosystem services while maintaining agronomic productivity. Land sharing, rather than land separation, can improve agricultural environments and includes biodiversity-based agricultural practices (Benayas and Bullock, 2012). Afforestation of agroecosystems to improve biodiversity has the side effect of generating another source of income for carbon credits (Perring et al., 2012; Schneiders et al., 2012). Therefore, the economic analysis of landscape restoration must take into account all side effects and trade-offs.
“When the soil deteriorates, the processes that take place there are damaged. This leads to a decline in soil health, biodiversity and productivity, leading to problems at all levels of many ecosystems and major environmental impacts such as flooding and mass migration. Silvia says: “Several practices associated with intensive agriculture, especially tillage, disrupt the structure of the soil. They accelerate surface runoff and soil erosion, loss of organic matter and fertility, and disruption of water, organic carbon and plant nutrient cycles. These practices also have a significant negative impact on soil biodiversity. It is important to note that the measurement of each indicator should express the direction (positive, negative, increase or decrease, etc.) and size (as a percentage of a reference value) of the change, as well as the intensity, duration and extent of the change (Ribeiro et al., 2009) so that it can measure the stage of soil degradation. Soil depletion occurs when nutrients and other components that contribute to soil vitality and fertility are removed, not replaced. You may think that a handful of earth is little more than dirt, but it is often much more. In fact, a teaspoon of healthy soil can be made up of more organisms than people who live on the planet. According to Silvia Pressel, a researcher in the Department of Algae, Fungi and Plants at the National History Museum in London, soils can contain “millions of things that humans cannot see, like microorganisms and all the fascinating work they do together.” CAS are complex and simulate non-linear relationships between their components, characterized by positive and negative feedback mechanisms.
They are adaptive because system actors organize themselves according to external and internal inputs, which are both determinants and products of the system function (Salvati and Zitti, 2008). These properties are thought to allow CAS to better simulate the dynamics of complex systems such as soil. Most of the world`s soils have depletion of one or more elements essential for plant growth – including zinc, boron, iron, molybdenum and manganese – thus reducing crop yields. Low levels of iodine, cobalt and copper in the soil also affect the health of grazing livestock and are therefore indirectly harmful to the human food supply. A low degree of soil fertility can result from natural geological and geochemical processes, but anthropogenic interventions can often cause or accelerate the problem. For example, the process of salinization of land most often develops from poor irrigation practices, especially when excess water is added to the soil, which allows for high evaporation rates and the development of hard mineral reservoirs (irrigation salinity). Such salinization affected the civilizations of Mesopotamia as early as 2500 BC. J.-C. In which plants began to fail more and more due to the gradual accumulation of salt. This problem caused a conversion of wheat to barley, which is more tolerant of salt, until many countries (and the city-states they supported) were completely abandoned.
Another form of salinity, salinity in the mainland (“salt creep”), results from the change in vegetation cover. After cleaning up the original plants and replacing them with shallow root plants, evapotranspiration in cultivated areas decreased, leading to an increase in groundwater levels and triggering the release of soluble salts. Productivity changes: Observation of changes in crop yields, biomass production and livestock production that apply directly to the definition of land degradation in terms of reduced productivity, although they are influenced by many other factors. There are a number of possibilities: at national level, national yield statistics (the reliability of which is still under discussion) adapted to the use of fertilisers and the climate could be used. At the local level, yield monitoring is possible by comparing them to a standard crop, either without fertilizer or with standard fertilizer and management. This poses significant challenges, as the decline in productivity could be due to factors other than land degradation, such as the abolition of fertilizer subsidies or civil conflicts. The same cost restrictions apply as for soil monitoring. The millions of organisms that live in the soil interact with each other and contribute to a series of cycles that allow all life on Earth. These include the carbon, nitrogen and phosphorus cycles. There is also a strong link between desertification and the emission of C from soil and vegetation in dryland ecosystems.
Desertification is defined as the reduction or destruction of the biological potential of land, which can ultimately lead to desert conditions. Estimates of the magnitude of desertification are far-reaching and often unreliable. The area of land affected by desertification is estimated at between 3.5 and 4.0 billion hectares. The available data on the rate of desertification are also highly speculative, estimated by some at 5.8 Mha/year.