Effects of cyanamide fertilizer on microbial community structure of continuous cropping soil
With the increasing demand for vegetables, continuous vegetable cropping was more popular and common in China, which will result in seriously continuous cropping obstacle in fields. Imbalance of soil microbial community structure, decline in bio-diversity, reduction in quantity of beneficial microor...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Zhejiang University Press
2013-05-01
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| Series: | 浙江大学学报. 农业与生命科学版 |
| Subjects: | |
| Online Access: | https://www.academax.com/doi/10.3785/j.issn.1008-9209.2012.08.232 |
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| Summary: | With the increasing demand for vegetables, continuous vegetable cropping was more popular and common in China, which will result in seriously continuous cropping obstacle in fields. Imbalance of soil microbial community structure, decline in bio-diversity, reduction in quantity of beneficial microorganism and accumulation of pathogenic microorganism were major factors of continuous cropping obstacles. Soil microorganism plays an important role in maintaining balance, health and high quality of soil ecosystem. Changing of microbial community structure directly influenced soil function, thereby produced negative effect on plant growth. Using artificial regulation measures such as adjusting microbial community structure and increasing bio-diversity, was an effective method to overcome continuous cropping obstacles. Calcium cyanamide and dicyandiamide (DCD) were cyanamide fertilizers, which had significant inhibition effect on harmful organisms, especially on pathogenic fungi in soil. However, effects of cyanamide fertilizers on microbial community structure and bio-diversity of continuous cropping soil were unclear.The aim of this research was to study the effects of calcium cyanamide and dicyandiamide application on microbial community structure in continuous vegetable cropping soil. Results of the study might reveal the soil micro-ecological mechanism of calcium cyanamide and dicyandiamide to control eggplant verticillium wilt, and provide theoretical foundation and technical guidance for cyanamide fertilizers application in agricultural production.The experimental soil was silt paddy soil and was collected from farmland in Quzhou, Zhejiang Province. In the farmland, the planting years of eggplant were more than four years, and verticillium wilt of eggplant was severe and out of control in the last year. Six treatments were designed in experiments: 1) control, 2) dicyandiamide, 3) calcium cyanamide (lime nitrogen), 4) straw, 5) dicyandiamide + straw, 6) calcium cyanamide+straw. Soils of different treatments were incubated at 25 ℃. Through conventional artificial culture method, quantities of bacteria, fungi and actinomycetes were recorded. Community structure and bio-diversity of bacteria and fungi were analyzed by PCR-DGGE.Results showed that, calcium cyanamide application effectively increased the number of bacteria, decreased the amount of fungi, improved the ratio of bacteria to fungi and actinomycetes to fungi in the continuous cropping soil. But dicyandiamide showed no distinct influence on the number of bacteria. Dicyandiamide and dicyandiamide plus rice straw application increased the ratio of bacteria to fungi with the high value of 2.48 and 9.96 times in the 30 days. Calcium cyanamide and calcium cyanamide plus rice straw application obviously increased the ratio of bacteria to fungi with the high value 8.42 and 58.39 times in the 30 days. So, application with calcium cyanamide in the continuous cropping soil could change the microbial community structure, restore the imbalance microbial community structure into a healthy status for vegetable growth by changing the dominant microbial community structure from fungi to bacteria, and then controled the soil-borne disease in the continuous vegetables cropping soil. The results of PCR-DGGE also indicated that, cyanamide fertilizer application altered the community structure of bacteria and fungi, induced the appearance of new species and biotic population, and inhibited some other population. In the continuous vegetables cropping soil, the diversity index and richness of bacteria were decreased with the calcium cyanamide application in the early stage (8 days after application), but the bacteria community diversity and richness were increased in the later stage (20 days after application). Dicyandiamide application obviously increased the diversity index and richness of bacteria than calcium cyanamide application. The calcium cyanamide and dicyandiamide application could improve the diversity index and richness of bacteria and fungi. On the whole, the effect on microbial community structure was higher in the calcium cyanamide application treatment than in the dicyandiamide application treatment. Furthermore, cyanamide fertilizer application with rice straw addition could obviously improve the microbial community structure in continuous vegetable cropping soil.In conclusion, calcium cyanamide, especially combined with straw application, can significantly change microbial community structure, improve imbalanced eco-system, recover healthy ecological environment in continuous cropping soil. It might be one of the principal mechanisms for the cyanamide fertilizers showing good effects on controlling soil-borne fungal diseases. |
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| ISSN: | 1008-9209 2097-5155 |