Journal article

Publication year: 1984

Pages: 291-294

Journal: Soil Science Society of America Journal

Volume number: 48

Issue number: 2

ISSN: 0361-5995

eISSN: 1435-0661

DOI Link: https://doi.org/10.2136/sssaj1984.03615995004800020012x

Publisher: Wiley

Abstract: 
The release of nonexchangeable (fixed) NH4+ was studied for 3 representative rice soils of the Philippines. Soil samples from these soils were treated with 15NH4+ in the laboratory so that they contained appreciable amounts of nonexchangeable NH4+ in 15N form. Special soil holders were filled with the labeled soil and incubated in the wetland rice soils from July-Oct. at a depth of 0.2 m. During this period of incubation, highly significant amounts of labeled nonexchangeable NH4+ were released from all 3 soils. For the Maligaya silty clay loam and Guadalupe clay, both containing vermiculite, the total release of nonexchangeable NH4+ was higher than the release of labeled nonexchangeable NH4+ showing that non-labeled NH4+ was released as well. 15N analysis of the rice plants showed that the nonexchangeable labeled NH4+ was subsequently available to the crop. Assuming a soil bulk density of 1 and a rooting depth of 0.2 m release of nonexchangeable NH4+ from the Maligaya silty clay loam ranged from 80 to 100 kg N ha-1, while for the Guadalupe clay and Santa Rita clay the net release of nonexchangeable NH4+ amounted to about 20-40 kg N ha-1, respectively. Nonexchangeable NH4+ may play a major role in N nutrition of rice crops grown in wetland rice soils rich in vermiculite.

Harvard Citation style: KEERTHISINGHE, G., MENGEL, K. and DEDATTA, S. (1984) THE RELEASE OF NONEXCHANGEABLE AMMONIUM (N-15-LABELLED) IN WETLAND RICE SOILS, Soil Science Society of America Journal, 48(2), pp. 291-294. https://doi.org/10.2136/sssaj1984.03615995004800020012x

APA Citation style: KEERTHISINGHE, G., MENGEL, K., & DEDATTA, S. (1984). THE RELEASE OF NONEXCHANGEABLE AMMONIUM (N-15-LABELLED) IN WETLAND RICE SOILS. Soil Science Society of America Journal. 48(2), 291-294. https://doi.org/10.2136/sssaj1984.03615995004800020012x