Determination of Deposition and Leaves in Teak Plantations in Thailand     

Jesada Luangjame  Boonchoob Boontawee  Nigorn Kliangpibool 《Water, air, and soil pollution》2001,130(1-4):935-940

This paper outlines the results to date of the continuing acidic deposition study from 1997 in three teak plantations at the Na Pralan, Klangdong, and Donglan villages of Thailand. The aim of this study was to examine the impact on teak plantations of acid deposition — the increasing flow of chemical compounds including CO₂, SO₂, NO₂, and NO_x into the atmosphere. The 1997–1999 results showed no symptoms of acidity of the precipitation in the teak plantations at the treated sites (Na Pralan and Klangdong). During this period, the pHs of stemflow and throughfall were still over 7; and the pHs of the rainfall were around 7, except at Klandong where it dropped to around 5 in 1999. The pH and EC values were higher at the polluted sites than at the control site; this may be attributed to contamination with lime dust from nearby industrial plants, including cement factories and quarrying mills. Fresh leaves were contaminated with Sulphur to quite high levels at the Na Pralan site. This contamination seems to have affected the physiology, biomass and chemical content of the leaves. It might be due to pollution gases (SO₂ and NO_x) from the heavy trucks on the nearby Phaholyothin road. However, these gases could not be detected by a gas detector even though pollution seemed quite heavy. This study did not detect acid rain damage to the teak plantations.  相似文献   

Seasonal and spatial variation of nitrogen dynamics in the litter and surface soil layers on a tropical dry evergreen forest slope     

Naoyuki Yamashita  Seiichi Ohta  Hiroyuki Sase  Jesada Luangjame  Thiti Visaratana  Bopit Kievuttinon  Hathairatana Garivait  Mamoru Kanzaki 《Forest Ecology and Management》2010

Seasonal and spatial variability of litterfall and NO₃⁻ and NH₄⁺ leaching from the litter layer and 5-cm soil depth were investigated along a slope in a tropical dry evergreen forest in northeastern Thailand. Using ion exchange resin and buried bag methods, the vertical flux and transformation of inorganic nitrogen (N) were observed during four periods (dry, early wet, middle wet, and late wet seasons) at 15 subplots in a 180-m × 40-m rectangular plot on the slope. Annual N input via litterfall and inorganic N leached from the litter layer and from 5-cm depth soil were 12.5, 6.9, and 3.7 g N m⁻² year⁻¹, respectively, whereas net mineralization and the inorganic N pool in 0–5-cm soil were 7.1 g N m⁻² year⁻¹ and 1.4 g N m⁻², respectively. During the early wet season (90 days), we observed 82% and 74% of annual NO₃⁻ leaching from the litter layer and 5-cm soil depth, respectively. Higher N input via leaf litterfall in the dry season and via precipitation in the early wet season may have led to higher NO₃⁻ leaching rate from litter and surface soil layers during the early wet season. Large spatial variability in both NO₃⁻ vertical flux and litterfall was also observed within stands. Small-scale spatial patterns of total N input via litterfall were significantly correlated with NO₃⁻ leaching rate from the surface soil layer. In tropical dry evergreen forests, litterfall variability may be crucial to the remarkable seasonal changes and spatial variation in annual NO₃⁻ vertical flux in surface soil layers.  相似文献   

Effects of Photosynthetically Active Radiation and Air Temperature on CO2 Uptake of Pterocarpus macrocarpus in the Open Field     

Sureeporn Kerdkankaew  Jesada Luangjame  Pojanie Khummongkol 《中国农业科学(英文版)》2005,4(4)

Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmental conditions such as photosynthetically active radiation (PAR), temperature, water and nutrient contents. PAR is the most immediate environmental control on photosynthesis while air temperature affects both photorespiration and dark respiration. In the natural condition, PAR and temperature play an important role in net CO2 uptake. The effects of PAR and air temperature on the CO2 uptake of Pterocarpus macrocarpus grown in a natural habitat were studied in the present work. Due to many uncontrollable factors, a simple rectangular hyperbola could not represent the measured data. The data were divided into groups of 2℃ intervals; CO2 uptake in each group may then be related to PAR by a rectangular hyperbola function. Using the obtained functions, the effect of PAR was removed from the original data. The PAR-independent CO2 uptake was then related to air temperature. Finally, the effects of PAR (I) and air temperature (Ta) on the CO2 uptake rate (A) were combined as:A= [(-0.0575 Ta2+ 2.6691 Ta-23.264)I/(-4.8794Ta2+227.13Ta-2456.9)+I](-0.00766Ta2+0.40666Ta-3.99924)  相似文献