Soil degradation in India is estimated to be occurring on 147 million hectares (Mha) of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors. This is extremely serious because India supports 18% of the world’s human population and 15% of the world’s livestock population, but has only 2.4% of the world’s land area. Despite its low proportional land area, India ranks second worldwide in farm output. Agriculture, forestry, and fisheries account for 17% of the gross domestic product and employs about 50% of the total workforce of the country. Causes of soil degradation are both natural and human-induced. Natural causes include earthquakes, tsunamis, droughts, avalanches, landslides, volcanic eruptions, floods, tornadoes, and wildfires. Human-induced soil degradation results from land clearing and deforestation, inappropriate agricultural practices, improper management of industrial effluents and wastes, over-grazing, careless management of forests, surface mining, urban sprawl, and commercial/industrial development. Inappropriate agricultural practices include excessive tillage and use of heavy machinery, excessive and unbalanced use of inorganic fertilizers, poor irrigation and water management techniques, pesticide overuse, inadequate crop residue and/or organic carbon inputs, and poor crop cycle planning. Some underlying social causes of soil degradation in India are land shortage, decline in per capita land availability, economic pressure on land, land tenancy, poverty, and population increase. In this review of land degradation in India, we summarize (1) the main causes of soil degradation in different agro-climatic regions; (2) research results documenting both soil degradation and soil health improvement in various agricultural systems; and (3) potential solutions to improve soil health in different regions using a variety of conservation agricultural approaches.

Despite years of study and substantial investment in remediation and prevention, soil erosion continues to be a major environmental problem with regard to land use in India and elsewhere around the world. Furthermore, changing climate and/or weather patterns are exacerbating the problem. Our objective was to review past and current soil conservation programmes in India to better understand how production-, environmental-, social-, economic- and policy-related issues have affected soil and water conservation and the incentives needed to address the most critical problems. We found that to achieve success in soil and water conservation policies, institutions and operations must be co-ordinated using a holistic approach. Watershed programmes have been shown to be one of the most effective strategies for bringing socio-economic change to different parts of India. Within both dryland and rainfed areas, watershed management has quietly revolutionized agriculture by aligning various sectors through technological soil and water conservation interventions and land-use diversification. Significant results associated with various watershed-scale soil and water conservation programmes and interventions that were effective for reducing land degradation and improving productivity in different parts of the country are discussed.

Potassium availability to the plant is influenced by internal soil properties and other external properties. Quantity intensity characteristics are one of the satisfactory measures of potassium dynamics and its availability. So quantity intensity characteristics of potassium were studied to quantify the potassium availability in three different cropping systems viz., paddy-paddy, banana and paddy-pulse based. Three soil profiles were studied in each cropping system and soil samples were collected horizon wise for laboratory analysis. Q/I parameters were estimated by the method adopted by Beckett (1964a). Analysis of variance was performed to compare the impact of cropping system and pedons on different chemical and nutrient properties of soils. Significantly high organic carbon (0.47%), and available nitrogen (271.10 kg/ha), medium available phosphorus (17.00 kg/ha) and available potassium (230.50 kg/ha) recorded in paddy-pulse cropping system compared with other cropping system. Banana based cropping system recorded significantly higher clay (41.2%), soil reaction (8.24) and potassium fixing capacity (84.32%). The results of Quantity-Intensity (Q/I) dynamics studies shows that paddy-pulse based cropping system recorded high labile K KL (0.49 c mol (p+)/kg) and Potential buffering capacity PBCK (45.67 c mol (p+)/kg) whereas paddy-paddy cropping system recorded PBCK of 16.81 c mol (p+)/kg which needs frequent potassium fertilization. The results showed that most of the soil properties including K dynamics were greater extent influenced by changes in cropping systems which consecutively affects the potassium availability. Key words: Quantity intensity (Q/I) characteristics, cropping systems, soil properties, K dynamics.