GROWTH, BIOMASS ESTIMATIONS AND FUEL QUALITY EVALUATION OF COPPICE PLANTS OF <em>PROSOPIS</em> <em>JULIFLORA</em> ON SODIC SOIL SITE

Abstract

3.5-y-old coppice trial of Prosopis juliflora was evaluated for wood fuel production on a highly alkaline soil site (pH > 8.7). Initially coppice plants showed emergence of 11.7 ± 5.1 sprouts per stump followed by dominance of 3.7± 0.7 shoots per stump after 42 months of growth. Dominant shoots attained an average height of 470 ±133 cm and a diameter of 3.4 ± 1.5 cm at 50cm from ground level. Linear regression equation [y=a+ b(nd²h), measurement of height and diameter of the most dominant shoot and counting number of coppice shoots per plant] was found to be the best predictor of biomass because of high correlation coefficient and significance of regression coefficients (p<0.001, p<0.01). Equations using height or diameter alone had relatively poor functional correlation. At the age of 3.5 y, coppice plants produced a total of 82.7 t ha^-1 green biomass with nearly 90% biomass allocation to stems (43.2 t ha^-1) was maximum followed by branch wood (18.7 t ha^-1) and leaves (2.15 t ha^-1) respectively. Fuel quality of coppice plants assessed on the basis of wood fuel value index (607 ± 65.7 to 1518 ± 81.8) and biomass-ash ratio (29 to 37) varied greatly depending on shoot thickness. The study shows the potential of coppice system in P. juliflora to obtain quality fuelwood under short rotation harvest (<4 y) on sub-standard soil sites.