The purpose of this project is to improve the soil conditions thus enabling us to grow blueberries under upland conditions and sustain acceptable yields. At present our 15-year-old fields are exhibiting many nutrient deficiencies in the leaves, poor cropping, and very limited root growth.
In 1998, in a one-acre field, trenches were created and then filled with composted horse manure. The pH of the soil and manure was adjusted with sulfur applications. Soil was mixed in the trench with the manure. Blueberry plants were transplanted in the spring of 1999. The plants were fertigated during the growing season with Blu-Grow liquid fertilizer. Blossoms and fruit were removed during the first growing season.
With the advice of Rick Heflebower, regional extension specialist for the University of Maryland extension system, and Dr. Gary Pavlis, Rutgers University, this project was conceived and carried out. These men provided advice on what the ideal conditions for growth are and how to modify the conditions to try to achieve these conditions. They recommended rates for the amount of manure and sulfur, etc.
The soil pH was 5.8 in 1998, 5.0 in 1999, and 5.1 in 2000. The compost was applied at 30 tons to the acre. The pH of the composted manure was 7.4. The sulfur was banded at a rate of one ton to the acre to adjust the pH. The sulfur was applied in the trench as the manure was incorporated.
This is the second growing season. The growth at this time is good. Some plants are weak and some have died, but the majority of the plants look good. There are no obvious nutrient deficiencies exhibited on the leaves. This has been common in the past. The fertigation is responsible for this.
Three varieties were planted: 214 plants of Blue Jay, 604 plants of Darrow, and 313 plants of Patriot. At the end of the first growing season the following percentage of plants had died: 1% Blue Jay, 3% Darrow, and 1% Patriot. These plants were replanted in the spring of 2000. At the end of the second growing season, the following percentage of plants had died: 2.8% Blue Jay, 2.3% Darrow, and 3.5% Patriot. The following percentage of plants is weak and may need to be replaced: 20% Blue Jay, 11.4% Darrow, and 16% Patriot. Weak plants were determined by showing less than 5 inches of growth on one-year wood and having two or less new canes. Healthy plants had three or more canes and showed more than 6 inches of new growth on one-year canes.
The Blu-Grow liquid fertilizer is 10-10-10 with trace elements. A label is attached. The first growing season, 1999, the plants were fertigated for a total nitrogen application of 20 pounds actual nitrogen for the season. After realizing that the mulch was not totally decomposed, the total nitrogen was increased to 30 pounds for the 2000-growing season to allow for adequate growth of the plants and to further decompose the mulch.
No fruit has been harvested to date. The plants are too small to support a fruit crop. I intend to remove any potential crop again in 2001 to in sure the development of strong, healthy plants.
We are hoping that the manure will sustain better root growth than we have had in the past. It appears as though our soil is rather hostile to blueberries.
Rick Heflebower, who intended to do outreach with this information, resigned his position in the late winter of 2000. His position has not been filled at this time. Therefore, no outreach has been done to date, except for conversations with individual growers as the subject comes up.
This summer I visited an experiment of different soil amendments for blueberries at the Beltsville ARSC station. From their results, it appears that drainage is the most important soil correction necessary. It had a greater positive impact on the growth of the plants than the addition of organic matter. So in the future, I might consider adding sand or another material to correct drainage.
This is a very long-term project. It took 6-8 years for problems to develop in the first planting. So it will be many years before we will know if this has corrected the problem.