Soil Nutrients and the Responses of Microbial Community Structure to Pine Bark and Vinegar Residues in Blueberry Cultivation

Abstract

The addition of suitable acidic organic materials to improve the soil for blueberry ( Vaccinium spp.) cultivation is the foundation for ensuring the sustainable development of blueberry industry in China. However, the effects of managing orchards with different inputs of organic material to improve the soil nutrients varied substantially. To unearth the best types of organic material to improve the soil fertility for blueberry cultivation and the rates to use in their application, a cultivation experiment used rooting zone restriction container and one-year-old seedlings of highbush blueberry ( Vaccinium corymbosum L. variety “Legacy”) as the test materials and pure soil as the control (CK) in this study. We compared the effects of three rates of application of pine bark and vinegar residue on the soil nutrients and microbial community structures, three concentrations of 10, 20, and 30 m 3 mu -1 of pine bark and three of 15, 30, and 45 m 3 mu -1 vinegar residue were designed to add to the soil, and they were designated PB 10 , PB 20 , and PB 30 and VR 15 , VR 30 , and VR 45 , respectively. Surface soil samples were collected for analysis after the blueberry shrubs had been planted for one year. The results showed that compared with the CK, the PB 10 treatment significantly increased the total potassium (TK), alkaline hydrolyzed nitrogen (AN) and available phosphorus (AP) contents in the soil. The PB 20 and PB 30 treatments significantly enhanced the soil organic matter (SOM), total phosphorus (TP), AN, and AP contents but significantly reduced the microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and microbial biomass phosphorus (MBP) contents. The VR 15 , VR 30 and VR 45 treatments significantly increased the contents of soil pH, total nitrogen (TN), available potassium (AK), SOM, AN, MBC and MBP. The PB 10 , PB 20 , VR 15 , VR 30 , and VR 45 treatments markedly enhanced the bacterial Shannon index. However, the VR 45 treatment markedly reduced the number of fungal species and their Chao 1, ACE, Simpson, and Shannon indices when compared with those of the CK. The soil fungal diversity was more easily regulated by soil nutrients than the bacterial diversity. A redundancy analysis showed that the dominant bacterial phyla were primarily regulated by the soil AN, while the dominant fungal phyla were primarily regulated by the SOM and MBN. In conclusion, the vinegar residue was more effective than the pine bark at improving the soil nutrients. The VR 30 treatment not only significantly improved the soil nutrients but also maintained the soil microbial diversity, which rendered it the best organic material to improve the cultivation of blueberry soil.

Keywords: Pine bark, vinegar residue, soil nutrients, microbial community structure, blueberry cultivation