Blueberry Field Renovation

Problem/Solution

After raising blueberries for over 30 years, it has been apparent on my farm and on other farms that I have seen that we have a problem. As per my experience and as described to me by other blueberry growers and agricultural professionals in the Ozarks, our plantings have greatly abbreviated life spans when compared to plantings in other areas of the United States. For example, Michigan and Oregon farmers can expect plantings to have life spans that surpass 50 years. A second issue concerns the poor establishment and survival of blueberry bushes that are replanted on former blueberry sites. The specific problem at Persimmon Hill Farm is that we are having declining vigor and production in our older fields. We need to refine a protocol to reclaim these older fields and through a (hopefully) expedited process, build them up to a point that will support blueberry plants at an acceptable level of production again.

My approach to this problem would be as follows:

1. Cover cropping – Will increase organic matter and , as we have seen in the past, provide increased vigor and rate of growth of the young plants. (2 cover crops Sorghum Sudan)

2. Brassica cover cropping – Large growers in Michigan have described success in replanting old fields only if chemical fumigation is used. We hope to control nematodes using this bio-fumigation method as a more sustainable practice. (2 cover crops using Caliente 199 or equiv.)

3. Soil amendments – On-farm experiments have provided promising results using pine bark and coffee grounds as soil amendments (in separate trials.) We also plan to recycle nutrients from our farm via incorporating compost generated from ground-up spent shiitake logs. (Planting will involve incorporating a mixture of pine bark, coffee grounds & composted ground-up shiitake logs.)

4.  Microb. soil inoculation – Donald Marx’s work reclaiming strip-mined land using Mycorrhizal inoculation was effective in re-vegetating the ground with which he worked. Unfortunately there is no mycorrhizae similarly beneficial to blueberry roots. However it seems that blueberry fields appear to have some of the same plant vigor challenges that could be attributed to microbiologically barren soils with which Marx worked. An additional goal here is to supplement the microbial activity in the soil within the rows through the introduction of microbes via tea brewed from worm castings in an Aerobic environment. Our hope is that the fortifying of soil within the rows with microbes will encourage the symbiotic relationship that once existed between the organisms and the blueberry plants. Control plants will remain inoculated so as to determine the efficacy of the treatment.

5. Site preparation practices – By spreading the soil from the raised ridges from our existing planting over the entire field, the impact of the cover cropping, bio-fumigation and the sun’s action on the surface of the soil will be focused on the top layer of soil. Discing between cover crops will further increase the efficacy of this practice.
The soil will later be ridged again so that plant roots will only be exposed to soil that has been exposed to the sun, cover cropping and to bio-fumigation.

6. The final cultural practice that we would like to implement is to incorporate earthworms at a high density to improve soil health and drainage. We would maintain control rows without worms to determine the efficacy of the practice.