Understanding Land Degradation

Much of the Earth’s population has become dependent on agriculture as it provides food for the sustenance of animals including man. Land and climate determine to a great extent successful crop production. Soil which is developed from rocks over thousands of years is the main component of land. Land degradation which refers to the loss of the intrinsic physical, chemical, and biological qualities of soil, causes soil fertility to decline and is one of the pressing environmental problems the world is facing today. Globally, about 25% of the total land area has been degraded. If this trend continues, 95% of the Earth’s land areas could become degraded by 2050. Land degradation is caused by many factors. Among these are heavy rainfall causing soil erosion, hilly topography, deforestation and strong winds. Soil degradation is a problem mainly in tropical developing countries, where poor management practices are common. The effects of soil degradation can often be mitigated, prevented and even reversed through the use of sustainable farming techniques and better land management practices. Policy makers need to realize the dangers of land degradation, and take relevant action to reduce and reversing land degradation.

Land degradation, a decline in land quality caused by many factors, was a major global issue during the twentieth century and will continue to be so in the twenty-first century. Globally, around 3.2 billion people especially in rural communities are affected by land degradation. A number of factors cause land degradation. Among these are natural hazards such as heavy rainfall which cause soil erosion. Land degradation due to wind erosion is common in semi-arid and dry climates. Sandy soils and uncovered lands are prone to wind erosion. Land degradation tends to be common in areas where the topography is hilly and where there is no adequate cover. Unsuitable land use also causes land degradation. Soils in waterlogged alluvial plains or interior basins with restricted outward drainage of groundwater tend to be saline and such lands are less productive and degraded unless crops such as rice which can stand water logged conditions are cultivated. In many countries, steep slopes and mountain lands are cultivated by landless poor people who have limited resources to implement practices to control land degradation. Population growth; a lack of alternative avenues of livelihood, and inequity all contribute to land degradation.

Millions of people around the world are affected by land degradation, a trend that may worsen by 2050. According to Food and Agriculture Organization, 33% of the Earth's soils are already degraded and over 90% could become degraded by 2050. The productivity of some lands has declined by 50% due to land degradation. In South Asia, the annual loss in productivity due to soil erosion is estimated at 36 million tons of cereal valued at US$5,400 million. It is estimated that the total annual cost from agriculture due to soil erosion in the USA is about US$44 billion per year, i.e. about US$247 per ha of cropland and pasture. On a global scale, the annual loss of 75 billion tons of soil costs the world about US$400 billion per year, or approximately US$70 per person per year. In addition to the decrease in land productivity, floods and droughts, increase in poverty and lowered food security are effects of land degradation. Increase in poverty tends to affect the health, education and standard of living of millions of people mainly in Asia and Africa.

Land degradation is one of the world’s most pressing environmental problems and it will worsen without rapid remedial action. Globally, about 25% of the total land area has been degraded and 24 billion tons of fertile soil was being lost per year, largely due to unsustainable agriculture practices. If this trend continues, 95% of the Earth’s land areas could become degraded by 2050. Globally, 3.2 billion people are affected by land degradation, especially rural communities, smallholder farmers, and the very poor. The problems are particularly severe in the driest parts of the planet. Dryland landscapes cover approximately 40% of the world’s land area and support two billion people. The vast majority of people who depend on drylands live in developing countries, where women and children are most vulnerable to the impacts of land degradation and drought. Land degradation causes a decrease in its productivity. According to Food and Agriculture Organization, 33% of the Earth’s soils are already degraded. Hence, it is extremely important that action is taken by farmers as well as relevant authorities to control this process. The main issue related to land degradation is soil erosion caused by water and wind. Hence, It is important that appropriate action is taken to control soil erosion. One of the important methods to control erosion is reducing the amount and velocity of run-off water by constructing contour drains to remove the run-off water. Terracing is an extremely effective means of erosion control in hilly areas, which has been practiced for thousands of years by people all over the world. Having a soil cover or a mulch to protect the top soil from the impact of raindrops is also a strategy to control land degradation. Wind breaks are rows of trees planted along the edges of agricultural fields. These control erosion by wind. Traditional planting methods, such as mixed-cropping and crop rotation have also been shown to significantly reduce soil erosion and hence land degradation. Zero tillage, sloping agricultural land technology (SALT) and cultivation of vetiver on sloppy lands are also effective methods to control land degradation in sloping lands. Communities affected by erosion need to take measures to control this process.

Land degradation is characterized by the loss of natural resources including soil, vegetation and water causing a reduction in agricultural productivity. It is a major threat to food security and the resilience of rural communities while contributing to climate change and biodiversity loss. Land degradation has brought food security to ‘critical’ levels in many parts of the world. Hence, reducing land degradation and restoring degraded land is an urgent priority to sustain food production, alleviate poverty and protect biodiversity and ecosystem which are vital to all life on Earth. Although land degradation is a global problem, it takes place locally. Hence greater commitment and more effective cooperation at the local level are necessary to control land degradation and loss of biodiversity. Controlling land degradation prevents the reduction of crop yields, increases food security and employment opportunities and reduces poverty leading to better living standards among the poor and benefits the environment and the communities. It reduces eutrophication and enables achieving some of the Sustainable Development Goals. It also provides improvements to marginal areas so that they could be effectively used.

Nearly 80% of the energy the world needs is obtained from fossil fuels such as oil, coal, and natural gas. The gasses such as carbon dioxide (CO₂) and methane (CH₄) emitted during the process of burning fuels tend to contribute to climate change which is one of the two major global catastrophic changes predicted for the future, the other being land degradation. Climate change can be attributed to several processes which cause land degradation. One of these processes is increased rain fall in some areas of the world, which cause soil erosion leading to land degradation. Another process is drying of the environment due to low rain fall causing drought also resulting in land degradation. Climate change may continue to occur in the coming decades and result in further land degradation causing a catastrophe in the world.