Sustainable Land-use Systems for Rehabilitation of Highly Sodic Lands in the Indo-Gangetic Plains of North-western India: Synthesis of Long-term Field Experiments

Abstract

Land degradation is among the major challenges to meet the food requirement of ever-increasing global population. About 1 billion hectares of degraded lands are salt-affected, 54% being sodic soils. The traditional methods of applying chemical amendments for reclamation of sodic lands are costly enough and beyond the reach of small and marginal farmers and need government-support. Research efforts have shown that bioamelioration through increasing organic carbon through re-vegetation is a viable option to restore these sodic lands. To find out the suitable agroforestry systems and affordable technologies involving salt-tolerant trees, grasses, arable and under-explored crops including high-value crops which besides having quick soil reclamation capability can also produce forages for livestock, wood biomass for fuel-wood and timber, food products and medicine to sustain the livelihood security. A series of long-term field experiments were conducted during last three decades by the authors and other associate workers on highly sodic (pH >10) soils of semi-arid region using alkali water found at the site for irrigation. This paper aims to synthesize the results of long-term studies on the ecological restoration of highly degraded sodic lands by using agroforestry practices. A synthesis of successful agroforestry interventions and results obtained from these studies are highlighted in this paper. The results of these studies established the fact that by integrating salt-tolerant trees including fruit trees, forage grasses, arable crops and under-explored crops (including high-value aromatic and medicinal crops) and using appropriate technologies are practicable for increasing agricultural production on these degraded lands. Agroforestry systems can support reclamation of these soils without applying costly amendments and drainage materials and sustain the livelihood security of resource-poor farmers dependent on these marginal lands. The fertilizer salt-tolerant multi-purpose trees, nitrogen-fixing grass (Kallar grass) are suitable for reclamation, whereas high-value halophytes, and commercial crops are suitable for semi-arid region.