Forest Soil Research 

1. The Soil Profile Figure and Soil Fertility Status at Nong Koo Gene Conservation Station, in Sang Kha District, Surin Province
2. Site Sustainability of the Mixed Species Planting, Eucalypt/Acacia II. The Study on Nitrogen and Phosphorus Accumulation in the Leaf and Leaf Litter of Eucalyptus camaldulensis  and Acacia auriculiformis in Mixed Species Stand
3. Evaluation of Leguminous Tree Species Using as Soil Improver at Nhong Koo Gene Conservation Center in Surin Province
4. Change of Soil Properties after 10 Years Forest Plantation

By… Siripa Phopinit, Sirirat Jamahasatien and Mayuree Wannapinit

ABSTRACT

A study on soil profile figure and soil fertility status was conducted at Nong Koo Gene Conservation Station in Sang Kha District, Surin Province which was classified into two soil groups, Regosal great soil group and Low humic gley great soil group. A preliminary survey was done over the area by using soil auger for selecting the representative of each soil group. On each site, a hole was dug for describing the soil profile characteristics such as; soil texture,soil colour, soil structure, soil pH, soil horizon and plant root distribution as well. A set of soil samples was collected for analyzing chemical and physical properties. The result showed that both types of soil are alluvial soil. Regosal great soil group was found at slope 3 percent with 24 centimeter depth of upper soil while Low humic gley great soil group was found at slope 0-2 percent with much deeper of upper soil or about 40 centimeter. However, both soil types are evaluated as low fertility level, the organic matter in lower horizon of the Low humic gley great soil group was greater than that of the Regosal great soil group.

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รายงานวนวัฒนวิจัย ประจำปี 2542 ส่วนวนวัฒนวิจัย สำนักวิชาการป่าไม้ หน้า 68-79

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By… Wilawan Wichiennopparat, Partap K. Khanna and Pornpun Jongsuksuntigool

ABSTRACT

The study on nitrogen (N) and phosphorus (P) accumulation in the green foliage, senescent leaves and leaf litter on the forest floors of Eucalyptus camaldulensis and Acacia auriculiformis in mixed species plantation was carried out at 2 experimental sites, Paktor Experimental Station, Ratchaburi province and Ladkrating Plantation, Chachoengsao province. The plantation contained five mixtures and two planting densities. The study of initial soil status at 2 sites showed differences in various soil characteristics, particularly, in the levels of available P (3.56-4.17 mg/kg in 2 m x 4 m plots and 6.74-9.32 mg/kg in 2 m x 2 m plots at Chachoengsao site and 31.57-34.06 me/kg in 2 m x 4 m plots and 22.66-27.08 mg/kg in 2 m x 2 m plots at Rachaburi site). This reflected in the amount of P found in green foliage at both sites, but not significantly had any influence on growth 27.08 mg/kg in 2 m x 2 m plots at Rachaburi site). This reflected in the amount of P found in green foliage at both sites, but not significantly had any influence on growth performance of either species at 22 months after planting. The amounts of N and P found in the senescent leaves and leaf litter obviously decreased due to the withdrawal process. The total amount of N returned to the soil through decomposition in each treatment at both sites at 18 months after planting ranged from 3.47 to 11.68 kg/ha and 8.65 to 12.35 kg/ha at Ratchaburi site and Chachoengsao site respectively and the amount of P ranged from 0.10 to 0.26 kg/ha and 0.42 to 0.59 kg/ha at Ratchaburi site and Chochoengsao site respectively.

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รายงานวนวัฒนวิจัย ประจำปี 2542 ส่วนวนวัฒนวิจัย สำนักวิชาการป่าไม้ หน้า 53-67

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By… Pornpun Jongsuksuntigool and Visal Lertnitiwong

ABSTRACT

This study was attempt to find leguminous tree species that could be used for improving the condition of poor soil named Regosol soil (Typic Quartzipsamments soil) at Nhong Koo Gene Conservation Center in Sungkha district, Surin province. It was conducted for 10 years from 1990 to 1999. Four native species (Xylia xylocarpa, Cassia siamea, Peltophorum pterocarpum and Tamarindus indica) and four exotic species (Acacia auriculaeformis, Leucaena leucocephala, Pithecellobium dulce and Acacia mangium) were evaluated. The randomized complete block design with 9 treatments (8 legume tree species and control) and 3 replications was done. The spacing between plants and between rows were 2x2 m.The soil samples of 0-5, 5-10, 10-20 and 20-40 cm. depths were analyzed for two times during the study, at the 4^th year (3 year-old tree) and the 10^th year (9 year-old tree). The tree growth characteristics with its survival and the change of soil chemical properties were evalulated, accordingly. Various experiments were studied to find the effects of legume trees on soil conditions. The parameter studied were the annual amount of leaf litter, the nutrient content of leaf litter, the annual decomposition rate of leaf litter, the content of nutrients released from leaf litter decomposition, the nitrogen mineralization in top soil and the annual amount of nutrients in surface soil.

From the results, the tree growth characteristics with its survival and the change of soil conditions were properly evaluated at the 10^th year (or 9 year-old tree). It appeared that there were only 5 out of 8 species showed over 75% survival rate and satisfaction for the growth characteristics of the studied site. The best growth performance was A. mangium, followed by A. auriculaeformis, P. pterocarpum, C. siamea and X. xylocarpa, respectively. The general condition of soil chemical characteristics was best in soil under C. siamea, followed by P. pterocarpum, A. auriculaeformis, A. mangium and X. xylocarpa, respectively. It appeared that the chemical characteristics of top soil (0-10 cm. depth) under each species and bare land (control treatment) were shown as followed. The soil under C. siamea had pH 4.01, O.M. 0.87%, N 64.97 mg/100g, P 3.13 ppm, K 0.031 me/100g, Ca 0.240 me/100g, Mg 0.097 me/100g, C.E.C. 2.65 me/100g and B.S. 14.31%; the soil under P. pterocarpum had pH 3.86, O.M. 0.95 %, N 45.30 mg/100g, P 1.49 ppm, K 0.025 me/100g, Ca 0.152 me/100g, Mg 0.132 me/100g, C.E.C. 2.86 me/100g and B.S. 10.78 %; the soil under A. auriculaeformis had pH 3.75, O.M. 1.25 %, N 40.67 mg/100g, P 2.90 ppm, K 0.025 me/100g, Ca 0.120 me/100g, Mg 0.074 me/100g, C.E.C. 2.79 me/100g and B.S. 8.53 %; the soil under A. mangium had pH 3.86, O.M. 1.00 %, N 39.32 mg/100g, P 2.16 ppm, K 0.026 me/100g, Ca 0.138 me/100g, Mg 0.070 me/100g, C.E.C. 2.76 me/100g and B.S. 9.97 % ; the soil under X. xylocarpa had pH 3.71, O.M. 0.67 %, N 81.30 mg/100g, P 1.94 ppm, K 0.019 me/100g, Ca 0.095 me/100g, Mg 0.073 me/100g, C.E.C. 3.11 me/100g and B.S. 7.28 % and the bare land soil had pH 3.71, O.M. 0.42%, N 27.11 mg/100g, P 1.06 ppm, K 0.013 me/100g, Ca 0.106 me/100g, Mg 0.035 me/100g, C.E.C. 2.46 me/100g and B.S. 8.21%.

The species seemed to be suitable for using as soil improver were C. siamea, P. pterocarpum, A. auriculaeformis, A. mangium and X. xylocarpa, respectively. If wood utilization and soil improving are concerned, however, A. mangium, A. auriculaeformis, P. pterocarpum, C. siamea and X. xylocarpa are recommended.

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รายงานวนวัฒนวิจัย ประจำปี 2542 ส่วนวนวัฒนวิจัย สำนักวิชาการป่าไม้ หน้า 35-52

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Forest Tree Improvement Research  |   Forest Tree Seed Management and Research  |   Forest Plantation Research   |  
Forest Soil Research  |  Biotechnology and Biochemistry Research  |   Field Silvicultural Research  |