AVAILABILITY TO RICE PLANTS OF NITROGEN FIXED BY Azolla
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概要
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The decomposition processes of Azolla in water and soil in relation to the availability of Azolla-nitrogen to rice plants were determined using ^<15>N as a tracer. Among the 3 species of Azolla (8 strains) used in this experiment, Azolla pinnata from Malaysia attained the highest biomass and supplied the largest amount of decaying materials to water. Azolla mexicana showed intermediate characteristics in growth and detachment of old tissues. Azolla filiculoides grew very slowly and developed symptoms of decay at early stages. The amount of ammonium excreted from Azolla into the water was negligible. When Azolla was incorporated into soil, A. pinnata underwent the most active mineralization process, followed by A. filiculoides and A. mexicana. Among the A. pinnata strains, the one from Malaysia released the largest amount of ammonium into soils. Within 6 weeks about two thirds of the nitrogen were lost from Azolla that was placed on the surface of flooded soils. Losses were about 30% from Azolla that was incorporated. Rice plants grown in a pot absorbed 50% ^<15>N-labeled Azolla-nitrogen incorporated at the time of transplanting. When Azolla was kept on the surface of water, less than 10% of its nitrogen was available to the rice plant. In the field trial, larger amounts of Azolla-nitrogen were available to rice when Azolla was incorporated than when it was placed on the soil surface. However, the availability following incorporation (12-27%) was much lower than pots. A later application (78 days after transplanting) resulted in a higher contribution of Azolla-nitrogen to grain-nitrogen than an earlier application (30 or 53 days after transplanting).
- 一般社団法人日本土壌肥料学会の論文
著者
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Watanabe Lwao
The International Rice Research Institute
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ITO Osamu
The International Rice Research Institute, Los Banos, Laguna, Phillppines
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Ito Osamu
The International Rice Research Institute
関連論文
- DIFFERENTIAL PHOSPHORUS REQUIREMENTS OF AZOLLA SPECIES AND STRAINS IN PHOSPHORUS-LIMITED CONTINUOUS CULTURE
- NITROGEN-FIXING (C_2H_2-REDUCING) ACTIVITY AND PLANT GROWTH CHARACTERS OF 16 WETLAND RICE VARIETIES
- PLANT ASSOCIATED N_2 FIXATION (C_2H_2-REDUCTION) BY FIVE RICE VARIETIES, AND RELATIONSHIP WITH PLANT GROWTH CHARACTERS AS AFFECTED BY STRAW INCORPORATION
- MICROBIAL BIOMASS NITROGEN IN ANAEROBIC SOIL AS AFFECTED BY N-IMMOBILIZATION AND N_2-FIXATION
- IMPROVEMENT OF PHOSPHATE FERTILIZER APPLICATION TO Azolla
- DYNAMICS OF AVAILABLE NITROGEN IN PADDY SOILS : I. Changes in Available N during Rice Cultivation and Origin of N
- ^N DILUTION TECHNIQUE OF ASSESSING THE CONTRIBUTION OF NITROGEN FIXATION TO RICE PLANT
- NITROGEN FIXATION ASSOCIATED WITH DEEPWATER RICE
- FATE OF NITROGEN FROM A BLUE-GREEN ALGA IN A FLOODED RICE SOIL
- IMMOBILIZATION, MINERALIZATION AND AVAILA-BILITY TO RICE PLANTS OF NITROGEN DERIVED FROM HETEROTROPHIC NITROGEN FIXATION IN FLOODED SOIL
- RESPONSE OF WETLAND RICE TO INOCULATION WITH Azospirillum lipoferum AND Pseudomonas SP
- AVAILABILITY TO RICE PLANTS OF NITROGEN FIXED BY Azolla
- RELATIONSHIP BETWEEN SOIL PHOSPHORUS AVAILABILITY AND Azolla GROWTH