排序方式： 共有7条查询结果，搜索用时 15 毫秒
1
1.
2.
Hardjono?Arisman Susumu?KurinobuEmail author Eko?Hardiyanto 《Journal of Forest Research》2004,9(3):233-237
A minimum-distance boundary method that will minimize the sum of distances between measured points and a fitted self-thinning lines on log–log coordinates of stand density and quadratic mean diameter was proposed in order to estimate the maximum size density line: an upper boundary of self-thinning line. The lines for A. mangium were inferred with this method using data in two areas of unthinned plantations in South Sumatra, Indonesia. Slopes of the lines were deduced as –1.63 and –1.67 within the range of 10–21cm of quadratic mean dbh. The intensity of self-thinning was examined as a rate of reduction of density in relation to dbh increment. The rates were found to be higher than the slopes in the range close to the maximum line; hence the lines inferred in this study were likely existent. Maximum basal area deduced from the size-density line was 28–30m2/ha at 12cm of dbh and then it increased up to 34–37m2/ha at 20cm of dbh. 相似文献
3.
Taiki Mori Seiichi Ohta Shigehiro Ishizuka Ryota Konda Agus Wicaksono Joko Heriyanto Arisman Hardjono 《Biology and Fertility of Soils》2013,49(1):13-21
An incubation experiment was conducted to examine the effects of phosphorus (P) addition with and without ammonium, nitrate, or glucose on N2O and NO emissions from soil taken under Acacia mangium plantation and incubated at 100 % water-filled pore space (WFPS). Additions of NO 3 ? stimulated the N2O and NO emissions while NH 4 + did not, showing that denitrification was the main process of N2O and NO production in the study condition. When NO 3 ? was added with P significantly (P?<?0.05) increased N2O emissions regardless of the ratio of the added nitrogen and carbon, suggesting that P addition stimulated denitrification activity. The activation of denitrification by P addition is possibly attributed to two mechanisms: (1) the added-P stimulated denitrification by relieving P shortage for denitrifying bacteria and (2) the added-P stimulated activity of heterotrophic soil microflora with increased O2 consumption promoting the development of anaerobic conditions with stimulation of denitrification. 相似文献
4.
Acacia plantation establishment might cause soil acidification in strongly weathered soils in the wet tropics because the base cations in the soil are translocated rapidly to plant biomass during Acacia growth. We examined whether soils under an Acacia plantation were acidified, as well as the factors causing soil acidification. We compared soils from 10 stands of 8-year-old Acacia mangium plantations with soils from 10 secondary forests and eight Imperata cylindrica grasslands, which were transformed into Acacia plantations. Soil samples were collected every 5–30 cm in depth, and pH and related soil properties were analyzed. Soil pH was significantly lower in Acacia plantations and secondary forests than in Imperata grasslands at every soil depth. The difference was about 1.0 pH unit at 0–5 cm and 0.5 pH unit at 25–30 cm. A significant positive correlation between pH and base saturation at 0–20 cm depth indicated that the low pH under forest vegetation was associated with exchangeable cation status. Using analysis of covariance (ANCOVA), with clay content as the covariate, exchangeable Ca (Ex-Ca) and Mg (Ex-Mg) stocks were significantly lower in forested areas than in Imperata grasslands at any clay content which was strongly related to exchangeable cation stock. The adjusted average Ex-Ca stock calculated by ANCOVA was 249 kg ha−1 in Acacia plantations, 200 kg ha−1 in secondary forests, and 756 kg ha−1 in Imperata grasslands at 0–30 cm. Based on a comparison of estimated nutrient stocks in biomass and soil among the vegetation types, the translocation of base cations from soil to plant biomass might cause a decrease in exchangeable cations and soil acidification in Acacia plantations. 相似文献
5.
Yusuke Hagiwara Takashi Osono Seiichi Ohta Agus Wicaksono Arisman Hardjono 《Journal of Forest Research》2012,17(1):51-57
Colonization of leaf litter by ligninolytic fungi and relationships between mass loss and chemical qualities of surface leaf
litter were examined in Acacia mangium plantations and adjacent secondary forests in southern Sumatra Island, Indonesia. Leaves were collected from eight A. mangium plantations of different ages and three secondary forests. Partly decomposed leaves beneath the surface leaf litter were
used to measure the bleached area which indicated colonization by ligninolytic fungi. Surface leaf litter was used to measure
initial chemical content and subjected to the pure culture decomposition test. The bleached area was greater in secondary
forests than in A. mangium plantations. Nitrogen content was higher in all the A. mangium plantations than in the secondary forests, and acid unhydrolyzable residue (AUR) content was generally higher in the A. mangium plantations than in the secondary forests. The bleached area of leaf litter was negatively correlated with nitrogen content
of surface leaf litter at all sites, indicating an inhibition of the colonization by ligninolytic fungi of leaves with higher
nitrogen content. In a pure culture decomposition test inoculating a ligninolytic fungus to surface leaf litter, mass loss
of leaves was negatively correlated with AUR content of surface leaf litter. Mass loss of leaves and AUR was not significantly
related to nitrogen content. These results suggested that higher nitrogen content in A. mangium leaf litter had a negative effect by colonization of ligninolytic fungi, but the effect of high N in A. mangium leaf litter on the decomposition of leaf litter and AUR remained unsolved. 相似文献
6.
A simple step-wise procedure for predicting the course of stand development on log–log coordinates of stand density and quadratic mean diameter was presented based on a distance of measurement from the maximum size–density line of Acacia mangium. This procedure first predicts annual increment of diameter with a multiple linear regression having the distance, site index, and current diameter as independent variables, and then the associated mortality is calculated with the rate of reduction in stand density to the diameter growth derived from a fitted trend with the distance. The cumulative predictions, starting at 3 years after planting until 9 years of age, agreed well with the observations of group-age means of measurements calculated for the three levels of initial density. Contrasting trend of basal area growth between the three levels of initial density and those for their site index: the differences were decreasing in the former while they remained constant in the latter, was clearly illustrated with the procedure indicating a good potential for use in yield prediction. The simulations for stand growth under different spacing and thinning options were demonstrated in a stand density control diagram suggesting reasonable flexibility for practical application. 相似文献
7.
Ryota Konda Seiichi Ohta Shigehiro Ishizuka Seiko Arai Saifuddin Ansori Nagaharu Tanaka Arisman Hardjono 《Soil biology & biochemistry》2008,40(12):3021-3030
We investigated spatial structures of N2O, CO2, and CH4 fluxes during a relatively dry season in an Acacia mangium plantation stand in Sumatra, Indonesia. The fluxes and soil properties were measured at 1-m intervals in a 1 × 30-m plot (62 grid points) and at 10-m intervals in a 40 × 100-m plot (55 grid points) at different topographical positions of the upper plateau, slope, and valley bottom in the plantation. Spatial structures of each gas flux and soil property were identified using geostatistical analysis. The means (±SD) of N2O, CO2, and CH4 fluxes in the 10-m grids were 0.54 (±0.33) mg N m−2 d−1, 2.81 (±0.71) g C m−2 d−1, and −0.84 (±0.33) mg C m−2 d−1, respectively. This suggests that A. mangium soils function as a larger source of N2O than natural forest soils in the adjacent province on Sumatra during the relatively dry season, while CO2 and CH4 emissions from the A. mangium soils were less than or consistent with those in the natural forest soils. Multiple spatial dependence of N2O fluxes within 3.2 m (1-m grids) and 35.0 m (10-m grids), and CO2 fluxes within 1.8 m (1-m grids) and over 65 m (10-m grids) was detected. From the relationship among N2O and CO2 gas fluxes, soil properties, and topographic elements, we suggest that the multiple spatial structures of N2O and CO2 fluxes are mainly associated with soil resources such as readily mineralizable carbon and nitrogen in a relatively dry season. The soil resource distributions were probably controlled by the meso- and microtopography. Meanwhile, CH4 fluxes were spatially independent in the A. mangium soils, and the water-filled pore space appeared to mainly control the spatial distribution of these fluxes. 相似文献
1