摘要 : Attempts were made to develop a growth model for Acacia auriculiformis in relation to soil conditions. The growth model, based on unified approach, consisted of five modules such as effects of site index, unrestrained growth, agin... 展开 Attempts were made to develop a growth model for Acacia auriculiformis in relation to soil conditions. The growth model, based on unified approach, consisted of five modules such as effects of site index, unrestrained growth, aging, density of A. auriculiformis and density of miscellaneous species. The model was calibrated based on the data gathered from fifty semi-permanent sample plots established in A. auriculiformis plantations in the State of Kerala, India. The parameters of the growth functions were estimated using PROC MODEL of SAS, with iterated generalized method of moments. Girth at breast-height (1.37 m above ground) was recorded on all the trees in the plots. Height was measured on a sub sample trees. The measurements were recorded for two successive years. Diameter increment and volume (in terms of commercial, pulpwood, timber over-bark and timber under-bark) increment were computed for all the 50 plots. The soil samples collected from each plot were subjected to physical and chemical analyses to determine texture, pH, electrical conductivity, organic carbon, available N, P, K, exchange acidity, exchangeable Al, Ca, Mg and available Fe, Cu, Zn and Mn using standard procedures. In the growth model, K in 10-20 cm depth level alone turned out as the foremost soil variable significantly influencing tree growth. The adjusted R² value for the diameter increment function was 0.70 and almost 0.90 for all the volume increment functions, reasonable values to expect under natural conditions. However, this implies that a remaining variation in growth happens on account of factors not included in the model. The results also indicate a positive increase in the soil K in 10-20 cm layer with increase in diameter growth, keeping other factors constant. The growth model developed is more reliable on account of the biological validity. 收起