Issue link: http://read.dmtmag.com/i/61297
Soils & Nutrients Get spacing and rootstock right C Growers making the best choices make the most money. by Richard Lehnert hoosing the right apple varieties—ones that enjoy good con- sumer demand and sell for a good price—is the most important step an apple grower can take toward profitability, says Dr. Terence Robinson, Cornell University pomologist. But once a grower makes his choices, the real hard work begins. The orchard needs to be planted, and the choice of rootstocks and spacings are vitally important. "If you do everything right, you can still make money if you plant the right variety in an 8 by 16 spacing and 340 trees per acre," Robinson told apple growers at the Mid-Atlantic Fruit and Vegetable Convention in Hershey, Pennsylvania, in February. But, he added, economic analyses show the highest profitability occurs when growers plant about 1,000 trees per acre. It is up to the grower to find the combination of rootstock and soil that will fill the space rapidly but not be too vigorous at that spacing. In making decisions about rootstocks, growers must look at econom- ics (precocity and productivity), liveability, rootstock vigor, scion vigor, Terence Robinson, in orchard with microphone, talking about tall spindle orchard design, is a familiar sight to growers in New York and in other states in the Midwest and Northeast. built to meet Storage Solutions . . . Delivered to your site Shelving 30 Fire Protection Contaiment Pan New and Used Refurbished Buildings Available Ventilation 8 x 509 88or4-0555 26 APRIL 15, 2012 GOOD FRUIT GROWER 8 10 x 30 Contact us at 30 www.rentmestorage.com climate, soil type and fertility, irrigation/fertigation, replant disease, spacing, and training system, he said. Robinson is one of the developers of the tall spindle system, in which trees are trained to grow 10 to 12 feet tall in a narrow profile that contains no permanent scaffold limbs. Using that system, a thousand trees planted three to four feet apart in rows 10 to 12 feet apart will fill an acre. He suggests the following: —Use a 3-foot spacing for weak and medium vigor varieties. —Use a 4-foot spacing for vigorous varieties. From strongest to weakest, he ranks scion vigor in this order: Mutsu, Northern Spy, Jonagold, McIntosh, Cameo, Fuji, Gala, Empire, Idared, Greening, Macoun, SweeTango, Jazz, Spur Delicious, NY1, and Honeycrisp. Geneva rootstocks Cornell has had a rootstock breeding program for some time, and its Geneva rootstocks are just now reach- ing commercial availability. Robinson is convinced they will be superior because they were selected to be disease resistant, precocious, and productive. But there are not enough of them now. In making rootstock decisions to get the right rootstock to fit the spacing, he suggests: —Use vigorous clones of M.9 (Nic29 or RN29) for medium vigor cultivars or when planting on replant soil. —Use weak clones of M.9 (T337 or Flueren56) for vigorous varieties or on virgin soil. —Use M.26, interstems, or M.7 for very weak varieties. —Use irrigation and/or fertigation to improve lack of vigor. —Use limb bending and limb renewal pruning on tall spindle system trees to keep trees slender. Rootstocks that live In choosing a rootstock, the primary consideration is, will the tree live, he said. "Fireblight is devastating in New York and in Michigan and some other areas," he said. "Some method to control fireblight is critical." Fireblight infects blossoms and can move, in 60 days, down into the rootstock. "If M.9 and www.goodfruit.com ORDER TODAY Photo by richard lehnert