How soil erosion and land degradation affect agriculture and human settlements

Introduction

Land is the base of both farming and settlement. When its top layer is lost or its quality falls, the damage reaches the farmer's field first and then the village and the town. Land carefully used behaves like a renewable resource, but misuse can turn it into wasteland.

Soil erosion and land degradation: what they are

• Soil erosion is the removal of the surface litter and the topsoil from one place to another. Wind and running water cause it naturally, but farming, construction, overgrazing, burning of grass cover and deforestation speed it up greatly.
• Land degradation is the wider loss of the land's productive capacity. Over-intensive farming, over-irrigation (which brings salts to the surface and waterlogs the topsoil) and heavy use of chemical fertilisers all degrade farmland; worldwide, about 5 to 7 million hectares are added to degraded farmland every year.

Once fertile land has been stripped or poisoned in this way it can end up as wasteland, which is among the pressing problems of the country.

Effects on agriculture

1. Lower fertility and yields. The topsoil carries most of the humus and soil organisms; once it is washed away the soil is less fertile and holds less water.
2. Saline and waterlogged fields. Over-irrigated land turns salty or waterlogged, crop roots suffer and the crop deteriorates; such land may finally grow nothing.
3. Shrinking cultivable land. Loss of soil has already ruined a large amount of cultivable land in India, and if unchecked it will affect the land that remains.

Effects on human settlements

1. Floods. Where Himalayan catchments are deforested, run-off carries topsoil down, rivers swell, burst their banks and flood farms and homes in the plains year after year, killing people, damaging crops and destroying homes along the Ganga and the Brahmaputra.
2. Drinking water problems. Silt washed into streams and lakes clogs them and makes the water turbid; aquatic life is lost too, so the water that nearby settlements depend on is degraded.
3. Loss of land to towns and industry. As cities and industries spread, farmland and forests shrink, which has long-term ill effects on society.
4. Pressure on the remaining land. Unless good land is safeguarded, settlements may face shortages not only of food grains but of vegetables, fruit, fodder and fuelwood.

As an illustration, a hill village in Uttarakhand that clears its slopes for fields may first see brown, silt-laden streams, then poorer harvests, and finally floods reaching its houses in a heavy monsoon.

Conclusion

Soil erosion and land degradation work slowly but cut at the roots of farming and settled life. Protecting forest and grass cover, avoiding over-irrigation and excess chemicals, and reclaiming wasteland are therefore basic to food security and safe settlements.