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Muneto?HirobeEmail author John?Sabang Balram K.?Bhatta Hiroshi?Takeda 《Journal of Forest Research》2004,9(4):347-354
The effects of tree species on the dynamics of nutrient transformations during leaf-litter decomposition are not well understood
in tropical rain forests. To examine differences in the dynamics of C, nutrients, and organic constituents during decomposition
among tree species, the leaf-litter decomposition of 15 trees was assessed using a litter-bag method in a lowland tropical
rain forest in Sarawak. The dynamics of C was parallel to that of weight loss. The dynamics of nutrients were grouped into
three patterns. The dynamics of K was characterized by a high leaching loss in the initial stages, and that of Ca and Mg generally
showed a gradual decrease over the course of decomposition. The dynamics of N and P showed highly different patterns with
the weight loss, and was characterized by relatively higher remaining mass at the end of the experiment. The variations or
exceptions of nutrient dynamics among tree species were considered to be related to the initial concentration of each nutrient.
For the dynamics of organic constituents, water-soluble carbohydrates disappeared quickly at the initial stages, and acid-soluble
carbohydrates were the second fastest decomposing fraction; the decomposition of acid-insoluble residue (AIS) was the slowest.
The release of limiting nutrients (N and P) generally followed the disappearance of AIS, but was independent of the disappearance
of AIS when the initial concentrations of these nutrients were very low. 相似文献
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Hirobe Muneto Sabang John Bhatta Balram K. Takeda Hiroshi 《Journal of Forest Research》2004,9(4):341-346
In a lowland tropical rain forest in Sarawak, leaf-litter decomposition and the initial litter chemistry of 15 tree species
were studied. During 13 months of field experiment, weight loss of litter samples was between 44% and 91%, and calculated
decomposition rate constants (k) ranged from 0.38 to 2.36 year−1. The initial litter chemistry also varied widely (coefficients of variation: 19%–74%) and showed low N and P concentrations
and high acid-insoluble residue (AIS) concentration. For nutrient-related litter chemistry, correlations with the decomposition
rate were significant only for P concentration, C/P ratio, and AIS/P ratio (r
s
= 0.59, −0.62, and −0.68, n = 15, P < 0.05, respectively). For organic constituents, correlations were significant for concentrations of AIS and total carbohydrates,
and AIS/acid-soluble carbohydrate ratio (r
s
= −0.81, 0.51, and −0.76, n = 15, P < 0.05, respectively). These results suggested that the relatively slow mean rate of decomposition (k = 1.10) was presumably due to the low litter quality (low P concentration and high AIS concentration), and that P might influence
the decomposition rate; but organic constituents, especially the concentration of AIS, were more important components of initial
litter chemistry than nutrient concentrations. 相似文献
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Joseph Jawa Kendawang Sota Tanaka Kenji Shibata Nanae Yoshida John Sabang Ikuo Ninomiya Katsutoshi Sakurai 《Soil Science and Plant Nutrition》2005,51(4):515-523
The effects of burning on the levels of soil organic matter, soil nitrogen, and soil microbial biomass were studied by carrying out experimental shifting cultivation at two sites, Niah and Bakam in Sarawak, Malaysia. Vegetation biomass was burned in plots (10 × 10 m2 ) at the rates of 0 (control), 100, 200, and 300 Mg ha−1 at the Niah site and 0, 20, and 100 Mg ha−1 at the Bakam site. At the Niah site, the levels of total C and N of the soils did not change throughout the experiment in spite of enhanced soil respiration until 2 months after burning. Although burning induced an increase in the amount of NH4 -N of the soils, the readily available pool of N (the sum of the NH4 -N, NO3 -N, microbial biomass N, and extractable organic N pools) in the burned plots was depleted appreciably at the end of rice cultivation. The effects of burning on these properties tended to be substantial with increasing amounts of the vegetation biomass burned. On the other hand, the levels of total C and N and the readily available N pool at the Bakam site were low before burning compared with those at the Niah site, and the burning treatments did not affect them appreciably. While the rice yield at the Niah site reached the average value obtained in traditional shifting cultivation in Sarawak, that at the Bakam site was much lower. It was suggested that the flush of NH4 -N induced by burning was one of the major factors for rice growth. 相似文献
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Daisuke Hattori John Sabang Sota Tanaka Joseph Jawa Kendawang Ikuo Ninomiya Katsutoshi Sakurai 《Soil Science and Plant Nutrition》2005,51(2):231-241
In order to provide appropriate soil information for the rehabilitation of tropical rainforest ecosystems, we examined the soil morphological, physico-chemical, mineralogical properties and charge characteristics in a degraded mixed dipterocarp forest with three type of vegetation, namely grassland, secondary forest, and remnant forest in Japan Sarawak Friendship Forest, Sarawak, Malaysia. We compared the soil properties at six representative locations differing in topography and vegetation types, with special reference to the effect of anthropogenic activities on the catenary sequence. All the soils were acidic or weakly acidic. Contents of clay, exchangeable Al, Alo, Ald and Fed and the values of the cation exchange capacity and Al saturation increased with depth. The clay mineral composition was dominated by kaolin minerals. The value of point of zero salt effect ranged from 3.0 to 4.0, indicating that the soil was not yet strongly weathered. A catenary sequence of the soils was observed; softer in soil hardness, higher contents of total exchangeable bases in the lower slope plots than in the upper slope plots and higher values of Feo/Fed in the surface horizon in the lower slope plots than in the upper slope plots. However, the effect of anthropogenic activities was observed; higher contents of total exchangeable bases in the grassland than in the other vegetation types. Based on the stable condition on weathering and erosion, the upper slope plot of the remnant forest exhibited a thicker O horizon, lower Feo/Fed values and a relatively high amount of chlorite. Soil variability should be taken into account for appropriate management of rehabilitation in tropical rainforests. 相似文献
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