Effect of Tree Leaf Litterfall on available Nutrients and Organic Carbon Pools of Soil

Abstract

A study was conducted to investigate the effect of leaf litterfall of shelterbelt, Azadirachta indica, Ailanthus excels and Prosopis cineraria and control (devoid of trees) on available nutrients and organic carbon pools of soil from 3 distances (2, 5 and 10m) The total litterfall during the study period ranged between 1712 and 4126kg/ha and it was found maximum in the month of January and it was minimum in February in different plantations. Annual litterfall showed considerable variation among different plantations. Litter accumulation under the different plantations canopy was highest in the shelterbelt followed by Prosopis cineraria and lowest in the Azadirachta indica. There was improvement in soil organic carbon, dissolved organic carbon, microbial biomass carbon, available macro (N, P and K) and micronutrients (Zn, Fe, Mn and Cu) tree species when compared to field without trees. Significant improvement in soil organic carbon (0.14 to 0.26 %), available N (55.9 to 116.6kg/ha) P (9.6 to 13.6kg/ha) and K (188.9 to 248.3kg/ha) was observed under these tree species compared to field without trees. The content of Zn, Cu, Fe and Mn and was 15, 25, 40 and 51 percent, respectively higher under these tree species than the control field. The amount of nutrients returned to the soils through litter was significantly highest at 2m distance under different plantations. The present study indicated that these available nutrients and organic carbon pools improved significantly across the different land use system. Due to intensive cultivation and monocropping, the fertility of soil is deteriorating day by day. Simultaneously it is creating a pressure on the natural resources like soil because the population is increasing day by day. Therefore, it is wise to use degraded and problematic soil for cultivation. Agroforestry systems have been recognized as an alternative for the rehabilitation of degraded areas and it provides ecosystem services and reduces human impacts on natural forests (Nair et al., 2009). Tree based land use systems have special role in reclamation of wastelands, use of poor-quality waters, organic carbon build up and moderating climate change related risks. In areas of Haryana and Rajasthan trees like Prosopis cineraria, Azadirachta indica and Ailanthus excels are more beneficial under adverse environments due to their drought hardiness, resistance to inhospitable climate and assured economic returns. These tree species can be grown on soils having poor fertility, moisture deficit and high soil temperature.