Issue link: http://read.dmtmag.com/i/61297
Orchard floor management A Sod alleyways should be maintained free of blooming plants. by Richard Lehnert well-managed orchard—whether pome fruit or stone fruit—is made up of the right trees planted in weed-free strips separated by lawn-quality sod alleyways that are free of all flowering plants. That's the look advocated by Rutgers University weed specialist Dr. Bradley Majek. He contends that when labels on insecticides say, "don't apply during bloom," it doesn't mean just tree bloom, it means bloom in the orchard of any kind. "That labeling is meant to protect pollinators, no mat- ter what is attracting them to the orchard," he said. "That could mean dandelions in the spring, white clover in the summer, or goldenrod and white asters later in the season." That means the "sod alley" should really be sod and not just a collection of whatever happens to grow there. Majek advocates that growers plant tall fescue or hard fescue when establishing an orchard. "Both types of fescue are tolerant to disease, drought, low pH, and low fertility," he said. "They compete effec- tively with weeds, do not spread or creep into the tree row by rhizome or stolen growth, and are semi-dormant during the hot dry summer months." Tall fescue is more vigorous and is more easily established, he said, but requires more frequent mowing. "The addition of clover or other legumes is not recommended for orchard sods," he said. While they do fix some nitrogen, they are alternate hosts for pests, especially tomato ringspot virus, and they flower, luring bees to the orchards and exposing them to insecticides. This is the look growers should strive for in their orchards—a solid sod cover free of blooming plants. This look is appropriate for both pome and stone fruits. Before planting the trees, plant 25 to 75 pounds of fes- cue seed per acre, in late summer, into fertilized soil, he suggests. Use a good seeder that puts seed into the soil, and pack it firmly. Plant the fescue only where the perma- nent alleys will be. Where the tree rows will be, plant perennial ryegrass, which grows fast. In late fall or early the next spring, use the herbicide glyphosate to kill strips of sod where the trees will be planted, and plant directly into the killed sod. Killing the sod in late fall or early winter will allow the sod roots to break down, so using a tree planter will be easier in the spring. The dead sod will provide organic matter, help suppress weeds, and prevent soil erosion until the trees are growing well. The width of the strip should be from 33 VAPOR GARD® FOR CHERRIES t o (with early application) INCREASED SH b s Using VAPOR GARD on cherries offers growers these benefits: INCREASED SIZE & YIELD REDUCED SPLITTING (from untimely rain) INCREASED SHELF LIFE (greener stems) LIFE MILLER CHEMICAL & FERTILIZER CORP. 800-233-2040 SEE LABEL FOR ADDITIONAL INFORMATION AND ALWAYS READ AND FOLLOW LABEL DIRECTIONS 28 APRIL 15, 2012 GOOD FRUIT GROWER to 40 percent of the alley width, or narrower if a more vigorous rootstock is used. The sod can be used to reduce vigor somewhat, he said. It will take 15 to 22 months to establish a dense sod competitive with weeds, he said. During that time, he suggests using Prowl H2O each spring to control annual grasses and 2,4-D to control broadleaf weeds. The herbi- cide 2,4-D works well on dandelions but is weaker on white clover. Stinger, which is better on clover, is labeled for use on stone fruits. Starane Ultra will suppress white clover in pome fruits, he said. Tillage not recommended While few orchardists maintain clean-tilled orchards today, clean tillage was once widely used, especially by peach growers. The pros and cons of tillage or no tillage were once debated. Weeds compete for water, nutrients, sunlight, and space, he said, and are a host for pest insects and diseases and provide cover for rodents. They can compete for pollination, and they reduce harvest efficiency. Clean tillage eliminates these problems, but at the expense of soil quality. Tillage destroys organic matter, which leads to soil compaction and poor water infiltra- tion, and opens the ground to soil erosion. Tillage also damages tree roots, making them vulnerable to diseases and less able to take up nutrients and water. Sod, he said, adds roots to the soil that improve soil structure, water uptake, and formation of healthy soil aggregates. Sod row middles are minimally competitive with trees for water and nutrients, he said. They provide a good working surface for machinery. No voles One additional benefit comes from mowing. Majek recommends growers use a side-discharge mower, rather than a flail mower, and throw the grass clippings into the weed-free strip. This addition of mulch replaces organic matter that can not grow there because of the herbicides, but does not make enough residue to be attractive to rodents like voles. Were it not for the problem of voles, he said, growers might want to choose mulch as a better choice for weed control than herbicides. In experiments he conducted, fruit trees made their best growth and best yield under mulches, either of fabric or of leaves or similar organic materials like wood chips or hay. The mulches reduce soil temperatures and increase both moisture and fertility. But the problem of rodents, even under fabric, has not yet been solved, he said. Tall fescue sod requires an annual fertilizer program that provides 40 to 80 pounds of nitrogen annually. Some of this will be transferred to the tree rooting areas as the sod is mowed and the clippings blown into the row. Majek presented this information as the Ernie Christ Memorial Lecture during the Mid-Atlantic Fruit and Vegetable Convention in Hershey, Pennsylvania. • www.goodfruit.com PPhoto courtesy of Peter shearer, osu N t G u e neric i S u t e!