N Mineralization as Affected by Long-Term N Fertilization and Its Relationship with Crop N Uptake
N Mineralization as Affected by Long-Term N Fertilization and Its Relationship with Crop N Uptake作者机构：Institute of Soil Science Chinese Academy of Sciences Nanjing 210008 （China）. Graduate -School of the Chinese Academy of Sciences Beijing 100039 （China）
出 版 物：《Pedosphere》 (土壤圈（英文版）)
年 卷 期：2006年第16卷第1期
页 面：125-130页
核心收录：
学科分类：09[农学] 0903[农学-农业资源与环境] 090301[农学-土壤学]
主 题：anaerobic incubation field incubation N application N mineralization N uptake
摘 要：A field experiment established in 1997 was conducted to study the effect of long-term N fertilizer application on N mineralization in a paddy soil determined using a laboratory anaerobic incubation followed with a field incubation and to measure the relationship between in situ N mineralization and crop N uptake. To estimate N mineralization in the laboratory, soil samples were collected from plots with N application at different rates for six years and were incubated. Soils treated with fertilizer N mineralized more N than unfertilized soils and mineralization increased with N application rates. Also, the fraction of total N mineralized increased with increasing N fertilizer application. These findings meant that a substantial portion of previously applied N could be recovered slowly over time in subsequent crops. The field incubation of the plot receiving no fertilizer N showed that the NH4^＋-N concentration varied greatly during the rice-growing season and seasonal changes of N mineralization were due more to accumulation of NH4^＋-N than NO3^-N. Hice N uptake increased up to a maximum of 82 kg N ha^-1 during the season. The close agreement found between in situ N mineralization and rice N uptake suggested that the measurement of in situ N mineralization could provide useful recommendations for adequate fertilizer N application.
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