ABSTRACT
World soil resources are finite, unequally distributed among diverse regions, fragile and prone to degradation by land misuse and soil mismanagement, and vulnerable to extreme events related to the abrupt climate change (ACC). The land area prone to degradation processes is estimated at 3500 Mha affecting livelihood and wellbeing of a large proportion of underprivileged population living in regions characterized by a harsh climate and agriculturally marginal lands (Bai et al. 2008). Further, the resource-poor farmers are unable to invest in soil and water conservation techniques and in replenishing soil fertility. Thus, a perpetual use of extractive farming practices by small landholders of the tropics and subtropics and cutting corners for quick economic returns by large-scale commercial farmers have exacerbated the problem of a widespread distribution of depleted and degraded soils, often with a truncated topsoil layer because of the accelerated soil erosion (Lal 2001, 2003). Whereas the area equipped for supplementary irrigation has expanded to ~287 Mha (FAO 2012), it has also caused severe problems of groundwater depletion (Lal and Stewart 2012) and secondary salinization (Oldeman 1994). Yet, the food production must be drastically increased to feed a world population of 10 billion (Borlaug and Dowswell 2005), to meet the food demands of the growing population and changing the dietary preferences toward more animal-based than plant-based diet. By 2030, global cereal demand for food and animal feed is expected to be 2.8 billion Mg/year, which is double the production in 2005 (Lobell et al. 2009). With a small, if any, scope for bringing new land under cultivation, productivity must be increased from the existing agricultural land per unit area, time, and use of energy-based input (i.e., fertilizer, irrigation). In accord with the concept of zero net land degradation (Lal et al. 2012), any new land degradation must be negated by restoration of prior degraded land.
