Planning and Preparing a Site for a New Orchard Begins 2 to 3 Years Ahead of Planting
Posted: March 26, 2015
Fruit growing is a high-risk venture, and Penn State Extension offers budgets and spreadsheet programs to assist you in business planning. Optimal site preparation and planting involve thinking in terms of managing tree roots for increased orchard performance. Physical, chemical, and biological properties of the soil must all be considered. Soil structure is a major concern on a new site. A replant site requires two to three years of crop rotations to replenish organic matter and avoid tree mortality or stunted growth.
Cold-air drainage and soil quality have significant effects on the profitability of an orchard. An ideal site is on the upper side of a gradual (4 to 8 percent) slope, on rolling or elevated land. Low lying areas, where cold air can accumulate during a calm, clear night, are prone to spring frost damage. Hilltops or ridges may expose trees to excessive winds or to arctic air masses.
A preferred orchard soil is a deep (at least 3 ft), well-drained and aerated loam. Detailed soil appraisals should be conducted several years in advance of planting. A grower begins by locating a soil map and by digging test holes to examine the soil profile. Soil maps provide useful information on soil texture, parent material, native fertility, erosion levels, and water-holding capacity. Test holes reveal impervious layers and water-related problems. If checked several times during a rainy period, test holes will yield valuable information on the soil water table.
Topsoil and subsoil samples also are collected at this time for analysis of pH, nutrient imbalances, and organic matter content. Additional site considerations include access to water for irrigation and spraying, the presence of weeds that serve as reservoirs for plant viruses, and the potential for hail or other weather-related disasters.
Orchard Design and Tree Quality
Give considerable thought to orchard design and tree quality. Important considerations are canopy light interception and distribution to flowers and fruit. Branched trees on dwarfing rootstocks will produce early crops.
Trees grown in north-south oriented rows have better light conditions than those grown in east-west rows. Decreasing the distance between rows and increasing tree height also increases light interception. With most tree forms, optimum tree height is half the row spacing plus 3 ft. Maximizing production per acre by planting trees in high densities requires careful assessment of the vigor potential of a site. It is helpful to evaluate tree size in a previous orchard or in an adjacent block. Other factors that affect decisions on tree arrangement include topography, equipment size, and worker access.
To obtain the scion/rootstock combinations best suited to an orchard plan, order trees 2 to 3 years ahead of planting. Ordering virus-tested trees with healthy root systems ensures a good start for a sustainable production system. Well-feathered trees are desirable for early cropping, intensive systems. Windbreak trees, if needed, and pollinizer trees also should be ordered early. Studies indicate that the best trees for windbreaks are alders (Alnus), willows (Salix), or other deciduous species that leaf out early in the spring and hold leaves past harvest time. Fruit tree bloom periods vary from one region to another, and it is wise to get local advice on pollinizers.
The one chance a grower has to optimize the soil environment is prior to planting. Before disturbing the surface vegetation, spot treatments can be made to control perennial and other problem weeds. On replant sites, a cover-cropping system can be established and maintained for several years to suppress weeds, nematodes, and soil-borne fungi and to increase soil organic matter. Soil drainage problems should be corrected with subsurface drainage systems or surface modifications such as ridging. Stone fruit and certain dwarf apple rootstocks are especially sensitive to water logging and associated diseases caused by Phytophthora species. The fertility status of the soil is ameliorated to the depth of the root zone, since lime and phosphorus are not very mobile and potassium moves slowly.
After the soil is thoroughly prepared, an orchard groundcover is established. Turf grasses often are the most desirable groundcovers, especially species that suppress voles, broadleaf weeds, and soil-borne diseases. Grasses also conserve nutrients, increase organic matter, protect groundwater quality, and improve water infiltration. To prevent erosion, the groundcover should be established shortly after the site is cultivated and leveled. Grass seed can be sown in the row middles, leaving 4 ft-wide bare strips where the trees are planted, or seed can be sown over the entire field. In the latter system, the sod is established at least one season before planting and the tree strip killed prior to planting, leaving a mulch that enhances early tree growth.
Several studies show that time of planting greatly affects initial tree growth. Early planted trees have increased shoot numbers and length, and fewer trees become spur-bound or stunted. Orchards should be planted as early in the spring as the ground can be worked or in late fall in regions where sudden drops in temperature are unlikely. Trees may be planted by a variety of methods provided close root-soil contact is secured and the trees are not planted too deeply. To prevent scion rooting, the bud union of dwarf trees should be 3 inches above the soil line. Higher bud union placement is generally avoided due to the potential for burr knots or winter injury on some rootstocks. Soon after planting, the trees should be watered and, if needed, a support system established.
The goal of advance planning and site preparation is to ensure early and regular crops of high value fruit for the 15 to 30 year life of an orchard. Preplant use of sustainable management practices guarantees that a site will support the current orchard and generations to come.
For more information see Penn State's Tree Fruit website.
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