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Changes in microbial biomass after continuous application of azolla and rice straw in soil

Soil science and plant nutrition Volume 43 Issue 4 Page 811-818
published_at 1997-12
2007020034.pdf
[fulltext] 2.75 MB
Title
Changes in microbial biomass after continuous application of azolla and rice straw in soil
Creators Azmal Abul Kalam Mohammad
Creators Marumoto Takuya
Creators Shindo Haruo
Creators Nishiyama Masaya
Creator Keywords
azolla C and N mineralization continuous application microbial biomass rice straw tropical soil fertility
A model experiment was conducted under tropical conditions with a view to evaluating the changes in microbial biomass and nutrient dynamics in upland soil through the continuous application of azolla and rice straw (2 g C kg^<-1> soil per each application). Flush decomposition of C was observed immediately after each application and the rate of mineralization did not change appreciably during this period. After flush decomposition, the rate of C mineralization from azolla was higher than that from rice straw until 9 to 13 weeks after each application and thereafter the mineralization rate was similar. The amount of inorganic N released from azolla increased following each application, whereas inorganic N in rice straw plot was immediately immobilized and the rate of immobilization increased until the 3rd application and did not increase further after the 4th application. The amounts of biomass C and N increased immediately after residue incorporation, reached the maximum level one week after each application and declined thereafter. Maximum biomass formation increased until the 2nd application and then the level remained constant. Maximum biomass N formation was higher in azolla than in rice straw after the 1st application, but after repeated applications, the difference became less pronounced. Continuous increase in biomass in a certain week after each application was observed, probably because of the cumulative effects of the previous applications. The increase suggests that continuous application of organic materials may enable to improve the amount of soil microbial biomass.
Subjects
農学 ( Other)
Languages eng
Resource Type journal article
Publishers 日本土壌肥料学会
Date Issued 1997-12
File Version Version of Record
Access Rights open access
Relations
[ISSN]0038-0768
[NCID]AA00844314
[isVersionOf] [NAID]http://ci.nii.ac.jp/naid/110001718184/
[isVersionOf] [URI]http://www.blackwellpublishing.com/journal.asp?ref=0038-0768&site=1
Schools 農学部