Eighteen clones of Eucalyptus tereticornis （Sm.） were evaluated for three years by adopting randomized block design for various growth parameters at Hoshiarpur, Punjab, India and compared with two checks. Significan...Eighteen clones of Eucalyptus tereticornis （Sm.） were evaluated for three years by adopting randomized block design for various growth parameters at Hoshiarpur, Punjab, India and compared with two checks. Significant variations were recorded for height, diameter at breast height （DBH） and clear bole height （CBH）. The broad sense heritability was low to moderate for both height and CBH. The genetic gain for height and CBH increased substantially pe se with the increase in age of trees. The average genetic gain for thres years was recorded maximum for height （159.60%） followed by DBH （110.97%） and CBH （70.34%）. Clone 17 attained maximum DBH over other genotypes for second and third year followed by clones 14 and 11. Clone 5 showed an upward trend for DBH and maintained its superiority for CBH as the age of the tree increased. Similarly, clone 11 changed its ranking from 9th to 8th to 3rd for DBH and from 9th to 4th to 2nd for CBH, respectively for the age of one, two and three years. Nonetheless, clones 6 and 10 per- formed poorly for all the characters studied. Clones 17, 14 and 5 were found to be the most promising clones for commercial deployment.展开更多
Low nitrogen (N) availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations (two plantations of E. tereticornis on the coastal lowlands, and tw...Low nitrogen (N) availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations (two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India) to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N fertilizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C:N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites (R2=0.92, p<0.01), and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.展开更多
Low nitrogen （N） availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations （two plantations of E. tereticornis on the coastal lowlands, and...Low nitrogen （N） availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations （two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India） to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N ferti- lizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C：N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites （R^2=0.92/ p〈0.01）, and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.展开更多
Two fast-growing Indian species, Melia composita Benth. and Eucalyptus tereticornis Sm., which have different sets of physical properties, were dried together in a vacuum press dryer(VPD) under two drying conditions,i...Two fast-growing Indian species, Melia composita Benth. and Eucalyptus tereticornis Sm., which have different sets of physical properties, were dried together in a vacuum press dryer(VPD) under two drying conditions,i.e., above boiling point(ABP) and below boiling point(BBP). The ABP and BBP conditions were maintained by keeping the temperature constant at 75 ℃ and maintaining two pressure levels: 300 mm of Hg(ABP) and 450 mm of Hg(BBP). In order to understand pressure conditions at the core during vacuum drying, a cylindrical brass pipe was inserted in both wood cores and attached with pressure gauges placed outside of the VPD. The results indicate that the Melia wood core attained equilibrium pressure immediately with the pressure of VPD, while Eucalyptus attained it very slowly, reaching equilibrium at later stages of drying when cracks and checks advanced to the core.The drying rate was higher for Melia than Eucalyptus under both drying conditions. The drying rate of Melia(ABP) was higher than Melia(BBP), however, the drying rate for Eucalyptus(ABP) was not significantly different from the BBP drying rate.展开更多
文摘Eighteen clones of Eucalyptus tereticornis （Sm.） were evaluated for three years by adopting randomized block design for various growth parameters at Hoshiarpur, Punjab, India and compared with two checks. Significant variations were recorded for height, diameter at breast height （DBH） and clear bole height （CBH）. The broad sense heritability was low to moderate for both height and CBH. The genetic gain for height and CBH increased substantially pe se with the increase in age of trees. The average genetic gain for thres years was recorded maximum for height （159.60%） followed by DBH （110.97%） and CBH （70.34%）. Clone 17 attained maximum DBH over other genotypes for second and third year followed by clones 14 and 11. Clone 5 showed an upward trend for DBH and maintained its superiority for CBH as the age of the tree increased. Similarly, clone 11 changed its ranking from 9th to 8th to 3rd for DBH and from 9th to 4th to 2nd for CBH, respectively for the age of one, two and three years. Nonetheless, clones 6 and 10 per- formed poorly for all the characters studied. Clones 17, 14 and 5 were found to be the most promising clones for commercial deployment.
基金supported by the Australian Centrefor International Agricultural Research
文摘Low nitrogen (N) availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations (two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India) to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N fertilizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C:N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites (R2=0.92, p<0.01), and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.
文摘Low nitrogen （N） availability often results in reduced productivity of Eucalyptus plantations. We studied the response of four eucalyptus plantations （two plantations of E. tereticornis on the coastal lowlands, and two plantations of E. grandis in the upland region of the Western Ghats, Kerala, India） to N addition and related this response to seasonal N mineralization as well as other indices of N availability, in order to examine the utility of soil based indicators of N mineralization for predicting the response of eucalyptus growth to added N ferti- lizer. Several biochemical indicators were examined for their capacity to predict response to N fertilizer, including total soil N, soil C：N ratio, and N released during anaerobic and aerobic incubation. Results show that nitrogen fertilizer addition increased productivity across the 4 sites from 7% to 70%, N released during an aerobic incubation had the highest correlation with fertilizer response across the 4 sites （R^2=0.92/ p〈0.01）, and that Modelled seasonal soil N mineralisation was a poorer predictor of fertilizer response than N released during an aerobic incubation. Whilst some of these indicators are promising, they need wider validation and testing before they could be routinely applied.
基金part of M.Sc.dissertation under financial support from ‘‘Forest Research Institute(Deemed)University,Dehradun(India)’’
文摘Two fast-growing Indian species, Melia composita Benth. and Eucalyptus tereticornis Sm., which have different sets of physical properties, were dried together in a vacuum press dryer(VPD) under two drying conditions,i.e., above boiling point(ABP) and below boiling point(BBP). The ABP and BBP conditions were maintained by keeping the temperature constant at 75 ℃ and maintaining two pressure levels: 300 mm of Hg(ABP) and 450 mm of Hg(BBP). In order to understand pressure conditions at the core during vacuum drying, a cylindrical brass pipe was inserted in both wood cores and attached with pressure gauges placed outside of the VPD. The results indicate that the Melia wood core attained equilibrium pressure immediately with the pressure of VPD, while Eucalyptus attained it very slowly, reaching equilibrium at later stages of drying when cracks and checks advanced to the core.The drying rate was higher for Melia than Eucalyptus under both drying conditions. The drying rate of Melia(ABP) was higher than Melia(BBP), however, the drying rate for Eucalyptus(ABP) was not significantly different from the BBP drying rate.
