There is around 15 billion hectares of land worldwide. Agriculture uses more than 4.5 billion hectares, or 30 per cent, of the world’s land area, and cropland currently covers around 1.5 billion hectares (10 per cent) of the global land area. Over the last 5 decades, the area used for agriculture has been expanding, primarily at the expense of forests.
Under business as usual conditions, the growing demand for food and non-food biomass could lead, by 2050, to a gross expansion of cropland worldwide in the range of 320 to 850 million hectares more . Expansion of such magnitude would necessarily mean encroaching further into forests, grazing lands and natural areas, at the expense of the basic life-supporting services that ecosystems provide, such as maintaining soil productivity, regulating water resources, sustaining biogeochemical cycles or conserving biodiversity.
India’s land area is about 330 million ha, of which almost 50% is cultivable land, and of that, about 50% has been partially degraded through faulty cropping practices. Around 2 per cent of this India is covered by cities and infrastructures (built-up land), and this area is growing. Built-up land is expected to cover 4 to 5 per cent of the global land area in 2050, most of it by expanding into agricultural land.
Since the massive fluctuations in food prices a decade ago, investors have gone on a spree to purchase large amounts of land overseas. Over this short period, these investors, from China, India and several other countries have bought land in Africa, Latin America and other regions that is considerably greater than the entire land area of Portugal or the state of Bihar. The magnitude of these purchases presumably reflects the expectation of these investors that domestically available land will be insufficient to meet the future demand of food.
At par with water, soil is probably the most critical natural resource for supporting life in general and humans in particular. Top soil is an enormously complex, active, living substance which takes nature millennia to create. A cubic centimetre of it contains literally millions of living organisms in it. It is not only the base of virtually all crop production, but also has other, competing uses in the economy, such as making bricks and other construction materials, and for being paved over by human settlements, roads and other infrastructure.
Physical, biological and chemical processes can degrade land and, particularly, its soil, for example by reducing its organic matter content, biomass carbon, diversity of soil fauna and flora and its nutrients.The implications of land degradation have upon agriculture productivity and it is a serious problem in India too. According to Indian Parliament proceedings, the nation is losing about one millimeter of topsoil each year with a total loss of 5,334 million tons annually due to soil erosion .
Approximately 140 million hectares land area of the country is affected by water and soil erosion as a result of which the top fertile layer of the soil is lost annually at the rate of 6,000 million tons per year containing more than Rs.1, 000 crores worth of nutrients. The amount of micronutrients like nitrogen, phosphorus, and potassium lost during this process is about 5.53 million tons.
Land and soil degradation is a serious problem in India, which needs to be tackled because shrinking of land resource base will lead to a substantial decline in food grain production which in turn would hamper the economic growth rate. In India, about 50 million hectares of land area is affected by wind erosion most of which belongs to Rajasthan and Gujarat; sometimes over-grazing is considered to be the main cause.