Mohinder Pal , D. P. Raturi

Abstract

The preeent Investigation waa undertaken to study the growth, biomass production, dry matter distributIon pattern and inter-relationship between the various yield contributes of biomass of Eucalyptus hybrid grown in an energy plantation, under rain-fed conditions In semi-acid zone. The age of plantation was three years. The growth of individual trees in the plantatIon was very heterogeneous. The tree height varied from 550 cm to 990 cm and girth at breast height varied from 5 cm to 35 cm. Although the larger trees, or category A trees, were much fewer in number than the medium size and smaller trees of category B and category C, their contribution to biomass yield was maximum. Further, the biomass of category A trees was superior even qualitatively since it contained higher percentage of bole-wood and utilizable biomass and less at non-utilizable biomass. The total blomsss yield was 44.78 oven-dry tonne per hectare. Bole and brenches constitute the major yield contributes of biomass.

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A. C. Gupta , D. P. Raturi

Abstract

Distribution of organic matter and plant nutrients in a 10 yearS old Eucalyptus hybrid plantation raised on lateritic soil in Mauza Barihote, Hoomgarh Range, East Midoapore Forest Division, West Bengal have been discussed. It seems that Eucalyptus hybrid is well suited for this tract when growth with adequate manuring. From the growth rate of this species on average type of soil the crop at the end of the first rotation can be expected to yield about 90 tonnes of usable nood per ha which should increase with better inputs and experience in raising these plantations.

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K. Gurumurti , M. M. Kimothi , D. P. Raturi , J. S. Rawat

Abstract

Studies on growth, assimilation rate, biomass production, solar energy conversion efficiency and seasonal energy conversion efficiency by Eucalypts under energy plantation practices (short spacing, 13m × 13m) have been carried out at six monthly intervals for a period of 36 months under semi-arid non-irrigated conditions in Gujarat. The results show that there exists considerable variation among the population of the trees which increase with increasing age. The total biomass ranged from 5 dt/ha at 12 months to 66 5 dt/ha at 36 months,the utilizable biomass (wood, bark, branch) ranging from 2.25 dt/ha to 43 5 dt/ha for the same periods. There existed a direct correlation between, the leaf biomass and total biomass by different categories of trees. The results on various growth parameters, viz,net assimilation rate, relative growth fate and crop growth fate is also presented. The relationship between D²H and total as well as utilizable dry malter production by trees has been worked out and presented. The solar energy conversion efficiency as found to be maximal at 36 months of the age being 126. The seasonal energy conversion efficiency showed two peaks, one 18-24 ond another 30-36 month., the values being 1.77 and 3.16 per cent of PAR coinciding with lhe period of moisture availability. The high biomass production by trees under energy plantation practices as related to the CO₂ profile and energy conversion efficiency is briefly discussed.

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K. Gurumurti , D. P. Raturi , H. C. S. Bhandari

Abstract

Studies on time trends of biomass production by means of age series in energy plantations (spacing 1.3 × 1.3 m) of Prosopis juliflora is presented. The component wise biomass production at the age of 18, 24, 30, 36 and 48 months was determined. The results show considerable variation among the population of trees. However, distinct linear relationship between girth at breast heighht (GBH) and total height was discernible. The total biomass produced at 18, 24,30,36 and 48 months of age was 19.69, 41.39, 69.11, 114.62 and 148.63 dry tonnes per hectare, respectively, the corresponding figures for utilizable biomass wood, bark and branch) were 14.63, 32.17, 50.59, 88.87 and 113.25 dry tonnes per hectare. At all the periods of study, branch component formed the major portion of total biomass being around 50 to 55 per cent utilizable biomass was three fourth of total biomass at all ages. The solar energy conversion efficiency ranged from 0.59 per cent at 18 months to 1.68 per cent at 48 months of age the peak value being 1.87 per cent at the age of 36 months. It is shown that the variable diameter and height can be used to reliably predict the biomass production in Prosopis juliflora with the help of the regression equations developed in the present study. It is cuncluded that Prosopis juliflora is an ideal candidate for energy plantations in semi arid and marginal lands, not only to meet the fuelwuod demands but also to improve the soil fertility, for, this plant is fast growing and nitrogen fixing leguminous tree.

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