Soil Nutrients and Fertility in Three Traditional Land Use Systems of Khonoma, Nagaland, India

摘要

Status of soil nutrients and fertility was studied in three traditional land use systems viz Natural Forest (NF); Alder based Jhum Fallow (JF) and Wet Terrace Paddy cultivation (PF) in Khonoma, Nagaland located in North- East India. Soil samples were collected from the three sites and soil fertility indicators such as pH, mineralizable Nitrogen (N), available Phosphorus (P), available Potassium (K), Soil Organic Carbon (SOC) and Soil Organic Matter (SOM) were analyzed using standard procedures. The soil of Natural Forest was found to be most fertile based on the calculated Nutrient Index followed by Alder based Jhum Fallow and Paddy Fields. The analysis of variance (ANOVA) showed significant (P< 0.05) differences among the three land use types with regard to the soil nutrients studied. These results showed that land use types have significant effect on soil nutrients and thus its fertility. Continuous agricultural activities deplete soil fertility, but by maintaining a period of fallow this decrease in soil fertility is reclaimed. The rate of reclamation from a nutrient deficient condition to nutrient rich condition is found to be enhanced in the study site by growing and maintaining Alnus nepalensis D Don, more popularly known as the Alder tree. This is evident from the present study of soil nutrients from 2-5 years old jhum fallows showing soil properties ranging between soils of paddy fields and Natural Forest. The study thus establishes that land use should be chosen with care to preserve the quality of the soil.