Xing,S.H., Chen,C.R., Zhang,H., Zhou,B.Q., Nang,Z.M. and Xu,Z.H. (2011): Genotype and slope position control on the availability of soil soluble organic nitrogen in tea plantations. Biogeochemistry, 103, 245-261.

『茶プランテーションにおける土壌可溶有機窒素の有用性に対する遺伝子型と斜面のコントロール』


Abstract
 Soluble organic nitrogen (SON) plays a vital role in ecosystem N cycling processes and is controlled by a number of biotic and abiotic factors. We compared soil SON availability, microbial biomass, protease and asparaginase activities and phospholipids fatty acid (PLFA) profiles at the 0-15 and 15-30 cm layers in 10 year old tea plantations of two genotypes - Oolong tea (Camellia sinensis (L.) O. Kuntze cv. Huangjingui) (designated as ‘OT’) and Green tea (C. sinensis (L.) O. Kuntze cv. Fuyun 6) (designated as ‘GT’) - established at different slope positions. Concentrations of soil SON measured by the 2 M KCl extraction under the OT plantation were greater than under the GT plantation, while concentrations of soil SON were greater in the middle slope (MS) and lower slope (LS) positions than in the upper slope (US) position. Trends in soil microbial biomass C and N and protease and asparaginase activities between the two genotypes and across the slope positions were similar to the SON pools. The fungal-to-bacterial ratios were higher in the US position than in the MS and LS positions and higher under the GT plantation than under the OT plantation. Results from this study support that the genotype and the slope position are key factors controlling the availability of soil SON in tea plantations and also imply the importance of plant traits (e.g. litter quantity and chemistry) and soil texture in determining overall soil N availability and transformation processes and microbial community composition at the landscape level.

Keywords: Soil soluble organic nitrogen (SON); Camellia sinensis (L.) O. Kuntze; Genotype; Slope position; Phospholipid fatty acid (PLFA); Protease』

Introduction
Materials and methods
 Site description and sample collection
 Analysis of soil properties and solid state 13C NMR spectroscopy of leaf litter and roots
 Analysis of soil soluble organic N and C
 Analysis of soil microbial biomass and enzyme activities
 Analysis of phospholipid fatty acid and microbial community composition in soil
 Statistical analysis
Results
 Properties of soil and leaf litters and roots in tea plantations of different genotypes at different slope positions
 Soil SON concentrations under tea plantations of different genotypes at different slope positions
 Soil microbial biomass and enzyme activities under tea plantations of different genotypes at different slope positions
 Soil PLFA profile and microbial community composition under tea plantations of different genotypes at different slope positions
Discussion
 Effects of tea genotype on soil SON
 Effects of slope position on soil SON
Conclusions
Acknowledgements
References


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