Stop soil erosion and save our future
Healthy status of soil is fundamental for our natural environment. Structured and fertile soil works as a medium of ensuring food security as well as an adaptation and mitigation factor of climate change
Shishir Reza
On 5th December World Soil Day was celebrated all over the world. Every year on Soil Day the peoples of the world try to aware the other people about the importance of the soil and telling them about the causes, damages to soil erosion such as heavy damage by the Deforestation due to the cutting down of trees unnecessary. This time the theme of world soil day 2019 is the Stop Soil Erosion Save Our Future. Washing down of the upper layer of the soil by the inhabitants such as humans, animals, snow (glaciers), air, etc is called the process of soil erosion or it is also called one type of soil degradation. Nowadays unstable level of natural temperature, humidity and rainfall has created an apprehension of climate change. Both issues are closely interconnected with soil.
What is Soil Erosion?
General causes of soil erosion are, Surface runoff, continuously flow of streams and rivers; continuously deforestation by humans; flood cause heavy damage and with heavy flow; wind, uprooting of trees and plants cause deforestation; Mass movement, outward and downward movement of rock and sediments on a sloped surface due to force of gravity; deforestation is the main activity of human; farmers, by overusing of fertilizers in the crop fields; roads and urbanizations and low awareness towards the people about the importance of soil.
Healthy status of soil is fundamental for our natural environment. Structured and fertile soil works as a medium of ensuring food security as well as an adaptation and mitigation factor of climate change. Soil is a natural body comprised of minerals, organic matter, liquid and gases that occurs on the land surface, occupies space, and is characterized by one or both of the horizons or layers that are distinguishable from the initial material as a result of losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment. Soil provides water, nutrients for plants and trees in natural forests and grasslands, perennial crops and planted grassland.
It provides the habitat for decomposer organisms which have an essential role in the cycling of carbon and mineral nutrients. Soil acts as a buffer for temperature change and for the flow of water between the atmosphere and ground water. Soil has ion exchange properties and it acts as a pH buffer, retains nutrient and other elements against loss by leaching and volatilization. Heavy rainfall, the upper layer of the soil getting to displace
Soil, Human Life and Ecosystem
An ecosystem can be defined as a community of interacting organisms and its environment functioning as a reasonably self-sufficient unit. A terrestrial ecosystem consists of primary producers (trees, herbs, grasses) and decomposers (microorganisms, herbivores, carnivores). The primary producers are photoautotrophic, that is, they use some of the energy from the sun to convert atmospheric carbon dioxide into organic compounds, a process that requires water and nutrients which are supplied from the soil. The organic compounds are used by herbivores and carnivores as a source of energy, and carbon compounds are used to build their tissues; some of the energy is lost as heat and some of the carbon is respired as carbon dioxide. The most active group of decomposers is the soil microorganisms. The end product of oxidation of carbon in organic compounds is carbon dioxide, which returns to the atmosphere. The nutrients taken up from the soil are partly retained in the vegetation and the animals and partly returned to the soil. Although there are additions from outside, especially of water and there are usually leakages, for example in drainage water, the soil, vegetation and associated animals form a unit which is roughly self-contained. Soil is an essential component of the terrestrial ecosystem of Earth. It supports plant growth and provides a habitat for large numbers of animals and microorganisms that decomposes leaf, litter and plant residues, thereby helping to cycle the nutrients on which plant growth depends. Soil also supports the growth of arable crops, grassland and trees on which man depends for food, fiber, and wood for fuel and as a building material. An increasing world population requires more of these resources. This requirement can be met by bringing more land into cultivation, by more intensive use of land, or by a combination of the two. Soil creates an ecosystem which interacts with each other and with their physical and chemical environment.
The inputs are carbon compounds from the primary producers, water, oxygen and nitrogen from the atmosphere, and essential nutrients from mineral weathering. Between these extremes are life zones, in which soils support a particular type of flora and fauna and there is a characteristic climate. Tropical rainforest and boreal forests are examples of life zones.
Soil Profile and Climate Change
To understand the significance of carbon in soil in the form of biochar, it characteristics and dynamics should be compared to those of the remaining soil organic matter which accounts for most of the carbon that exists in soil. Peat soils comprise mainly organic matter and contain much more carbon on a per unit area basis. Most organic matter in soil is derived from plant roots, plant debris and microbial re-worked substances. The presence of soil organic matter is important for a range of useful soil properties. The process of microbial energy acquisition from substrate is accompanied by a release of various nutrient elements which may be conserved in the soil in microbial biomass.
A portion of certain nutrients may also be released in soluble form and a fraction may be lost from the soil through leaching or run-off; which is essential to crop nutrition. It is a case where external nutrient provision is limited. Overall, a balance slowly develops between the rate of carbon addition and the emission of CO2, which are specific to the land-use and environmental conditions. The amount of organic matter maintained once this balance is reached, depends on its average rate of turnover. Although conversion of soil has been promoted as an approach to enhance soil organic matter as well as to control erosion and conserve water. Managing decomposition in soil by manipulating the quality of inputs has been explored extensively in tropical environments where decay is rapid. Thus the main emphasis in the sequestration debate has been focused on increasing soil carbon by increasing organic matter additions in the form of straw or other crop residues, and from external sources such as manures and a range of organic wastes: sewage sludge, municipal compost, paper waste and so on.
Concluding Remarks
In order to adapt with climate change and meet the goal of food security we can conserve soil through different methods; biological: ways of maintaining a cover of vegetation during the periods of high erosion risk. It includes good crop management, use of rotations, cover crops to stabilize slopes, strip planting, mulching with stubble and weeds, correct stocking rate on pastures use of trees and hedges as windbreaks, cultivations: use of ordinary farm implements to prepare land for an arable crop. It includes contour ploughing, use of graded furrows and minimum tillage, mechanical: protection various forms of terrace, which are semi-permanent.
It includes graded channel, absorption terrace, bench terrace and irrigation terrace. Apart from that the soil erosion reduction strategies can be grow more trees and plants; terrace farming is the best method of farming; windbreaks, we should plant trees and shrubs along the agricultural fields; Our farmers should reduce the use of an excessive amount of fertilizers; farmers should use mixed farming method than the single crop in the agricultural fields; We should also use crop rotation which enhances the quality of soil; we should plant trees with highly deep roots; make a group of peoples and tell the importance of the soil to the people who are not aware of the causes of soil erosion and soil pollution; tell the farmers that dont use fertilizers for farming will help to reduce the soil pollution and erosion of soil; tell the peoples that dont use the plastics items for daily use because it is undecomposable harmful material which causes soil pollution and people suffer from soil diseases.
The writer is an Environmental Analyst and Associate Member, Bangladesh Economic Association.
