Seasonal variation of fixed ammonium content of paddy soils in Hunan Province and its bioavailability
Liao, J.; Li, F.; Zhang, Y.; Feng, Y.; Huang, Y.
Ying Yong Sheng Tai Xue Bao 14(10): 1665-1668
2003
ISSN/ISBN: 1001-9332 PMID: 14986361 Document Number: 559273
Three paddy soils with higher content of fixed ammonium in Hunan Province were used as test soils in pot experiment to study the seasonal variation of their fixed ammonium content and its bioavailability during rice growth period. The results showed that the fixed ammonium content in the paddy soils changed constantly during rice growth. Applying N fertilizer and organic manure increased the fixed ammonium content, which was decreased through the N uptake by rice plants. The recently fixed ammonium was almost fully available to rice, while the native fixed ammonium was partly available. The release of fixed ammonium during rice growth was newly alluvial sandy soil > purple clayey soil > alluvial sandy soil, and was greater a early growth stage than at later growth stage.