A Gold Medalist in Masters of Agricultural Statistics, Soil Laboratory Professional & Columnist
Soil is an integral part of the environmental components. It has huge significance for the wellbeing of human and other lives on the earth, Soil degradation is a severe problem in countries like India with high demographic pressure. For preventing and restoring soil degradation, the main issues will be controlling soil erosion and sedimentation with the associated risks of eutrophication of surface water and contamination of groundwater, combating desertification and enhancing soil carbon sequestration to improve soil quality/productivity and mitigate the greenhouse effect.
For sustaining better soil quality under intensive systems of agriculture, the emphasis should be on developing of workable soil quality indicators and methods to assess and monitor soil quality, assessment of soil quality under different land use management systems and to identify the effect of management practices aggrading/ degrading/ sustaining soil quality. Also, strategies need to be formulated to decide the amount of organic matter to be in the form of organic manures/organic waste/residue each year to maintain or build up the soil organic matter (SOM) level in various soil types.
Topsoil consists of organic carbon that helps in soil aggregation and also improves water holding capacity of the soil that in turn helps in slowing down the flow of water through the soil. An adequate amount of basic inorganic nutrients present in the soil is required for the healthy growth of vegetation. Thus, it is important to preserve topsoil from soil pollution, which is caused by construction materials and equipment during construction. Topsoil from a depth of about 6″-9″, from which the samples could be collected for testing of physical, chemical and biological properties.
Physical properties of the soil include water holding capacity, aeration, plasticity, texture, structure, density, and colour, etc. Chemical properties refer to the mineralogical composition and the content of the type of minerals such as Kaolinite, illite and montmorillonite, base saturation, humus, and organic matter content. The biological property refers to the content of extent and types of microbes in the soil which includes bacteria, fungi, worms, and insects.
Soil Testing is well recognized as a sound scientific tool to assess the inherent power of soil to supply plant nutrients. The benefits of soil testing have been established through scientific research, extensive field demonstrations, and on the basis of actual fertilizer use by the farmers on soil test based fertilizer use recommendations.
Soil pollution is one of the virtually invisible human impacts but affects everyone and everywhere. One-third of our global soil quality has degraded due to inappropriate management practices, population pressure driving unsustainable intensification and inadequate governance over this essential resource. Most of the pollutants originate from human activities, such as unsustainable farming practices, industrial activities and mining, untreated urban waste and other non-environmental friendly practices.
Soil testing should be made obligatory for all activities, where there is a disturbance to the soil environment. This could be excavation to waste and other material disposals on the earth. In order to make it effective, there is a need to establish appropriate soil quality standards, in terms of soil pollution limits.
Furthermore, the Ministry of Environment, Forest and Climate Change (MoEF&CC), the erstwhile Ministry of Environment and Forests (MoEF), delineates conditions in its environmental clearance letters to test the incremental pollution load in the soil environment. Such conditions are not uniformly mentioned in all project clearances, including those accorded by the MoEF&CC. A huge quantity of soil is excavated in major Construction projects, which obviously disturbs the soil microbes. Most of the environmental impact assessment (EIA) reports don’t address this part. Many times, EIA reports also contain generic statements like all the excavated earth shall be used in backfilling purposes, and the Construction and Demolition (C&D) Wastes shall be used for flooring and backfilling in roads, etc. to the maximum extent possible. Alike, water balancing, scientific material balancing of soil – e.g. excavated earth quantity versus the quantity of backfilling material required, C&D wastes versus the number of materials required for its reuse, could establish the veracity of claims. And, this could also support to bring desired results, which may be vital to control soil pollution and resource conservation.
It is an ongoing practice, which is also documented in various reports that dry sludge generated from the Sewage Treatment Plant (STP) is used as manure in green areas of a project. Some EIA reports have deliberated that the unused sludge shall be given to farmers or nursery. At a time, when the Government of India is concerned about Faecal Coliform in water, whether, such practices meet the norms? Should the government allow this practice without the characterization of sludge? According to a research article “Regrowth of faecal coliforms and salmonellae in stored biosolids and soil amended with biosolids” by R.A. Gibbs, C. J. Hu and others “results suggest that faecal coliforms and salmonellae were at undetectable concentrations through the summer period but were able to grow when provided with favourable conditions. From this limited trial, it was concluded that soil amended with biosolids could not be considered free from pathogens for at least one year following amendment.” Furthermore, the EC, recently accorded to the project, states that “Sludge from the onsite sewage treatment, including septic tanks, shall be collected, conveyed and disposed as per the Ministry of Urban Development, Central Public Health and Environmental Engineering Organization (CPHEEO) Manual on Sewerage and Sewage Treatment Systems, 2013.”
Although projects cleared by environmental impact assessment committees are not directly related to agriculture but have a greater significance in terms of soil pollution. Therefore, the government, as well as the Think-Tanks in the nation, may seriously consider this important area. In order to assess the impact of liquid effluent and solid as well as hazardous waste disposal, the State Pollution Control Boards and Committees should also delineate conditions in their consent to establish and consent to operate. Nevertheless, the Bureau of Indian Standards also reviews its standard test methods to make those simpler with the latest inputs. These acts could result in substantial preservation of the soil environment from unnatural contaminations.
The International Union of Soil Sciences (IUSS), in 2002, adopted a resolution proposing the 5th of December as World Soil Day to celebrate the importance of soil as a critical component of the natural system and as a vital contributor to human wellbeing. The day is also celebrated in India, though it is not so well known as World Environment Day or Earth Day or World Water Day. The Central and State Pollution Control Boards may infuse more knowledge on soil preservation amongst the projects and industrial establishments as well as the general public on the forthcoming World Soil Day.