Spatial distribution and biomass of root nodules i

Authors: Hiroyuki Tobita Shigeaki F Hasegawa Xingjun Tian Satoshi Nanami Hiroshi Takeda

Publish Date: 2009/12/02

Volume: 50, Issue: 1-2, Pages: 77-86

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Abstract

To estimate nodule biomass of Alnus hirsuta var sibirica an N2fixing tree species we examined the distribution pattern and size structure of nodules in a 17 to 18 year old stand naturally regenerated after disturbance by road construction in Japan Nodules were harvested within 1 m from the outer edge of stems of plants with different sizes on four occasions from June to October The diameter of the subtending root at the base of each nodule and nodule dry weight were measured in 20 cm increments outwards from the base of each stem Horizontal distribution of nodules around each tree varied greatly among tree diameters at 13 m dbh within the evenaged stand In particular smaller individuals had a concentrated distribution of nodules close to the stem Nodule abundance occurred further from the stems with increasing tree size Nodule biomass within 1 m from the outer edge of individual stems increased with tree size nodule biomass = 0442 dbh201 R 2 = 0747 P  005 By using the relationship nodule biomasses were estimated to be 841 kg ha−1 These results suggest that it is necessary to take into account tree size and patterns of tree distribution in nodule biomass estimates

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