Rehabilitation of degraded sodic land through agroforestry and monoculture plantationswca2014-1874 Kripal Singh 1,*Bajrang Singh 2D D. Patra 1 1Soil Science, CSIR-Central Institute of Medicinal and Aromatic Plants, 2Restoration Ecology Group, CSIR-National Botanical Research Institute, Lucknow, India
Sodic soils are widely distributed in north India occupying about 1.6 Mha in Uttar Pradesh, which is 10% of the total cultivated area of the state. In this study, rehabilitation status of sodic land was compared through agroforestry system (Populus deltoides with medicinal plants) and monoculture plantations of Prosopis juliflora (leguminous) and Terminalia arjuna (non-leguminous). Tree density, basal area and standing biomass of P. deltoides was higher than monoculture plantations. Physicochemical [water holding capacity, bulk density, pH, electrical conductivity (EC), exchangeable sodium percentage (ESP), soil organic carbon (SOC), nitrogen, phosphorus], biological [microbial biomass, soil respiration, microbial quotient (Cmic: Corg), metabolic quotient (qCO2)] and biochemical [dehydrogenase, β-glucosidase, alkaline phosphatase, acidic phosphatase and protease] properties of soil were compared with unplanted sodic land. Soil bulk density, pH, EC, ESP and alkaline phosphatase decreased significantly, while other soil properties increased in rehabilitated systems irrespective of land use propositions. However, SOC was significantly higher (7.45 g kg-1) in agroforestry ecosystems than monoculture plantations i.e. 4.79 g kg-1 and 3.12 g kg-1 in T. arjuna and P. juliflora, respectively. The activities of soil enzymes, except alkaline phosphatase, were significantly higher in agroforestry system than monoculture plantations. Thus, agroforestry system with multiple cropping of medicinal plants showed maximum increase in soil fertility than monoculture plantations of either leguminous or non-leguminous species. The relationships of soil microbial biomass and enzyme activities were established with soil sodicity parameters (pH, EC, ESP and SAR) which indicate negative correlations, except alkaline phosphatase. The study concludes that agroforestry system is more efficient for rehabilitation of degraded sodic lands in comparison to monoculture plantations.