Cooperative Extension, University of California FRUIT & NUT NOTES Yolo County January 2002 IN THIS ISSUE: South Sacramento Valley Almond Meeting Tree Planting Tips Plant New Trees High Frost UC Fruit & Nut Research and Information Center SOUTH SACRAMENTO VALLEY ALMOND MEETING Yolo, Solano, Colusa, Yuba-Sutter Counties February 15, 2002 9:00am to 12:15pm Norton Hall, 70 Cottonwood Street, Woodland, CA 8:30am 9:00am 9:30am 10:05am 10:40am 10:55am 11:30am 12:05pm Coffee and Donuts Almond Production Strategies to Ensure Food Safety by Tom Krugman, Senior Director, Policy and Administration, Almond Board of CA in Modesto Almond Variety Development at UC Davis by Tom Gradziel, Dept. of Pomology at UC Davis Micro vs. Drip Irrigation and Pruning Young Trees by John Edstrom, UC Farm Advisor in Colusa County Break Some Possible Cost Cutting Ideas by Wilbur Reil, UC Farm Advisor in Yolo/Solano Counties Bloom and Foliar Diseases by Beth Teviotdale, UC Cooperative Extension Plant Pathologist at UC Kearney Agricultural Center in Parlier, CA Wrap-up: General Almond Questions That Have Not Been Answered by John Edstrom and Wilbur Reil *****We have applied for PCA and Private Applicator credits.**** University of California and U.S. Department of Agriculture cooperating
TREE PLANTING TIPS Preplant Prepare planting site early enough to allow proper settling before planting. Do all leveling, ripping, subsoiling or backhoeing the summer before so winter rains can settle before planting. Make sure the soil surface at the planting site is as high or higher than surrounding soil. All plant vegetation should be removed or killed preceding the actual tree planting operation. Excessive vegetation that is buried can deplete nitrogen, cause planting problems and create toxic gas that will kill roots. Layout and stake field before starting to plant. Planting Plant when soil moisture is ideal. Don t plant in excessively wet soils and don t auger holes in wet soils. In wet soils, hand dug holes are better but are not good. Even cutting sides does not remove all the problems created in planting in wet holes. If the soil is too wet, trees will do better placed in cold storage. Wait until soil moisture is ideal before planting. Remember, new roots need oxygen to heal and callus. Extremely wet soil does not have much oxygen, therefore poor growth can be expected from trees planted in overly wet soil. Don t allow roots to dry when transporting, storing or planting. Roots should be covered and keep moist until planted. If trees are healed in before planting, select a site free of pest or disease problems ideally within the same field being planted. Dig or auger holes the day of planting. Do not glaze the sides or bottom of hole. At planting, cut any excessively long roots and any crossed or broken roots from the nursery tree, otherwise roots do not have to be pruned. Don t allow the roots to dry before planting. Roots should be treated for crown gall by spraying the roots with Agrobacterium radiobacter (Galltrol or Norbac). If trees are healed in and then planted they should be treated before healing in and then again at planting. Plant trees so that the crown will remain high. Usually the top root should be planted at ground level. Don t be afraid to mound up dirt to cover roots. Some holes will settle 3 inches, so allow for future settling when planting. Don t plant trees with the idea of pulling them up later. Roots can be damaged when trees are pulled up and usually it will never get done, so plant the tree right the first time. After settling, the new tree should never be deeper than it was planted in the nursery. Dirt should never cover the graft union. On heavy soil, make mounds 6 to 8 inches higher than surrounding ground and approximately 3 feet in diameter. Plant trees on top of the mound. The extra work required to irrigate the trees the first year will be more than compensated by better tree survival and growth. Hand place roots in hole so that roots are straight and pointed downward. Make sure the roots are not curved around hole or the ends of the root are not curved upward. 2
Back-fill dirt into hole placing friable loose, moist soil around roots. Press dirt firmly around roots making sure that no air pockets occur around the crown. When planting trees in the winter before tree growth starts, as long as soil is moist don t water after planting. If planting trees out of cold storage in late March, April or later, trees may need to be watered at planting. If trees require watering at planting, don t overwater. Two or three gallons is maximum. Don t saturate the hole or allow the soil to remain excessively wet. Cut almond and prune trees at about 36 inch height. On June bud trees, leave trunk with no side branches; on yearling trees, leave three stubs approximately 1 inch long (2 buds) in desired location. On walnuts cut off grafted trees to 4 buds above graft. Ungrafted trees should be cut off at approximately 12 to 16 inches. Paint the tree to reduce potential damage from sunburn or borers. White interior latex paint either straight or diluted 1:1 with water is satisfactory. Paint the tree to below ground level then apply the last shovels of dirt around the trunk. Tree protectors will protect against rabbits and may offer some protection from errant herbicide sprays. Post Planting Whether trees are planted in ideal moisture or are watered lightly at planting, don t rewater until after trees are growing well (about 6 inches new growth) and then only when the moisture has become somewhat depleted around the root area. The first few irrigations are the most critical to good tree growth. Irrigate too soon and the tree roots suffer and die from lack of oxygen and Phytophthora root rot; too late and tree growth ceases. Digging down around roots to check moisture is an excellent practice that cannot be overemphasized. Stake walnut trees with an 8 to 10 foot 2 inch treated stake or pole with the top 6 to 8 feet above ground on the windward side. Place stake 8 to 12 inches from trunk. When tying tree to stake tie loosely with l inch tying tape or tree rope. Don t tie tight, let the tree sway. Control weed growth around the tree after planting. If you use herbicides, make sure it is registered for use on young nonbearing trees, doesn t damage the tree, and is used correctly. Intercropping is not advisable but if it is financially required, remember that the trees are the main crop. Don t mismanage the trees or allow them to suffer. Don t select intercrops that will cause pest buildup (Verticillium, nematodes, etc.) or need to be dried out during the summer for harvest (hay, grain). Provide adequate irrigations to keep trees growing throughout the spring and summer. Never place nitrogen fertilizer in the planting hole at planting time. 3
Fertilize tree only after it is growing well and only use very small quantities (not over 1 ounce N per tree). Don t place the fertilizer next to the trunk but sprinkle it 18 away from the tree. Water the fertilizer adequately to distribute throughout the root zone. On sprinkler irrigated trees apply at least 2 inches of water following a fertilizer application. Frequent light applications of nitrogen is better than a single large amount. PLANT NEW TREES HIGH I keep stressing the need to plant trees correctly in orchards and have used several different methods to describe what I mean. Plant the top root above the ground surface. Then cover it with extra dirt. Dig the hole deep enough for most of the roots, then mound up dirt to cover the rest of the roots. Plant the tree so that the soil line where it was planted in the nursery is 4 to 6 inches above ground level. Allow for 3 to 6 inch settling of the planting hole! All of these statements have one basic concept. Make sure the tree crown is high-definitely higher than in the nursery row even after settling. While not all tree loss is caused by improper planting, the biggest single factor for your trees dying is trees settling too deep after planting and then water ponding around the crown during wet periods. Most of our soils in Yolo and Solano County are heavy with a high clay content. The soil has excellent water holding capacity. It also has slow water percolation; therefore, the soil remains saturated longer than on well drained sandy soils. The mound around the tree trunk allows excess surface moisture to drain away from the tree, thus reducing the length of time the crown is exposed to saturated conditions. This saturated condition can occur at planting time, when the trees are irrigated, or when a high rainfall winter and spring occurs. Some orchards survive for several years before a wet spring kills those trees that settled too deep. Plant the tree right the first time. Make sure the ground is in proper shape and the soil has good moisture. Then make sure the crown is high after planting. The only person that might be happy if you plant the tree too deep will be your nursery person. You will need to buy another tree when the first one dies! Do the job right the first time and avoid costly replanting and loss of production. Now, after making a strong case for planting the tree high, there is at least one exception. On Marianna 2624 plum rootstock, planting trees high causes them to rootsucker more than when planted deeper. Therefore, plant this rootstock the same depth as planted in the nursery. Plum rootstocks also can tolerate wetter conditions than most other rootstocks. Planting them at the same depth they grew in the nursery should not affect survival of trees grown on Marianna 2624 plum as long as the bud union remains above ground level. 4
FROST Although we normally don t want to think about problems such as frost that occur during the spring, there are a few cultural practices that can help minimize damage. Sometimes one or two degrees difference in temperature can mean whether a crop is lost or saved. Tall vegetation or weed growth is the coldest condition possible but very loosely disked soil is not too much warmer. The following chart shows approximate temperature differences that can be expected under various orchard floor management practices. Ground Preparation Temperature Change* ========================================================== Bare, Firm, Moist Ground Warmest Shredded Covercrop, Moist Ground ½ F cooler Low Growing Covercrop, Moist Ground 1 to 3 F colder Dry, Firm Ground 2 F colder Freshly Disked, Fluffy Ground 2 to 3 F colder High Covercrop 2 to 4 F colder High Covercrop Restricted Air 6 to 8 F colder Drainage *All conditions are compared to bare, firm, moist ground. Strip weed control down the tree row will provide warm conditions in proportion to the area without vegetation, i.e. if 25 percent of the total is bare and 75 percent has a high cover crop, the orchard will be 1-1/2 to 3 F colder than bare, firm, moist ground. UC FRUIT AND NUT RESEARCH AND INFORMATION CENTER UC Fruit and Nut Research and Information Center is on line at http://fruitsandnuts.ucdavis.edu. It contains information on many subjects concerning fruit and nut crops. If you have trouble accessing it, you can get help through e-mail: fruitsandnuts@ucdavis.edu or by calling 530-754-9708. A large part of the Center s work is disseminating information on the World Wide Web. This web site is easy to use and compiles statewide fruit and nut information in one place to provide the user an efficient way to stay informed 24 hours a day. The Center s web page continues to grow with timely and relevant information for growers, industry, researchers and consumers. Here are some of the highlights from the web site: Individual Crop Pages Links To Related Boards, Commissions UC Publications Available and Organizations UC Extension and County Information Weather Conditions and Issues California Tree Crop Statistics Course and Event Agendas and Weekly News and Information Highlights Consumers and Growers Monthly Contact Information To UC Tasty Picks Researchers Links To Related Departments, Centers Winter Chilling Information and Programs 5
Submitted by, Wilbur Reil To simplify information, when trade names have been used, no endorsement of products named is intended, nor criticism implied of products which are not mentioned. --------------------------------------------------------------------------------------------------------------------- The University of California prohibits discrimination against or harassment of any person employed by or seeking employment by or seeking employment with the University on the basis of race, color, national origin, religion, sex, physical or mental disability, medical condition (cancer-related or genetic characteristics), ancestry, martial status, age, sexual orientation, citizenship, or status as a covered veteran (special disabled campaign badge has been authorized). University Policy is intended to be consistent with the provisions of applicable State and Federal laws. Inquiries regarding the University s nondiscrimination policies may be directed to the Affirmative Action/Staff Personnel Services Director, University of California, Agriculture and Natural Resources, 1111 Franklin, 6 th Floor, Oakland, CA 94607-5200. Telephone (530) 987-0096. University of California and U.S. Department of Agriculture cooperating. Cooperative Extension Presort Standard U.S. Department of Agriculture Postage and Fees Paid University of California USDA 70 Cottonwood Street Woodland, CA 95695 Woodland, CA 95695 Permit No. G-00268 January 8, 2002 Inside: South Sacramento Valley Almond Meeting February 15, 2002 6
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