FORMS OF SOIL NITROGEN AND AVAILABLE NITROGEN STATUS IN RELATION TO RICE NUTRITION IN ALLUVIAL SOILS OF THANJAVUR DISTRICT

Abstract

The role of different organic N fractions in soils on nitrogen nutrition of rice and their inter-relationship with conventional soil test methods were investigated under field condition on alluvial soils of Thanjavur District in both Kuruvai and Theladi seasons. The changes in available N status due to cropping and N ferti lisation were monitored. These studies revealed that amino-acid fraction is quanti- tatively more important among the hydrolysable nitrogen forms for rice nutrition. The fixed NH, in the alluvial soil contributes about 6 per cent of total N and also significantly correlates with yield. The content of non-hydrolysable and unidenti- fied N forms, though quantitatively important are not directly related to the immediate N availability to the rice crop. The different forms of organic N are better related with organic carbon status than with KMnO,-N, leading to scope for improvement in the modification of these methods. Since N fertilisation and its transformation have a direct bearing with the changes in available N status, it is possible: to monitor the N fertility status of soil from the initial analysis as revealed from the study.

DOI

https://doi.org/10.29321/MAJ.10.A02242

Pages

140 - 146

Creative Commons

Copyright

© The Author(s), 2025. Published by Madras Agricultural Students' Union in Madras Agricultural Journal (MAJ). This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited by the user.

Keywords