Upholding ecosystem services of soil for climate security
Adaptation to climate is the process through which people reduce the adverse effects of climate on their health and well-being, and take advantage of the opportunities that their climatic environment provides
SHISHIR REZA
Soil or land is the mother of all resources and acts as a mitigating factor of climate change. It is an essential natural building block in our environment for biological communities. Soil provides water, nutrients for plants and trees in natural forests and Grasslands, perennial crops and planted grassland. It has an essential role in the cycling of carbon and mineral nutrients. Soil has ion exchange properties, acts as a buffer for temperature change and for the flow of water between the atmosphere and ground water.
An ecosystem can be defined as a community of interacting organisms and its environment functioning as a reasonably self-sufficient unit. 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 of nutrients on which plant growth depends. 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. In this context, soil creates an ecosystem which interacts with each other and with their physical and chemical environment.
The ecosystem services of soil include Production of biomass, Storage, filtration and transformation of nutrients, Provision of habitat, species and genetic biodiversity, Provision of raw materials, Carbon storage and cycling. Soil condition determines its ability to provide ecosystem services: 1. Water purification and soil contaminant reduction which functional processes are atmospheric deposits, applied fertilizers, pesticides, clay particles, organic matter degraded by soil biota and contributing factors are soil texture, soil structure, organic matter, genetic biodiversity of soil biota; 2. Source of biochemicals and pharmaceuticals which functional processes are bio-diverse soil biota could be a source of new pharmaceuticals, recycle dead vegetative matter and organic waste products releasing nutrients available for plants and contributing factors such as soil structure, organic matter, availability of water and oxygen, PH ,toxic ions; 3.Carbon sequestration which functional processes are carbon, soil organic matter, 58% organic carbon and contributing factors are carbon storage capacity, nutrient availability, temperature, soil moisture, biotic activity of soil, vegetation; 4. Nutrient cycling including food fiber production which functional processes are soil biota, mineral, organic matter and contributing factors are fungi, different roots, chemical fertilizers, nutrient availability; 5. Regulation of green house gases which functional processes are CO2, CH4 and N2O and contributing factors are soil moisture, nutrient content, microbial activity; 6. Remediation of Soil contaminated by diffuse airborne pollution which functional process is Soil biota metabolize contaminants through oxidative or reductive processes and contributing factors are Microorganisms require nutrients (C, N, P), moisture (generally at 40-60%), appropriate pH (5.5-8.5) and appropriate temperature (15-450C) plus oxygen for the oxidative processes.
Besides healthy soil regulates flooding, screens the pathogen, keeps the limit contaminants and agrochemicals and storages of carbon and other greenhouse gases. The soil carbon sequestration is a bio membrane that filters pollutants, reduces sediment load in rivers, decreases hypoxia in coastal ecosystems, degrades contaminants and is a major sink for atmospheric CO2 and CH4. It is a strategy to achieve food security through improvement in soil quality. While reducing the atmospheric concentration of CO2, soil Carbon sequestration improves and sustains agronomic productivity. It has the potential to offset fossil-fuel emissions by 5 to 15% of the global emissions. Irrespective of the climate debate, the Soil Oxygen Carbon stock must be restored, enhanced and improved.
Nowadays unstable level of natural temperature, humidity and rainfall has created an apprehension of climate change. Ecosystem services of Soil plays an important role in climate change mitigation by storing carbon and decreasing greenhouse gas emissions in the atmosphere. Restoration of degraded soils and adopting soil conservation practices, there is major potential to decrease the emission of greenhouse gases from agriculture, enhance carbon sequestration and build resilience to climate change. The carbon cycle is the exchange of carbon between the atmosphere, ocean, terrestrial biosphere and geological deposits.
Carbon sequestration occurs when carbon from the atmosphere is absorbed and stored in the soil. This is an important function as more carbon that stores in the soil, the less carbon dioxide there will be in atmosphere contributing to climate change. Such as, Plants use carbon dioxide from the atmosphere, water from the soil and sunlight to make their own food and grow in a process called photosynthesis. The carbon they absorb from the air becomes part of the plant. Most of the carbon the animals consume is converted into carbon dioxide as they breathe and released back into the atmosphere. When the animals and plants die, the dead organisms are eaten by decomposers in the soil and the carbon in their bodies is again returned to the atmosphere as carbon dioxide. In some cases, the dead plants and animals are buried and turn into fossil fuels, such as coal and oil.
Climate change represents a serious threat to global food security, not least because of its effects on soils. Changes in temperature, humidity and rainfall patterns can have a great impact on the organic matter and processes that take place in our soils, as well as the plants and crops that grow from them. In order to meet the related challenges of global food security and climate change, agriculture and land management practices must undergo fundamental transformations. Soil management practice increases soil organic carbon, such as agro-ecology, organic farming, agricultural conservation and agro forestry.
The Organic Soils and Peat lands are capable to promote strategic action for reducing greenhouse gas emissions. It is useful to consider a biochar-based strategy against more established approaches to increase the organic carbon stored in soil, such as the use of manures and composts.
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. Although conversion of soil has been promoted as an approach to enhance soil organic matter as well as to control erosion and conserve water.
Adaptation to climate is the process through which people reduce the adverse effects of climate on their health and well-being, and take advantage of the opportunities that their climatic environment provides. There are several sources of nutrients for Carbon sequestration, including biological nitrogen fixation, recycling from subsoil, aerial deposition, use of bio solids, and crop residues. One ton of cereal residue contains 12 to 20 kg N, 1 to 4 kg P, 7 to 30 kg K, 4 to 8 kg Ca, and 2 to 4 kg Mg. It can be used either for bio fuel production or to sequester Carbon and improve soil quality. Although a part of the Carbon translocated by erosion may be redistributed, the rest is emitted into the atmosphere either as CO2 by mineralization. Enhancing Soil Organic Carbon stock increases the soils capacity to oxidize CH4, especially under no-till farming but may also exacerbate emission of N2O. Fluxes of CH4 and N2O may change the CO2-mitigation potential of soil management practices and must be considered along with Carbon sequestration.
The inimical pollutants from physical, biological, air-borne, biocides, chemical fertilizers, urban, industrial sources and human activities such as mining, deforestation, land use changes, heavy canal irrigation, discharging of waste water, all are disrupting the soil health. In order to adapt with climate change, we have to conserve soil through diverse Methods; Biological: includes cover of vegetation during the periods of high erosion risk, good crop management, use of rotations, cover crops to stabilize slopes, Strip planting, mulching with stubble and weeds; Cultivation: includes use of ordinary farm implements to prepare land for an arable crop, 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.
The writer is an
environment analyst
