The importance of the topsoil cannot be undermined and left to erode, especially when it cannot be replaced or regenerated in a hurry
In the past few decades, soil erosion emerged as a serious challenge for both environment and natural biodiversity. Worldwide, soil erosion has come to be regarded as a major environmental and agricultural problem that has the capacity to score a hard hit on agricultural productivity, thereby having a direct debilitating impact on food security. Soil erosion also adversely impacts environmental sustainability and undermines the ability of the environment to be resilient against climate change. It is also a major economic threat to the growth and prosperity of agricultural farmers which is manifested in the form of crop failures. This in turn fuels excessive migration of the population from rural areas to urban areas.
Soil erosion by itself is a simple phenomenon whereby soil and rock are removed due to wind/water, and then transported and deposited in other locations. As mentioned above, there are two types of soil erosion — water and wind. Soil erosion from water comes in the form of rain and runoff. As rain falls, it breaks up soil particles, especially fine sand and silt, and disperses them. This destruction of soil increases with thunderstorms or heavy rain. Wind erosion, on the other hand, creates adverse operating conditions and leads to topsoil destruction, especially in the agricultural field.
According to scientific studies, the impact of wind erosion on agriculture is quite challenging. Wind erosion is known to cause total destruction of crops, leading to mounting debts for farmers as investment is doubled on the same crop. This is due to the fact that once the adverse effect of wind erosion takes its full form, farmers have to incur costly delays as they have to undertake crop reseeding process and engage in applying necessary manures and irrigation facilities, all of which are repeat costs. This reduces profit margin and renders the crop a total loss.
A repeated cycle of wind erosion may also result in a decrease in yield, loss of quality and market value of the crop due to continuous sandblasting. The main cause of soil erosion is the removal of vegetation. The process of vegetation removal takes place due to removal of forest covers. Unscientific farming has also led to barren lands. The removal of vegetation exposes the topsoil to water and wind. Constant exposure to the vagaries of water and wind extremities leads to the removal of topsoil, resulting in crop damage.
India is no stranger to soil erosion. According a report prepared by National Centre for Coastal Research (NCCR), an institute under the Ministry of Earth Sciences, a staggering one-third of almost the entire Indian coastline was lost due to soil erosion in the last 26 years. India has a total coastline of 7,517 kilometres. Of this, 6,031 kilometres were surveyed and 33 per cent of it was found eroded. West Bengal recorded the highest erosion, losing 99 sq km of land in the past 26 years. The erosion was more on the eastern coast beside the choppy Bay of Bengal rather than on the western coast beside the calmer Arabian Sea.
The NCCR report states that 2,156.43 kilometres of the country’s surveyed coastline faced erosion. The survey used data from five satellites — Landsat 5 and 7 (operated by NASA), ISRO’s Resources at 1 and 2 and Cartosat-1. This underlines the authenticity of the report. Given the fact-based study, it is critical for the Government to take immediate steps to protect the precious topsoil from erosion. Topsoil is of critical importance to all countries in the world. Topsoil is the upper, outermost layer of soil, usually the top two inches (5.1 cm) to eight inches (20 cm). It has the highest concentration of organic matter and microorganisms, and it is where most of the Earth’s biological soil activity occurs. Plants generally concentrate their roots in and obtain most of their vital nutrients from this layer.
As such, the importance of topsoil cannot be undermined and left to erosion, especially when the same cannot be replaced or regenerated in a hurry. According to studies, it takes approximately 500 years to replace 25 millimeters (one inch) of topsoil lost to erosion. The minimal soil depth for agricultural production is 150 millimeters. From this perspective, productive fertile soil is non-renewable and endangered ecosystem. In order to stem the damage from soil erosion, local authorities, in coordination with the Union Government and State Government, must embark on a mission to prevent activities that encourage soil erosion. Human activities, such as excessive construction and dredging of ports, are seen as the precipitating factors for a rise in erosion related matters.
In order to prevent erosion from assuming serious proportions, land use needs to be in accordance with its capability. It is also vital to protect the soil surface with some form of cover, and thereby control runoff before it develops into an erosive force. These activities can be complemented by growing more trees and grasslands. Soil erosion also leads to desertification and today there are more than 25 million hectares of barren lands in the world. It can get much worse unless soil erosion is dealt with on a priority basis.
(The writer is an environmental journalist)