Pedosphere 26(2): 257--264, 2016
ISSN 1002-0160/CN 32-1315/P
©2016 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Microbial biomass dynamics in a tropical agroecosystem: Influence of herbicide and soil amendments |
A. SINGH, M. K. SINGH and N. GHOSHAL |
| Centre of Advanced Study in Botany, Department of Botany, Banaras Hindu University, Varanasi 221005 (India) |
| ABSTRACT |
| The influences of herbicide alone and in combination with the soil amendments with contrasting resource qualities on dynamics of soil microbial biomass C (MBC), N (MBN), and P (MBP) were studied through two annual cycles in rice-wheat-summer fallow crop sequence in a tropical dryland agroecosystem. The experiment included application of herbicide (butachlor) alone or in combination with various soil amendments having equivalent amount of N in the forms of chemical fertilizer, wheat straw, Sesbania aculeata, and farm yard manure (FYM). Soil microbial biomass showed distinct temporal variations in both crop cycles, decreased from vegetative to grain-forming stage, and then increased to maximum at crop maturity stage. Soil MBC was the highest in herbicide + Sesbania aculeata treatment followed by herbicide + FYM, herbicide + wheat straw, herbicide + chemical fertilizer, and herbicide alone treatments in decreasing order during the rice-growing period. During wheat-growing period and summer fallow, soil MBC attained maximum for herbicide + wheat straw treatment whereas herbicide + FYM, herbicide + Sesbania, and herbicide + chemical fertilizer treatments showed similar levels. The overall trend of soil MBN was similar to those of soil MBC and MBP except that soil MBN was higher in herbicide + chemical fertilizer treatment over the herbicide + wheat straw treatment during rice-growing period. In spite of the addition of equivalent amount of N through exogenous soil amendments in combination with the herbicide, soil microbial biomass responded differentially to the treatments. The resource quality of the amendments had more pronounced impact on the dynamics of soil microbial biomass, which may have implications for long-term sustainability of rainfed agroecosystems in dry tropics. |
| Key Words: chemical fertilizer, farmyard manure, organic amendment, Sesbania aculeata, wheat straw |
| Citation: Singh, A., Singh, M. K. and Ghoshal, N. 2016. Microbial biomass dynamics in a tropical agroecosystem: Influence of herbicide and soil amendments. Pedosphere. 26(2): 257-264. |
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