Pedosphere 7(4): 297--302, 1997
ISSN 1002-0160/CN 32-1315/P
©1997 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of long-term straw incorporation on soil microbial biomass and C and N dynamics |
| SHEN Ren-Fang1, P. C. BROOKES2 and D. S. POWLSON2 |
1 Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Naming 210008 (China);
2 Soil Science Deportment, Rothamsted Experimental Station, Harpenden, Hens AL5 2JQ (UK) |
| ABSTRACT |
| A study was performed on the long-term effect of straw incorporation on soil microbial biomass C contents, C and N dynamics in both Rothamsted and Woburn soils. The results showed that for both soils, the microbial biomass C contents were significantly different among all the treatments, and followed the sequence in treatments of straw chopped and incorporated into 10 cm (CI10) > straw burnt and incorporated into 10 cm (BI10) > straw chopped and incorporated into 20 cm (CI20) > straw burnt and incorporated into 20 cm (BI20). Laboratory incubation of soils showed that the cumulative CO2 evolution was closely related to the soil microbial biomass C content. Carbon dioxide evolution rates (CO2-C, μg (g•d)-1) decreased rapidly in the first two weeks' incubation, then decreased more slowly. The initial K2SO4-extractable NH4-N and NO3-N contents were low and similar in all the treatments, and all increased gradually with the incubation time. However, net N immobilization was observed in chopped treatments for Rothamsted soils during the first 4 weeks. Nevertheless, more N mineralization occurred in Treatment CI10 than any other treatment at the end of incubation for both soils. The Woburn soils could more easily suffer from the leaching of nitrate because the soils were more permeable and more N was mineralized during the incubation compared to the Rothamsted soils. |
| Key Words: C and N dynamics, microbial biomass C, soil incubation |
| Citation: Shen, R. F., Brookes, P. C. and Powlson, D. S. 1997. Effect of long-term straw incorporation on soil microbial biomass and C and N dynamics. Pedosphere. 7(4): 297-302. |
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