RAINWATER CONSERVATION AND USE BY AN ENERGY PLANTATION OF <em>EUCALYPTUS</em> <em>TERETICORNIS</em> AND RAINFED FIELD CROPS IN NORTH INDIA

Abstract

In an attempt to study the prospects of developing alternative bioenergy sources to petroleum products, a short duration, high density (10,000 trees ha^-1) energy plantation of Eucalyptus tereticornis was raised on a typical sandy loam soil at the foot-hill of north India. The efficiency of rainwater conservation and use was compared with sesame - rapeseed crop raised in the other half of the same field with identical site conditions. The 300 cm deep soil profile of the agricultural land use system (ALUS) conserved 45, 84 and 181mm and that of the forestry land use system (PLUS) conserved 311, 240 and 445 mm of water from the monsoon rainfall of 685, 905 and 1586 mm recorded in 1985, 1986 and 1988 respectively. The respective mean gains were 68 and 244 TOM of water. The exceptional drought of 1987 produced no net gain for either system. The monsoon rainfall recharged the soil profile up to a depth of 150 cm in the ALUS but up to 240-300 cm depth in the FLUS. The annual water uses were 774, 806,417 and 816mm for the ALUS, and 976, 1062, 435 and 1141 mm for the FLUS in 1985-86, 1986-87, 1987-88 and six months of 1988-89 respectively. The mean annual and total water uses were 801 and 2803 mm respectively for the ALUS, and 1033 and 3614 mm.respectively for the FLUS. The profile water content at the end of the study was the same for both systems. The FLUS used 29% extra water by conserving rainwater which was wasted by the ALUS as runoff. The FLUS increased soil moisture deficits in deeper soil layers before and between the monsoon rainfall events resulting in high infiltration. Eucalyptus was a relatively more efficient user of rainwater than field crops.