Relationship between rhizosphere soil properties and disease severity in highbush blueberry (Vaccinium corymbosum)

In order to understand the effects of soil physical and chemical properties on the disease status and death of highbush blueberry (Vaccinium corymbosum L.) plants, the microbial diversity, enzyme activity, soil nutrient availability, pH, soil organic matter and element content of various parts of the poorly-performing and healthy plants were studied. The rhizosphere soil pH(water) was higher in healthy than poor highbush blueberry plants. The content of available potassium was higher in the rhizosphere, and in contrast, that of exchangeable calcium and magnesium lower, in the rhizosphere than non-rhizosphere soil of both poor and healthy plants. The microbial diversity and the relative abundance were lower in the rhizosphere than non-rhizosphere soil, and were lowest in the rhizosphere soil of the poor plants. The catalase and acid phosphatase activities were higher in the rhizosphere than non-rhizosphere soil, but there was no difference in invertase activity. Redundancy analysis indicated that the relative abundance of Mizugakiibacter, Rhodanobacter, Gamma_proteobacterium_OR-113, Castellaniella, Acidobacterium, Bryobact, and Ottowia was positively correlated with soil acid phosphatase and invertase activities, available potassium and iron, and organic matter content, and was negatively correlated with pH, catalase activity and exchangeable calcium and magnesium. The content of Fe was lower in the dead compared with healthy roots. Therefore, it was known from the above experimental results that the poor growth of blueberry plants may be related to the acid phosphatase activity, the microbial diversity and relative abundance of rhizosphere soil.