Koenig, Richard T.

Lindstrom, Thor

English

DigitalCommons@USU

ACKNOWLEDGMENTSPublication of this series of UtahState University Extensionfertilizer guides is made possibleby a grant from the UtahDepartment of Agriculture andFood through the CooperativeFertilizer Checkoff Research andEducation Program.SOIL, WATER AND PLANTTISSUE TESTING IN UTAHORCHARDSRichard T. Koenig, Extension Soil SpecialistThor Lindstrom, Fruit Tree ResearchTechnicianDecember 2001 AG-FG-02INTRODUCTIONFruit trees require the appropriate soiland irrigation water conditions, as well asproper fertilization, in order to maximize fruityield and quality. Diagnosing soil, water andplant fertility conditions involves testing eachcomponent at the appropriate time duringorchard development. Soil testing is importantbefore establishing an orchard to evaluateinitial site conditions and take any correctiveaction before trees are planted, and at regularintervals to determine if soil conditions arechanging. Irrigation water testing is importantto evaluate the quality and limitations of awater source prior to its use on trees, and periodically to determine if water quality is changing.Finally, plant tissue (“leaf”) testing is the most reliable and timely indicator of fruit tree nutrientstatus in orchards and should be done on an annual basis or more frequently if problems arise.SOIL TESTING IN UTAHORCHARDSSoil testing is oneimportant tool used to evaluatethe suitability of a new site foran orchard. Many soils in Utahhave high levels of soluble salts(“salinity”) and/or high pH.Either condition can reduce treevigor and fruit production and,at extremely high levels, canThe Orchard Fertility SeriesThe orchard fertility series consists ofseveral bulletins from Utah StateUniversity Cooperative Extensiondescribing the latest information on soiland fertilizer management for fruit trees. The guides are available in printed formfrom your local county Extension office, oron the Internet at http://extension.usu.eduunder Agriculture Publications.cause complete orchard failure. Texture is also an important characteristic of orchard soils. Fruittrees generally perform well in soils with adequate drainage, such as sandy or loam-texturedsoils. Soil nutrient levels also influence fruit tree production. Deficiencies in soil nutrient levelscan be corrected much more easily by diagnosing the problem through soil sampling andincorporating the appropriate nutrients before planting trees.Soil properties can vary across an orchard site. Therefore, proper sampling techniques areimportant to ensure a representative sample is collected for analysis. Variability is addressed bysampling different areas separately, and collecting a composite sample within each area. Inspectthe site for any obvious visual differences in soil type or condition. For example, if soil from onearea appears to be higher in clay and/or is darker than the remainder of the site, sample this areaseparately. Within similar areas, collect a minimum of five soil samples or one sample for eachtwo acres of the orchard. Collect the samples to a depth of 12 inches (one foot). Place thesesamples in a clean plastic (not metal) bucket and mix well. Remove approximately 1 pint of soiland place it into a plastic bag to submit to the lab for analysis. Your local county Extensionoffice has additional information on soil sampling and mailers used to submit samples.Soil tests for texture, pH, salinity, phosphorus, potassium, zinc and manganese should beconducted to evaluate the suitability of a new site prior to planting trees. These analyses maycost up to $25 per sample and includes interpretations of test results and recommendations. Amore complete analysis including the parameters mentioned above as well as sulfur, organicmatter, and nitrate-nitrogen may cost up to $50 per sample. The cost of soil testing is smallrelative to the investment made in trees at the time of planting.Periodic soil sampling after the orchard is established can also help monitor changes insoil properties before they begin affecting tree growth. Maintain records of soil properties fromthe initial sampling and compare these results to samples collected every three to five years todetermine if pH, salinity, or nutrient levels are changing over time as a result of managementpractices.WATER TESTING IN UTAH ORCHARDSIrrigation water is required to ensure optimum tree yield and fruit quality. Like soils,irrigation water quality varies significantly throughout Utah. High levels of soluble salts(salinity), carbonate, bicarbonate, sodium, chloride and boron can be found in many shallowwells and surface water sources. An irrigation water quality analysis prior to establishing anorchard can indicate whether the water is acceptable, marginal or unacceptable for use on fruittrees. Water sources can also change over time. Periodic testing can indicate whether problemsare developing with a water source before they begin affecting trees.Sample irrigation water directly from the source. If the source is a well, pump the wellfor a minimum of one hour to ensure the sample is representative of the well water. Sample canalwaters at the point of diversion for the orchard.Use a clean plastic bottle with a minimum one pint volume to collect the sample. Rinsethe bottle a minimum of three times in the water before taking the sample. Cap the sample andmail or deliver it to the lab immediately. If necessary, keep the sample refrigerated until it can betaken to the lab. Irrigation water samples should be analyzed for salinity, carbonate andbicarbonate, sodium, calcium, magnesium, boron, chloride and sodium adsorption ration (SAR).These analyses may cost $18 per sample and include an evaluation of the suitability of the watersource for use in irrigating orchards.Figure 1. Photograph and diagram indicating the correctlocation to collect leaf samples.PLANT TISSUE TESTING IN UTAH ORCHARDSLeaf analysis is the most reliable indicator of fruit tree nutrient status. Leaf analysis isalso useful in differentiating between nutritional problems and disease symptoms. Considerableresearch has been conducted to identify critical nutrient concentrations in leaves of various fruittree species. When properly sampled and analyzed, leaf tissue nutrient levels can be compared tohistoric critical nutrient concentrations to identify deficient, adequate and excess levels.Leaf nutrient concentrations vary throughout the growing season. For routine tissuetesting in orchards, leaf samples should be collected between July 15 and August 15. This is thestandard growth window where most critical nutrient concentration research information isavailable for Utah. When sampling an orchard, select five trees of the same variety within ablock no larger than five acres. Do not include trees with obvious visual problems. Sampleproblem trees and different varieties separately. Randomly collect 10 to 20 leaves per tree fromshoulder height, selecting leaves from the center of the current season’s growth (Figure 1).Tissue analysis can also be used to diagnose problems occurring during the growingseason. If one or more trees appear abnormal and samples cannot be collected during the normalJuly 15 to August 15 window, thecollection of paired samples greatlyenhances the diagnostic value oftissue testing. Paired samplingallows the analytical lab and growerto compare the nutrient status ofhealthy trees to abnormal ones attimes outside the normal samplingwindow. To collect paired samples,select 10 to 20 leaves from severalabnormal trees and combine theminto one composite sample. Alsocollect 10 to 20 leaves from normaltrees of the same variety growing inthe same area and combine theseinto one composite sample.Leaves are typicallycovered with a fine layer of dustthat may influence the tissueanalysis.  Rinse collected leavesfor 30 seconds in clean runningwater and allow to air dry beforesubmitting samples for analysis.Mail or transport the samples assoon as possible after collection. Ifdelayed, refrigerate samples.Request a complete analysis ofeach fruit tree tissue sample,including nitrogen (N),phosphorus (P), potassium (K),calcium (Ca), magnesium (Mg),sulfur (S), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn). A complete analysis may cost$25 per sample and includes interpretations and fertilizer recommendations.FOR MORE INFORMATIONThe Utah State University Analytical Laboratory regularly tests soil, irrigation water andplant tissue samples from orchards. Contact your local county Extension office for copies of labinformation forms and mailers, or contact the USU Analytical Laboratory directly at (435) 797-2217. Other labs in your area may also analyze samples. Check the yellow pages and contact thelab before submitting samples to make sure they are familiar with orchard sampling andinterpreting the results.FOR FURTHER READINGMills, H.A. and J.B. Jones. 1996. Plant Analysis Handbook II. A practical sampling, analysisand interpretation guide. Micro Macro Publishing, Jefferson City, MO.Righetti, T.L., K.L. Wilder, and G.A. Cummings. 1990. Plant analysis as an aid in fertilizingorchards. Chapter 22 in R.L. Westerman (Ed) Soil Testing and Plant Analysis. SoilScience Society of America Book Series No. 3. Soil Science Society of America,Madison, WI.Walker, D.R., R.L. Smith, S.D. Seeley, R.E. Lamborn, A.R. Halvorson, and J.L. Anderson.1979. Fertilization of fruit crops. Utah State University Extension Leaflet #106.Walker, D.R., A.H. Hatch, and T. Lindstrom. 1989. Fertilization of fruit crops. Chapter 4 in TheUtah Fertilizer Guide. Utah State University Extension, Extension circular 431.Utah State University is an affirmative action/equal opportunity institution. Issued in furtherance ofCooperative Extension work. Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department ofAgriculture, Jack M. Payne, Vice President and Director, Cooperative Extension Service, Utah StateUniversity. (EP/12-01/DF)

Soil, Water  and Plant Tissue Testing in Utah Orchards

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Soil, Water and Plant Tissue Testing in Utah Orchards

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