Orchard Preparation

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 soilborne fungi and to increase soil organic matter. Disinfecting soils is another approach to improving early growth and yield on old orchard sites. 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 waterlogging and associated diseases caused by Phytophthora species. Some form of deep soil manipulation should be employed to break up fragipans and to loosen and mix horizons. For best results, the soil should be friable. After deep chiseling or subsoiling in four directions, the site is replowed to incorporate lime and fertilizer. The chemical 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 problems. 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 1.5- to 2.5-meter-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 later killed, leaving a mulch that enhances early tree growth.

0 0

Post a comment