CHANGES IN SOIL ORGANIC MATTER AND NITROGEN FERTILITY DURING THE SLASH-AND-BURN AND CROPPING PHASES IN EXPERIMENTAL SHIFTING CULTIVATION
スポンサーリンク
概要
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At the experimental field for the study of shifting cultivation set up in the forest of Iriomote Island in Okinawa, changes in pH, organic matter, and nitrogen fertility of soils after forest clearing by burning and during crop cultivation were investigated. The soils were sampled at six periods, I (before forest clearing), II (immediately before burning), III (immediately after burning), IV, V, and VI (10, 20, and 30 months after burning). Tilled and nontilled and other treatment plots were laid out, and cassava was grown twice. Soil pHs rose from periods I to III or IV, and then decreased. Carbon and nitrogen contents, the amounts of mineralizable nitrogen and nitrogen mineralization percentages decreased during cultivation. The amounts of humic and fulvic acids increased from periods I to II and decreased afterwards. The increase in NH_4-N due to the soil-burning effect was observed. The changes in the above-mentioned parameters during the cultivation period were greater for the first layer (0-5 cm) than for the second layer (5-10 cm), and for the tilled plots than for the non-tilled plots. The nitrification percentages which were originally very low, tended to increase with the rise of soil pH, and became very high after period III. Out of 11 soil samples taken at period III, two samples at the reburnt spots showed remarkable differences in carbon and nitrogen contents, nitrogen fertility, and humus composition compared with the others. Rp type humic acid was transformed into B or A type by reburning.
- 社団法人日本土壌肥料学会の論文
著者
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Ohta S
Faculty Of Agriculture Nagoya University
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Ohta Seiichi
Faculty Of Agriculture Nagoya University
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KUMADA Kyoichi
Faculty of Agriculture, Nagoya University
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ARAI Shigemitsu
Faculty of Agriculture, Nagoya University
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KITAMURA Masaji
Faculty of Agriculture, Nagoya University
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IMAI Katsuhiko
Faculty of Agriculture, Nagoya University
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Imai Katsuhiko
Faculty Of Agriculture Nagoya University
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Kumada Kyoichi
Faculty Of Agriculture And Water Research Institute Nagoya University
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Arai Shigemitsu
Faculty Of Agriculture Nagoya University
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Kitamura Masaji
Faculty Of Agriculture Nagoya University
関連論文
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : VIII. Effect of the Addition of Ammonium Sulfate on Mineralization of Nitrogen in Forest Soils
- EXPERIMENTAL STUDIES ON THE BEHAVIOR OF FINE ORGANIC PARTICLES AND WATER-SOLUBLE ORGANIC MATTER IN MINERAL SOIL HORIZONS
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : VII. Nitrogen Transformation during Incubation
- CHANGES IN SOIL ORGANIC MATTER AND NITROGEN FERTILITY DURING THE SLASH-AND-BURN AND CROPPING PHASES IN EXPERIMENTAL SHIFTING CULTIVATION
- BEHAVIOR OF PHENOLIC SUBSTANCES IN THE DECAYING PROCESS OF PLANTS : IX. Distribution of Phenolic Acids in Soils of Paddy Fields and Forests
- PREPARATION OF POWDERED SAMPLE OF FULVIC ACID AND ANALYSIS OF ITS ACID FUNCTIONAL GROUPS
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : IV. Humus Composition of Fractionated Horizons of Forest Soils
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : III. Elementary Composition of Fractionated Horizons of Forest Soils
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : VI. Mineralization of Nitrogen in Brown Forest Soils
- STUDIES ON THE HUMUS FORMS OF FOREST SOILS : V. Elementary Composition of Soil Organic Matter of Brown Forest Soils