Organic nitrogen components in soils from southeast China

： Objective： To investigate the amounts of extractable organic nitrogen （EON）, and the relationships be- tween EON and total extractable nitrogen （TEN）, especially the amino acids （AAs） adsorbed by soils, and a series of other hydrolyzed soil nitrogen indices in typical land use soil types from sout...

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Published inJournal of Zhejiang University. B. Science Vol. 14; no. 4; pp. 259 - 269
Main Authors Chen, Xian-you, Wu, Liang-huan, Cao, Xiao-chuang, Zhu, Yuan-hong
Format Journal Article
LanguageEnglish
Published Heidelberg SP Zhejiang University Press 01.04.2013
Springer Nature B.V
Zhejiang University Press
Subjects
acids
Amino
Amino Acids - analysis
Biomedical and Life Sciences
Biomedicine
Biotechnology
Bulk
China
Extractable
nitrogen
Nitrogen - analysis
organic
Organic Chemicals - analysis
Rhizome - chemistry
Rhizosphere
soil
Soil - analysis
Soil - chemistry
S151.9
Rhizosphere
Amino acids
Extractable organic nitrogen
Bulk soil
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Summary:： Objective： To investigate the amounts of extractable organic nitrogen （EON）, and the relationships be- tween EON and total extractable nitrogen （TEN）, especially the amino acids （AAs） adsorbed by soils, and a series of other hydrolyzed soil nitrogen indices in typical land use soil types from southeast China. Under traditional agricultural planting conditions, the functions of EON, especially AAs in the rhizosphere and in bulk soil zones were also inves- tigated. Methods： Pot experiments were conducted using plants of pakchoi （Brassica chinensis L.） and rice （Oryza sativa L.）. In the rhizosphere and bulk soil zone studies, organic nitrogen components were extracted with either distilled water, 0.5 mol/L K2SO4 or acid hydrolysis. Results： K2SO4-EON constituted more than 30% of TEN pools. K2SO4-extractable AAs accounted for 25% of EON pools and nearly 10% of TEN pools in rhizosphere soils. Overall, both K2SO4-EON and extractable AAs contents had positive correlations with TEN pools. Conclusions： EON repre- sented a major component of TEN pools in garden and paddy soils under traditional planting conditions. Although only a small proportion of the EON was present in the form of water-extractable and K2SO4-extractable AAs, the release of AAs from soil exchangeable sites might be an important source of organic nitrogen （N） for plant growth. Our findings suggest that the content of most organic forms of N was significantly greater in rhizosphere than in bulk soil zone samples. However, it was also apparent that the TEN pool content was lower in rhizosphere than in bulk soil samples without added N.
Bibliography:Extractable organic nitrogen, Amino acids, Rhizosphere, Bulk soil
33-1356/Q
Xian-you CHEN Liang-huan WU, Xiao-chuang CAO, Yuan-hong ZHUMinistry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 3 10058, China3Department of Crop and Soil Sciences, the Pennsylvania State University, University Park, Pennsylvania PA 16802, USA E-mail： finm@ziu.edu.cn Zhejiang University and Springer-Verlag Berlin Heidelberg 2013
Objective： To investigate the amounts of extractable organic nitrogen （EON）, and the relationships be- tween EON and total extractable nitrogen （TEN）, especially the amino acids （AAs） adsorbed by soils, and a series of other hydrolyzed soil nitrogen indices in typical land use soil types from southeast China. Under traditional agricultural planting conditions, the functions of EON, especially AAs in the rhizosphere and in bulk soil zones were also inves- tigated. Methods： Pot experiments were conducted using plants of pakchoi （Brassica chinensis L.） and rice （Oryza sativa L.）. In the rhizosphere and bulk soil zone studies, organic nitrogen components were extracted with either distilled water, 0.5 mol/L K2SO4 or acid hydrolysis. Results： K2SO4-EON constituted more than 30% of TEN pools. K2SO4-extractable AAs accounted for 25% of EON pools and nearly 10% of TEN pools in rhizosphere soils. Overall, both K2SO4-EON and extractable AAs contents had positive correlations with TEN pools. Conclusions： EON repre- sented a major component of TEN pools in garden and paddy soils under traditional planting conditions. Although only a small proportion of the EON was present in the form of water-extractable and K2SO4-extractable AAs, the release of AAs from soil exchangeable sites might be an important source of organic nitrogen （N） for plant growth. Our findings suggest that the content of most organic forms of N was significantly greater in rhizosphere than in bulk soil zone samples. However, it was also apparent that the TEN pool content was lower in rhizosphere than in bulk soil samples without added N.
Corresponding Author
ISSN:1673-1581
1862-1783
DOI:10.1631/jzus.B1200104