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The objectives of this study were to investigate effects of land use on accumulation of soil organic matter (SOM) in the soil profile (0–100 cm) and to determine pattern of SOM stock distribution in soil profiles. Soil samples were collected from five soil depths at 20 cm intervals from 0 to 100 cm under four adjacent land uses including forest, cassava, sugarcane, and paddy lands located in six districts of Maha Sarakham province in the Northeast of Thailand. When considering SOM stock among different land uses in all locations, forest soils had significantly higher total SOM stocks in 0–100 cm (193 Mg·C·ha−1) than those in cassava, sugarcane, and paddy soils in all locations. Leaf litter and remaining rice stover on soil surfaces resulted in a higher amount of SOM stocks in topsoil (0–20 cm) than subsoil (20–100 cm) in some forest and paddy land uses. General pattern of SOM stock distribution in soil profiles was such that the SOM stock declined with soil depth. Although SOM stocks decreased with depth, the subsoil stock contributes to longer term storage of C than topsoils as they are more stabilized through adsorption onto clay fraction in finer textured subsoil than those of the topsoils. Agricultural practices, notably applications of organic materials, such as cattle manure, could increase subsoil SOM stock as found in some agricultural land uses (cassava and sugarcane) in some location in our study. Upland agricultural land uses, notably cassava, caused high rate of soil degradation. To restore soil fertility of these agricultural lands, appropriate agronomic practices including application of organic soil amendments, return of crop residues, and reduction of soil disturbance to increase and maintain SOM stock, should be practiced.
Benjapon Kunlanit; Laksanara Khwanchum; Patma Vityakon. Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand. Applied and Environmental Soil Science 2020, 2020, 1 -15.
AMA StyleBenjapon Kunlanit, Laksanara Khwanchum, Patma Vityakon. Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand. Applied and Environmental Soil Science. 2020; 2020 ():1-15.
Chicago/Turabian StyleBenjapon Kunlanit; Laksanara Khwanchum; Patma Vityakon. 2020. "Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand." Applied and Environmental Soil Science 2020, no. : 1-15.
Benjapon Kunlanit; Frank Rasche; Aunnop Puttaso; Georg Cadisch; Patma Vityakon. Vertical dynamics of dissolved organic carbon in relation to organic input quality and microaggregate formation in a coarse- textured Ultisol. European Journal of Soil Science 2019, 71, 459 -471.
AMA StyleBenjapon Kunlanit, Frank Rasche, Aunnop Puttaso, Georg Cadisch, Patma Vityakon. Vertical dynamics of dissolved organic carbon in relation to organic input quality and microaggregate formation in a coarse- textured Ultisol. European Journal of Soil Science. 2019; 71 (3):459-471.
Chicago/Turabian StyleBenjapon Kunlanit; Frank Rasche; Aunnop Puttaso; Georg Cadisch; Patma Vityakon. 2019. "Vertical dynamics of dissolved organic carbon in relation to organic input quality and microaggregate formation in a coarse- textured Ultisol." European Journal of Soil Science 71, no. 3: 459-471.
Soil capacity as a major carbon (C) sink is influenced by land use. Estimates of soil organic carbon (SOC) sequestration have mostly focused on topsoils [0–30 cm official Intergovernmental Panel on Climate Change (IPCC) soil depth]. We investigated SOC stocks and their quality as influenced by land-use changes. Soil samples were collected from five soil depths down to 100 cm of three adjacent fields each representing a different land use—forest, cassava, and rice paddy—in Northeast Thailand. Sequestration of SOC in topsoils under all land uses was higher, as indicated by SOC stocks (59.0–82.0 Mg ha−1) than subsoils (30–100 cm) (27.0–33.0 Mg ha−1). The soil profile (0–100 cm) of the forest had higher stocks of SOC and humic acid (115.0 and 6.8 Mg ha−1, respectively) than those of cultivated land uses [paddy (100.0 and 4.8 Mg ha−1, respectively) and cassava (87.0 and 2.3 Mg ha−1, respectively)], which accounted for an average 30% increase in SOC sequestration over those with only topsoil. Topsoils of the forest had higher humic acid content but narrower E4:E6 ratio [the ratio of absorbances at 465 nm (E4) and at 665 nm (E6)] of humic acids (2.8), indicating a higher degree of humification and stabilization than the cultivated soils (3.2–3.6). Subsoil C was higher quality, as indicated by the lower E4:E6 ratio of humic acids than topsoils in all land uses.
Benjapon Kunlanit; Somchai Butnan; Patma Vityakon. Land–Use Changes Influencing C Sequestration and Quality in Topsoil and Subsoil. Agronomy 2019, 9, 520 .
AMA StyleBenjapon Kunlanit, Somchai Butnan, Patma Vityakon. Land–Use Changes Influencing C Sequestration and Quality in Topsoil and Subsoil. Agronomy. 2019; 9 (9):520.
Chicago/Turabian StyleBenjapon Kunlanit; Somchai Butnan; Patma Vityakon. 2019. "Land–Use Changes Influencing C Sequestration and Quality in Topsoil and Subsoil." Agronomy 9, no. 9: 520.