Mineralization of soil organic nitrogen solubilized by aqua ammonia fertilizer |
| |
Authors: | S. Sen P. M. Chalk |
| |
Affiliation: | (1) Department of Agriculture and Resource Management, University of Melbourne, 3052 Parkville, Victoria, Australia |
| |
Abstract: | Organic N solubilized by NH3(aq) was extracted from 15N-labelled or unlabelled soil, concentrated and added to non-extracted soil, which was incubated under aerobic conditions at 27±1°C. Gross N mineralization, gross N immobilization, and nitrification in soils with or without addition of unlabelled soluble organic N were estimated by models based on the dilution of the NH4+or NOinf3sup-pools, which were labelled with 15N at the beginning of incubation. Mineralization of labelled organic N was measured by the appearance of label in the mineral N pool. Although gross N mineralization and gross N immobilization were increased in two soils between day 0 and day 7 following addition of unlabelled organic N solubilized by NH3(aq), there was no increase in net N mineralization. Solubilization of 15N-labelled organic N increased and the 15N enrichment of the soluble organic N decereased as the concentration of NH3(aq) added increased. A constant proportion of approximately one-quarter of the labelled organic N added at different rates to non-extracted soil was recovered in the mineral N pool after an incubation period of 14 days, and the availability ratios calculated from net N mineralization data were 1.1:1 and 2.1:1 for 111 and 186 mg added organic-N kg-1 soil, respectively, indicating that the mineralization of organic N was increased by solubilization. |
| |
Keywords: | Added nitrogen interaction Alkaline-hydrolysing fertilizer Aqua ammonia Gross N immobilization Gross N mineralization 15N Soluble organic N availability |
本文献已被 SpringerLink 等数据库收录! |
|