Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil
Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, l...
| Main Authors: | , |
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| Format: | Conference or Workshop Item |
| Language: | English |
| Published: |
Australian Academy of Science
1981
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| Online Access: | http://psasir.upm.edu.my/id/eprint/33883/ http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf |
| _version_ | 1848847621954732032 |
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| author | Chulan, Azizah Waid, John S. |
| author_facet | Chulan, Azizah Waid, John S. |
| author_sort | Chulan, Azizah |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, laterals or radicles; treatments Nod, Lat and Rad respectively. Soil samples were incubated aerobically at 30 C for 16 weeks. The radicles, laterals and nodules respectively contained 1.65, 3.46 and 6.91 mg N per sample and their C to N ratios were 16.5, 7.0 and 4.2.
The root fragments disappeared rapidly and less than 40% and 10% of their initial dry weight remained after 1 and 16 weeks respectively; nodules decomposed more rapidly than laterals and laterals more quickly than radicles. At 16 weeks the total N contents of the controls had not changed but Rad, Lat and Nod soils respectively showed gains over the controls from week 1 onwards and by week 16, these amounted to 8.2, 17.1 and 31.8%. Concentrations of mineral N increased in all soils from week 4 onwards and by week 16, the amounts of mineral N that had accumulated in Nod, Lat and Rad were 1.62, 1.16 and 1.14 times greater than in the controls (201 ~ N g-l oven-dry soil).
Under the conditions of this experiment, the legume root and nodule tissues discomposed rapidly and all of the legume root N (except an unaccounted for 5.6% of the nodule N) was transferred to the soil without any apparent net loss or gain of volatile N.
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| first_indexed | 2025-11-15T09:21:31Z |
| format | Conference or Workshop Item |
| id | upm-33883 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-15T09:21:31Z |
| publishDate | 1981 |
| publisher | Australian Academy of Science |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-338832015-04-14T02:49:39Z http://psasir.upm.edu.my/id/eprint/33883/ Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil Chulan, Azizah Waid, John S. Samples (20 g) of an air-dry, sieved (<2mm) silty loam with or without (controls) the incorporation of 200 mg root portions of Centrosema pubescens, were moistened to 50% moisture holding capacity at 0.33 bar (33 kPa). The root portions were healthy, freshly harvested, clean samples of nodules, laterals or radicles; treatments Nod, Lat and Rad respectively. Soil samples were incubated aerobically at 30 C for 16 weeks. The radicles, laterals and nodules respectively contained 1.65, 3.46 and 6.91 mg N per sample and their C to N ratios were 16.5, 7.0 and 4.2. The root fragments disappeared rapidly and less than 40% and 10% of their initial dry weight remained after 1 and 16 weeks respectively; nodules decomposed more rapidly than laterals and laterals more quickly than radicles. At 16 weeks the total N contents of the controls had not changed but Rad, Lat and Nod soils respectively showed gains over the controls from week 1 onwards and by week 16, these amounted to 8.2, 17.1 and 31.8%. Concentrations of mineral N increased in all soils from week 4 onwards and by week 16, the amounts of mineral N that had accumulated in Nod, Lat and Rad were 1.62, 1.16 and 1.14 times greater than in the controls (201 ~ N g-l oven-dry soil). Under the conditions of this experiment, the legume root and nodule tissues discomposed rapidly and all of the legume root N (except an unaccounted for 5.6% of the nodule N) was transferred to the soil without any apparent net loss or gain of volatile N. Australian Academy of Science 1981 Conference or Workshop Item PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf Chulan, Azizah and Waid, John S. (1981) Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil. In: Nitrogen Cycling in South-East Asian Wet Monsoonal Ecosystems, 5-10 Nov. 1979, Chiang Mai University, Thailand. (pp. 150-153). |
| spellingShingle | Chulan, Azizah Waid, John S. Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title | Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title_full | Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title_fullStr | Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title_full_unstemmed | Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title_short | Loss of nitrogen from decomposing nodules and roots of the tropical legume Centrosema pubescens to soil |
| title_sort | loss of nitrogen from decomposing nodules and roots of the tropical legume centrosema pubescens to soil |
| url | http://psasir.upm.edu.my/id/eprint/33883/ http://psasir.upm.edu.my/id/eprint/33883/1/33883%20loss%20of%20nitrogen.pdf |