Authors: Respectively, Extension Pecan Specialist, Department of Extension Plant Sciences; Professor of Agricultural Economics, Department of Agricultural Economics and Agricultural Business; and Doña Ana County Extension Agriculture Agent, all of New Mexico State University, Las Cruces, NM.
Extraordinary advances have been made in the field of chemistry in the past century, and the high yields and high quality produced by modern farms can be attributed in large part to the use of synthetic pesticides and fertilizers. However, borne out of concern that these synthetic chemicals might cause human disease and environmental damage, the organic movement has developed in support of agriculture that uses safe, environmentally friendly and natural (i.e., non-synthetic) means of enriching soils and controlling pests.
It took several decades for organic agriculture to gain popular acceptance, but by the 1990s organic agriculture had clearly entered mainstream America. According to the Food Marketing Institute, about half of U.S. shoppers now buy organic foods and almost 3/4 of retail food stores in the U.S., including some of the largest national grocery store chains, carry organic foods. Furthermore, there are 2.2 million acres of organic cropland and pasture in the U.S. today. The organic tree nut industry makes up a tiny but very rapidly growing sector of U.S. organic agriculture. In 1997 there were 4,908 acres of organic tree nut acres nationwide; by 2005 the U.S. organic tree nut industry had more than tripled in size, reaching 15,986 acres. Most of this growth was in California, but in 2005 there were 111 acres of certified organic pecan orchards in New Mexico.
Until recently, there were no nationally agreed upon standards as to which methods or chemicals were permissible within organic agriculture and, as a result, it was often difficult for consumers of “organic” products to know exactly how the products they were buying differed from “conventional” products. But with an ever-increasing presence of organic agriculture nationwide, the U.S. Department of Agriculture (USDA) put into action in 2002 the National Organic Program (NOP), a formalized organic certification program. Today, all agricultural products bearing the “organic” label must have been produced and handled in accordance with the National Organic Standards.
What does “organic” mean?
“Organic food is produced by farmers who emphasize the use of renewable resources and the conservation of soil and water to enhance environmental quality for future generations. Organic food is produced without using most conventional pesticides; fertilizers made with synthetic ingredients or sewage sludge; bioengineering; or ionizing radiation.”
—National Organic Program, “Organic Food Standards and Labels: The Facts”
Mineral Nutrition in Organic New Mexico Pecan Orchards
To grow and set fruit normally, pecan trees require adequate levels of 14 mineral nutrients: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, zinc, iron, boron, manganese, molybdenum, copper, chlorine and nickel. Deficiency in any one of these nutrients can potentially limit pecan yield—but only a few of these minerals are commonly deficient in New Mexico pecan trees. As the basis of your orchard mineral nutrition program, the nutritional status of your trees should be assessed annually, using tissue analysis of July-sampled leaves.1
Nitrogen (N) deficiency often limits pecan yields in New Mexico; this is particularly true in organic orchards. Conventional pecan growers in New Mexico typically apply 150–300 lbs of actual N per acre annually. Synthetic fertilizers allow conventional growers to precisely control the rate and timing of N application in their orchards, because these fertilizers have a consistent known content of N and the N in these fertilizers is immediately available to the tree for uptake. Without all the advantages of synthetic N fertilizers, it is critical for organic pecan growers to monitor the N status of their trees much more closely than conventional growers do, in order to avoid deficiencies and maintain productivity.
Many organic producers use manure or compost as the primary sources of N in their operations. Since nuts are harvested onto the ground, the use of raw (non-composted) animal manures in pecan orchards carries with it the risk that nuts will be contaminated with bacteria that cause food-borne illnesses in humans. To minimize this risk as much as possible, and to preserve consumer confidence in the safety of organic products, the NOP rules require that non-composted animal manures be incorporated at least 120 days before harvest (NOP § 205.203). Composted manures do not pose the same threat and may be applied at any time, but must be composted following the rules set out in the Organic Standards 205.203.
Manure and compost should always be tested by a qualified analytical laboratory before they are applied in an orchard, because of variability in quality. First, the laboratory analyses should tell you the N concentration of the manure (it can vary from 1–3%) so that you can calculate how much N you are actually applying in your orchard. Second, the analyses should tell you how much inorganic N (immediately available N) vs. organic N (slowly available N) is present in the manure or compost.2 Third, the analyses should tell you the Carbon:Nitrogen (C:N) ratio of the manure or compost. As its C:N ratio increases, manure or compost increasingly ties up soil N and may actually induce temporary N deficiencies in pecan orchards. NOP guidelines specify that compost must have an initial C:N ratio between 25:1 and 40:1 (NOP § 205.203). Finally, the analyses should tell you the salt concentration of the manure or compost, so that damaging salts (e.g., sodium and chloride) do not build up in your soils. Avoid manures with high salt content, particularly if your orchard has a heavier-textured soil.3
Additional non-synthetic fertilizer sources of N commercially available for organic growers are available, but note that if you plan to use a compounded nitrogen fertilizer product you must determine its suitability for use in organic production. The word “organic” on a fertilizer label does not necessarily mean that this fertilizer is allowed for use in organic production. If you are unsure, check with your organic certifier. Allowable nitrogen sources include blood meal, feather meal, fish meal, cottonseed meal and soybean meal. Cottonseed or soybean meal must not be derived from genetically modified plants.
Chilean nitrate (sodium nitrate) is a mined source of highly soluble nitrogen which provides many of the benefits of conventional fertilizers but is allowable in organic agriculture, with certain restrictions. Chilean nitrate is allowable only if it accounts for no more than 20% of your orchard’s total annual nitrogen requirement (NOP § 205.602); the reasons for its use must be addressed in the organic system plan. Also, be aware that use of Chilean nitrate may significantly contribute to salinity and sodicity problems in heavier and poorly drained soils and, since its use is prohibited in the organic standards of some other countries, it may not be appropriate for organic pecans intended for export.
New Mexico’s soils are generally calcareous type soils, having an alkaline pH (>7). Some micronutrients, such as zinc, might be present in such soils in adequate quantities, but are largely unavailable for uptake by pecan trees because of the alkaline pH. Generally, micronutrient deficiencies are only effectively prevented or reversed through foliar fertilizer applications. Although sulfates and oxides of zinc and other micronutrients are considered “synthetic,” these chemicals are permitted by the NOP for use in organic pecan orchards if a deficiency can be demonstrated (NOP § 205.601).
Can a legume cover crop meet the nitrogen needs of my pecan orchard?
Legumes inoculated with the appropriate strain of bacteria can capture (“fix”) atmospheric nitrogen. Some legume species, including clovers, vetches and alfalfa, can fix enough nitrogen to meet much of your pecan orchard’s nitrogen needs when planted between the tree rows. In addition to nitrogen fixation, planting a legume cover crop in your orchard also carries with it other benefits:
But this option for nitrogen fertilization also presents some limitations in orchards:
Pest Management in Organic New Mexico Pecan Orchards
One of the goals in an organic pecan orchard operation is to rely first and foremost on non-chemical management practices for maintaining insects, diseases and weeds at acceptable levels. Organic growers should use chemical controls (i.e., nonsynthetic chemicals or synthetic chemicals from the NOP-approved list) only if management practices alone do not provide adequate control and if proper documentation has been provided (NOP § 205.206). Due to its arid climate and geographical isolation from other pecan growing areas, New Mexico has few arthropod pests or diseases that affect pecans, which greatly simplifies pest control for organic orchardists.
Aphids are one of the most important insect pests affecting New Mexico pecans—and one of the most difficult to control in organic operations. The yellow pecan aphid species complex, which includes blackmargined aphids (Monellia caryella) and yellow pecan aphids (Monelliopsis pecanis), can be a problem throughout most of the growing season. Yellow pecan aphids exert their negative influence in two ways: 1) by “stealing” sugars and nutrients necessary for tree growth and fruiting, and 2) by blocking sunlight for photosynthesis when leaves become coated with sticky honeydew (aphid excrement), which promotes sooty mold growth. Black pecan aphids (Melanocallis caryaefoliae) are a threat mainly in the late summer and fall, especially in shady, crowded orchards. When black aphids feed, they inject a toxin, killing surrounding leaf tissues and sometimes entire leaves. Black aphid infestations reduce trees’ active photosynthetic leaf area at a critical time in the season—when the kernels are growing and winter carbohydrate storage reserves in the trunk and roots are being filled.
Some pecan cultivars are resistant to aphids, so the first line of defense against aphids in organic orchards can lie within the genetics of the trees themselves. For new organic plantings in New Mexico, ‘Pawnee’ is a good choice for a main cultivar because it is high yielding, well-adapted to New Mexico’s climate, and quite resistant to yellow pecan aphid infestation. On the other hand, ‘Burkett’ is reportedly much more susceptible to black pecan aphid infestations than other cultivars.
Ladybeetles, lacewings, mirids and a number of other predatory insects have a voracious appetite for aphids and can also play an important role in suppressing aphid populations. Predatory insects may be naturally abundant in your orchard. There are commercial suppliers of these predatory insects; if natural populations of these insects are low in your orchard, you can try to boost populations through periodic releases within your orchard. Vegetation on the orchard floor provides cover for predatory insects and may help to encourage these insects to actually take up permanent residence in your orchard. If you want to encourage orchard floor vegetation in mature orchards, maintaining good canopy sunlight penetration (less than 60% shade on orchard floor at noon) by means of tree thinning or pruning will help; this will also lessen your orchard’s susceptibility to black aphid infestation.
The pecan nut casebearer (PNC) is a moth which, in its larval form, feeds on pecan nuts. In New Mexico there are three or four PNC generations per year; the first generation, appearing in mid to late May, is the most destructive to pecan yields and should be the main focus of PNC control programs. Parasitoid wasps found in New Mexico can help keep PNC populations in check.4 But there are pesticides effective against PNC available labeled for organic pecan orchards (see text box) and, especially in low yield seasons, it will likely be necessary to sometimes apply one of these chemicals to keep PNC damage sufficiently low. To control PNC, it is critical that sprays targeted against the caterpillars be carefully timed to the 1- to 2-day period between egg hatch and larval entry into the developing nutlets. As the appearance of the first PNC generation may vary between years by as much as two weeks, you should use pheromone traps and physical orchard scouting to determine when to spray. Temperature-based PNC emergence models are available for some parts of New Mexico and can also help to predict spray dates.
Weeds are both a blessing and a curse for New Mexico organic pecan orchards. Weed growth below the orchard canopy benefits the soils in various ways, and ground covers—including weeds—provide cover for beneficial insects in the orchard. However, weeds often interfere with normal orchard operations and compete with pecan trees for precious nutrients and water. Especially in young orchards, a weed-free area of at least a few feet should be maintained around the base of each tree.
Assuming care is taken not to damage tree trunks, methods such as cultivation (e.g., discing or hand hoeing) and flaming with a propane torch are simple and effective non-chemical management practices organic pecan growers can use to maintain weed-free areas around pecan trees, or even an entirely weed-free orchard floor. However, some of these non-chemical approaches to weed management are highly labor intensive and are practical only for very small orchard operations. There is one approved herbicide currently allowed for use in organic operations and registered for pecan orchards, a contact herbicide whose main active ingredient is clove leaf oil (trade name, Matran®).
If strips of weeds are permitted to grow between tree rows, those weeds should be mowed (or grazed) regularly so that they do not interfere with harvest and other orchard operations. The irrigation system you choose can also greatly affect your weed management program: compared with flood irrigation, micro-irrigation (e.g., drip or microsprinkler irrigation) that wets only part of the orchard floor significantly reduces orchard weed pressure.
What insecticides may I use in my organic pecan orchard?
There are only a few insecticides available to organic pecan growers. Before applying a chemical, be sure to compare the pesticide formulation to an up-to-date list of approved pesticides, since approved active ingredients often appear in formulations not approved for organic use. The Organic Materials Review Institute (OMRI) maintains such a list, but the final decision about whether a pesticide is approved rests with your certifier. Check with your certifier before you spray, and list pesticides you may want to use in your annual certification application. The following is a list of some insecticides currently approved for use in organic pecan orchards:
Remember: even natural chemicals can be dangerous! In order to effectively and safely use pesticides, it is always important to follow directions on the label.
Harvesting, Processing, and Storing Organic Pecans
National organic program standards “address the methods, practices, and substances used in producing and handling crops, livestock, and processed agricultural products” (NOP Organic Production and Handling Fact Sheet), but give little specific guidance to organic pecan producers regarding how harvesting and processing equipment is to be used. Cleaning harvesting equipment before use in an organically-certified orchard is necessary to prevent contamination of organic nuts with conventional nuts or prohibited substances. But harvesting equipment need not be exclusively dedicated to organic production.
As with harvesting equipment, an organic producer does not have to find a processor who handles organic products exclusively, but to maintain organic certification, a processor does need to ensure that equipment is clean and that organic and conventional products are neither mixed nor come into direct contact with each other. All handlers (first and subsequent processors) must implement measures necessary to clean processing equipment, prevent commingling of organic and conventional products, and protect organic products from contact with prohibited substances.
Most shellers segregate organic pecans into a separate area of the cold storage unit to avoid conflict, reduce record-keeping issues, and eliminate risk of accidental commingling. Check with your broker, sheller and subsequent processors to make sure that adequate precautions will be taken to segregate pecans in separate areas of the storage facility and that adequate bulk labeling measures will be taken.
What organic labeling options exist?
There are three primary options for organic labeling. Depending upon your choice of production, harvesting, and marketing opportunities, you must decide which one fits you best.
In the three-year period between commitment to organic certification and actual certification, pecans may be labeled transitional. In some markets growers may receive a price premium for transitional products relative to other conventional products.
Marketing Organic Pecans5
Organic pecans, like virtually all organic commodities, generally have a per-pound cost of production disadvantage relative to their conventional counterparts. Yields are often lower as a result of higher losses due to nutrient deficiencies and pests. Although chemical costs may be lower as well, reduced costs may not offset reduced yields. To maintain or exceed conventional profitability, an organic producer should receive price premiums or make use of special marketing opportunities.
Organic certification certainly opens new avenues for sales without closing any others. Market opportunities are worth a great deal, a factor that is not always measured in sales price. To continue competitively, however, price advantages are necessary. So far, organic buyers are showing willingness to pay a premium at retail (and consequently at wholesale) for organic produce.
Plan on either using an established organic pecan marketer or spending a great amount of time on the telephone developing personalized local (as well as regional and national) contacts. First-time organic pecan producers are almost always better off selling pecans at established farmers’ markets or by contracting the services of an established organic pecan broker—there is a steep learning curve in getting direct retail or wholesale organic or conventional product sales going.
When working with local, individual organic food markets, expect most sales to be in case sizes, but just a few cases at a time. Sales to chains (such as Whole Foods, Wild Oats, or Wal-Mart) may involve greater volume, but are very difficult to arrange, since those chains usually already have contracted with a supplier.
Organic pecans represent a small but growing segment of the pecan market. This suggests that room remains for additional market expansion. However, expansion will not come without a significant amount of individual work and effort. Overall, the outlook for all organic foods in the United States, Canada, Western Europe, and Japan is positive, both for market penetration volumes and for prices. Markets for organic and for conventional foods are distinct but not separate. Organic premiums cannot greatly exceed conventional prices; some consumers may switch back to conventional products if prices in the two market segments diverge too much.
What marketing outlets can I use for my organic pecans?
Sources and Further Online Reading
Agricultural Marketing Service, USDA (www.ams.usda.gov).
ATTRA—National Sustainable Agriculture Information Service (www.attra.org).
Economic Research Service, USDA (www.ers.usda.gov).
Food Marketing Institute (www.fmi.org).
New Mexico Organic Commodity Commission (nmocc.state.nm.us).
Organic Materials Review Institute (www.omri.org).
Organic Trade Association (www.ota.com).
Sustainable Agriculture Research and Education (www.sare.org).
1For more information about leaf sampling and leaf analysis read NMSU Extension publications Guide H-619, Sampling Pecan Leaves for Analysis, and Guide H-617, Interpreting Leaf Analysis and Deficiency Symptoms of Pecans.
2In this case, the term organic has nothing to do with NOP regulations per se, but refers to the presence of nitrogen in carbon-containing molecules.
3Read more about managing soil salinity in NMSU Extension publication Guide H-644, Leaching Requirements of Pecan and Fruit Trees, at www.aces.nmsu.edu/pubs/_h/h-644.pdf
4See Guide H-653, Biological control of pecan nut casebearer and aphids in New Mexico pecans, available online at www.aces.nmsu.edu/pubs/_h/H-653.pdf
5To read more about ways to market your organic pecans, see Guide Z-307, Marketing Channels for Pecans, available online at www.aces.nmsu.edu/pubs/_z/Z-307.pdf
The purpose of this publication was to answer your questions about organic pecan production and marketing in New Mexico. Perhaps it has stimulated your interest in learning more about organic pecans, specifically, or about pecan production in general. You can find out much more about the particular cultural requirements for pecan trees by consulting your county Extension office or the NMSU College of Agriculture and Home Economics website (www.cahe.nmsu.edu; click on “publications and videos”) for viewable/printable pecan publications in addition to those cited here.
References to chemical tradenames contained in this publication do not constitute endorsements of those products by the authors or by New Mexico State University.
The authors are grateful to Joanie Quinn (NMOCC), Brett Bakker (NMOCC), Joran Viers (NMSU), Joe Ellington (NMSU) and Sally Harper (Del Valle Pecans) for their assistance in reviewing and editing this manuscript.
To find more resources for your business, home, or family, visit the College of Agricultural, Consumer and Environmental Sciences on the World Wide Web at aces.nmsu.edu.
Contents of publications may be freely reproduced for educational purposes. All other rights reserved. For permission to use publications for other purposes, contact firstname.lastname@example.org or the authors listed on the publication.
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Printed and electronically distributed November 2007, Las Cruces, NM.