Characterization of non-exchaneable ammonium nitrogen in rice growing soils of Sri Lanka
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Date
1998-11-07
Authors
Nandasena, K. A.
Rizana, M.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
Ammonium nitrogen (NH/-N) trapped in interlayer spaces of clay minerals frequently termed as non-exchangeable or fixed NH; +-N form of soil nitrogen. Amount of fixed or non-exchangeable NH/-N varies from soil to soil and depends on soil type, clay content and other soil environmental conditions. Quantification of non- exchangeable form of nitrogen in our soils has not been done adequately. Therefore, the objectives of the present study are;l ). To characterize non-exchangeable NH/-N in rice growing soils and ll).To Examine release and fixation pattern of nitrogen in soil under rice cultivation in green house Condition.
Thirteen soils were collected from different agriculturally important areas of Sri Lanka. Rice plants (BG-300) were established in pots filled with soils and maintained in flooded conditions in greenhouse. Recommended fertilizers were applied except nitrogen. Soil sampling was done before and after the rice establishment. All soil samples were analyzed for non-exchangeable NH/-N using method described by Silva and Brenner (1966).
Results showed that fixed or non-exchangeable NH; +-N in studied soils varied from 12 to 28% of total nitrogen. The average amount of fixed nitrogen in our soils is around 20%. The amount of non-exchangeable NH4+-N was highly correlated with the clay contents of the soils. Therefore, it can be deduced that the amount of non- exchangeable NH;+-N in a given soils depends on the clay content. Release and fixation of non-exchangeable NH/-N during the rice growing period were also monitored. No significant difference of the amounts of non-exchangeable NH/-N extracted before and after rice cultivation was observed. This relatively unchanged pattern of non- exchangeable NH4+-N during the growing period could be attributed to the experimental conditions such as short time period of experiment and no nitrogen fertilizer practice.
Description
Keywords
Agriculture and animal sciences , Ammonium nitrogen
Citation
Proceedings & Abstracts of the Annual Research Sessions November 07, 1998,University of Peradeniya,Peradeniya, Sri Lanka,pp.02