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| Changes of Water-soluble Nitrogen During Composting of Rubber Seed Cake |
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| KeyWord:rubber seed cake; sawdust; composting; water-soluble nitrogen |
| Author Name | Affiliation | | XU Zhi | College of Resources and Environment, Yunnan Agricultural University, Kunming 650102,China | | NONG Chuan-jiang | College of Resources and Environment, Yunnan Agricultural University, Kunming 650102,China | | WANG Yu-yun | College of Resources and Environment, Yunnan Agricultural University, Kunming 650102,China | | FAN Mao-pan | College of Resources and Environment, Yunnan Agricultural University, Kunming 650102,China | | TANG Li | College of Resources and Environment, Yunnan Agricultural University, Kunming 650102,China |
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| Hits: 1894 |
| Download times: 1984 |
| Abstract: |
| Rubber seed cake, a by-product after oil extraction, contains nutrients and may be used as fertilizer after composting. Here we studied the changes of nitrogen in rubber seed cake during composting with sawdust at 0 and 65% sawdust（W/W）. Water-soluble total nitrogen, water-soluble organic nitrogen, water-soluble inorganic nitrogen, water-soluble NH+4-N and water-soluble NO-3-N and temperature were measured during the compositing process. The influence of filtrate from composted cake on seed germination was also tested. The composting process of rubber seed cake was slow, and was not completed at the end of experimental period. Addition of sawdust could expedite the composting process of rubber seed cake. Contents of water-soluble total nitrogen, water-soluble organic nitrogen, and water-soluble inorganic nitrogen were decreased after increasing at the begining during composting process. The percentage of water-soluble organic nitrogen in the water soluble total nitrogen reduced gradually, while water soluble inorganic nitrogen proportion in the water soluble total nitrogen increased gradually. At the end of composting, NO-3-N was the dominate water soluble inorganic nitrogen. For the treatment with rubber seed cake only, the water-soluble total nitrogen, water-soluble organic nitrogen, water-soluble inorganic nitrogen was 6 819.5 mg·kg-1, 4 983.0 mg·kg-1 and 1 836.8 mg·kg-1，respectively. The water-soluble inorganic nitrogen and water-soluble organic nitrogen accounted for 29.9% and 70.1 % of total nitrogen; water-soluble NH+4-N was 87.1% of the water soluble inorganic nitrogen. For the treatment with rubber seed cake + sawdust, however, the water-soluble total nitrogen, water-soluble organic nitrogen, water-soluble inorganic nitrogen was 3 136.0 mg·kg-1, 1 863.4 mg·kg-1 and 1 272.7 mg·kg-1，respectively. The water-soluble inorganic nitrogen and water-soluble organic nitrogen were respectively 40.5% and 59.5% of total nitrogen, while water-soluble NO-3-N comprised 81.1% of the water soluble inorganic nitrogen. |
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