• Corpus ID: 157059881

Hydrological Implications of Planting Bluegum in Natural Shola and Grassland Watersheds of Southern India

@inproceedings{Samra2001HydrologicalIO,
  title={Hydrological Implications of Planting Bluegum in Natural Shola and Grassland Watersheds of Southern India},
  author={Jagir Singh Samra and Alok Kumar Sikka and Vishwa Nath Sharda},
  year={2001}
}

• J. Samra, A. Sikka, V. N. Sharda
• Published 2001

*J.S. Samra, Indian Council of Agricultural Research, Krishi Bhawan, New Delhi-110 001 India; A.K. Sikka, Central Soil & Water Conservation Research & Training Institute, Research Centre, Udhagamandalam – 643 004, India; and V.N. Sharda, Central Soil & Water Conservation Research & Training Institute, Dehra Dun 248 195, India. *Corresponding author: [e-mail]. ABSTRACT The paper presents the results of a long term (196892) experimental watershed study conducted by Central Soil & Water Conservation Research & Training Institute, Research Center, Udhagamandalam at Glenmorgan in Nilgiris on the hydrological implications, tree growth and economics of planting Eucalyptus globulus (bluegum) in a natural mixed “Shola” and grassland forest watershed following the paired watershed technique. Grassland area of 18.7 ha (59%) of a watershed was replaced with bluegum in one of the two comparable watersheds of about 32 ha each during 1972, after a calibration period of 4 years (1968-71). Ten years rotation cycle was followed for harvesting and coppice regeneration. Average annual reduction in water yield of the order of 16% and 25.4% was determined from the bluegum watershed over the natural grassland during the first and second rotation, respectively. Maximum reductions in runoff were observed during July to October and this was attributed to greater availability of rainfall and hence its utilization during this period. Appreciable reduction in low flow as a result of decline in base flow could be predicted with Low Flow Index (LFI) decreasing by 2.0 and 3.75 times, in the first and second rotation, respectively. This dry period flow, though small, is very crucial for sustaining water supply to hydroelectric reservoirs. Moderation in peak discharge rates was also observed as a result of bluegum plantation. The biomass and economic returns for the second rotation were also 42 per cent and 40 per cent higher than the first rotation, but at a cost of 60% more reduction in water yield during the second rotation over the first rotation. The coppiced bluegum depleted soil moisture from deeper soil layer whereas during the first rotation, the extraction was mostly confined to the surface layers.