| The present study was aimed to explore the effect of bio-organic fertilizers on the soil nematode population, genera and community structure in a sugarcane field. The experiment was carried out in Zhan Jiang Sugarcane Research Center from May 2012 to August 2013. The application of chemical fertilizers was used as control and three different bio-organic fertilizers were used as three individual treatments in this study, i.e. Bio-A, Bio-B and Bio-C. The population, genera and community structure of soil nematode along with the soil physicochemical properties were analyzed.The results of nematode genera identification showed that the field soil contained 21 families and 39 genera of nematodes, including 15 genera of plant-parasites,9 genera of bacterivores,8 genera of omnivores-predators and 4 genera of fungivores. The analysis of nematode community structure showed that the total number of nematode changed from 56 to 752 individuals per 100g dry soil. Plant parasite nematode was the dominant trophic group followed by bacterivores and the mean relative abundances were 78.39% and 15.64%, respectively. As compared with the control, application of the bio-organic fertilizers significantly (P<0.05) decreased the numbers of total nematode and the plant parasitic nematode at the last two sampling times, i.e. the stage of maturity and harvest time. The population of bacterivores was significantly higher in plots amended with bio-organic fertilizers than plots amended with chemical fertilizers at tillering and ripening stages. However, no significant differences were found between treatments and the control in the numbers of fungivores and omnivores-predators. The significant differences (P<0.05) were found between treatments and sampling time in H’ (Shannon-weiner diversity index), WI (Wasileska index), PPI (plant parasite nematode maturity index) and EMI (combined maturity index). The significant treatment difference (P< 0.05) was observed in λ, (dominance index) and J (evenness index). Application of bio-organic fertilizer increased H’, J, PPI and WI, While decrease in ∑MI and λ, was found in plots amended with bio-organic fertilizers.The results of nematode genera identification in sugarcane rhizosphere showed that plant parasite nematode were the dominant trophic group,which mean relative abundance were 81.45% and 83.59% at two sample stages. Number of plant parasite nematode decreased in plots amended with bio-organic fertilizers. Analysis of ecological indexes showed that H’, J increased, while λ decreased in plots amended with bio-organic fertilizers. MI, PPI and I indexes of rhizosphere soil nematodes were more sensitive to the application of fertilizers.Compared with the control, the available potassium, available phosphorus, ammonia nitrogen and nitrate nitrogen content increased, while the soil pH value reduced in plots amended with bio-organic fertilizers. Correlation analysis between nematode community and soil physicochemical properties indicated that pH, available phosphorus and available potassium had good correlation with nematode community structure. Redundancy analysis (RDA) indicated that axes 1 and axes 2 were accounted for 23.6% of the total variance, and available phosphorus, available potassium and nitrate nitrogen were the important environmental parameters that influenced the distribution of nematode.The application of bio-organic fertilizers in the sugarcane filed had a significant effect on soil nematode community structure. Compared with the control, the total number of nematodes, the numbers and abundance of plant parasitic nematode were decreased, while the numbers and abundance of bacterivores were increased in the plots amended with bio-organic fertilizers. The diversity of nematode increased, and the nematode community trended to be more stable in plots applied with bio-organic fertilizers. The analysis of nematode community and soil physicochemical properties showed that the change in nematode community could reflect soil fertility and health quality, and provide evidence for the application of bio-organic fertilizers in sugarcane field. |
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