Use of mineralization kinetics to estimate the potentially mineralizable nitrogen of rock phosphate-enriched composts-amended soil

ABSTRACT

Predicting nitrogen (N) mineralization has been one of the greatest challenges to improving N management in agriculture. A laboratory incubation experiment was conducted to study the N mineralization of soil amended with rock phosphate (RP)-enriched composts. The RP-enriched rice straw compost amended soil mineralized highest N as compared to compost prepared from mustard stover and tree leaves. The first-order model was found to be the most suitable for N because it provided the best fit to the experimental data and for its simplicity. The model predicted that potentially mineralized N (N₀) was varied from 4.0 to 52.1 mg kg⁻¹ and the mineralization rate k varied from 0.015 to 0.066 day⁻¹. The rice straw compost amended soil had higher N₀ value than mustard stover and tree leaves compost amended soil. This study demonstrated the importance of application of rock phosphate-enriched composts in improving N supplying capacity of soil.

KEYWORDS:

• crop residues
• rock phosphate
• enriched compost
• nitrogen mineralization

Acknowledgments

The senior author thanks to the Indian Agricultural Research Institute, New Delhi for providing financial support as senior research fellowship during his research work and the Head, Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi for providing facilities for successful completion of the research works.