MACRONUTRIENT DYNAMICS AND USE EFFICIENCY IN THREE SPECIES OF SHORT ROTATION FORESTRY DEVELOPED ON SODIC SOILS IN NORTH INDIA

Abstract

Macronutrient dynamics and nutrient-use efficiency were investigated in young plantations of three fuelwood species established on a degraded sodic soil in Lucknow in north India (26° 45' N, 80° 51' E). The purpose was to generate fuelwood in short rotations on community wastelands of this region. Of the three species studied, aboveground production of mesquite, Prosopisjuliflora was greater than Acacia nilotica and Terminalia arjuna during the six years of their growth span. In general nutrient (N, P, K, Ca and Mg) concentrations were greater in P. juliflora than in A. nilotica and T. arjuna, particularly in foliage component. There were little variations in woody components between the species. Prosopis juliflora stand had greatest nutrient capital followed by A. nilotica and. T. arjuna. Nutrient fluxes (uptake, retention, retranslocation and return) were also relatively high in the Prosopis stand. Acacia nilotica had the
greatest N-, K-, Ca- and Mg-use efficiencies. P-use efficiency was lowest in A. nilotica. Nutrient cost of wood production and removal indicated that one tonne of wood can be produced at the cost of minimum nutrient economy by A. nilotica. As a result of these plantations, the net effects on soil properties showed significant reductions in soil bulk density, pH and exchangeable sodium percentage after six years. Conversely, organic C, total N, exchangeable Ca and Mg increased in the soil, whereas K status remained almost constant. Prosopis juliflora reclaimed the soil more efficiently in comparison with the other species.