Hydrology and soil fertility of degraded grasslands at Cherrapunji in Northeastern India

Abstract

Four grassland types at Cherrapunji, in northeastern India, namely the Osbeckia, Arundinella, Ischaemum, and Eragrostiella, types, were studied for soil nutrient losses through their hydrology and related soil-fertility changes. Losses through water and the consequent soil-fertility depletion were shown to be related to the frequency of the burn to which these grasslands are subjected. The Ischaemum type, with regular burning at 2-years' intervals, was the most adversely affected, compared with the Osbeckia type, which had not been burnt for the past 6 years. In all the grassland types which were studied, the losses through water were high during the early part of the monsoon period, owing to the poor vegetation cover at that time. A desertified site with the Eragrostiella type of grassland had the lowest soil-fertility level, and had losses through removal in water that far exceeded the prevailing soil-nutrient level. Fire can help in stabilizing the seral grassland vegetation if the soil is sufficiently deep and the frequency of the burn is not too great. On the other hand, too frequent perturbations by fire are apt to result in a desertified landscape that is difficult to restore.