Three studies were conducted to determine the effects of organic management on plant health and soil biology in blueberry production fields in Michigan. The first study evaluated the effects of mulches, cover crops, and organic fertilizer on microbial populations in soil. Significant treatment effects were found, which indicates that microbial populations are responsive to cultural practices and soil inputs. This information may be used to enhance populations of naturally occurring beneficial microbes in soil. Cultivable soil fungi, bacteria, and beneficial microorganisms were positively correlated with soil pH and appeared to be suppressed at the low pH range of blueberry soils. In a second study, we assessed mycorrhizal colonization and soil biology in organic and conventional production fields. Sharp contrasts were observed in N:P enzyme ratios, labile C and N pool sizes, and mycorrhizal colonization, and organic fields had higher values for all of these parameters. Lastly, we evaluated organic options for control of fruit rot and cane diseases in three separate on-farm trials. Promising organic disease control methods were identified, but none matched the control provided by standard synthetic fungicide treatments. These studies will provide a background for further research into improved organic blueberry production methods in Michigan.
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