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FRUIT GROWERS LABORATORY, INC. Chad Lessard Certified Crop Advisor Director of Agricultural Services
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Talking points for interpreting your soil and tissue analysis reports Primary Nutrients and Macronutrients –N, P, K, Ca, Mg, S Secondary Nutrients and Micronutrients –Fe, Zn, Mn, Cu, B, Cl, Mo Other Chemical Properties –pH, cation exchange capacity, soil salinity, limestone Quality Control and Database Management Systems First
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Understanding Your Soil Analysis Report Soil Rpt
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Start w/ N
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Common Nitrogen Questions Q. Why is nitrate-nitrogen only analyzed in the soil and not ammonium and/or total nitrogen? A. Under conditions favoring plant growth, most forms of soil nitrogen are rapidly converted to nitrate. 2 NH 4 + + 3 O 2 2 NO 3 - + 2 H 2 0 + 4H + Q. Why is the nitrate bar blue? A. The blue bar indicates there really is no “optimum range.” Soil nitrate requirements are primarily dependant on the growth stage of your crop and soil temperature. On to N Avail
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Nitrogen Availability Nitrogen uptake efficiency during critical stages –25% when applied to the soil in a single annual application –50 – 60% when applied to the soil in 3 to 4 increments - Fertigation may be the easiest way to accomplish these incremental applications Closer look at soil N avail
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Nitrogen Availability Soil application –Average nitrogen losses = 20 – 50 percent Leaching losses - apply in short irrigation runs or at the end of a normal run Volatilization - Urea and ammonium sources should not be applied at high pH, high temperature, or on the soil surface Immobilization: significant for organic growers –High soil carbon content = Immobilization –Greater than 30:1 = N immobilization –20:1 to 30:1 = about equal mineralization to immobilization –Less than 20:1 = more rapid N mineralization OM mtrl to use
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MaterialC:N ratio Undisturbed top soil10:1 Alfalfa13:1 Manure20:1 Corn stalks60:1 Green waste80:1 Coal and shale oil124:1 Oak200:1 Spruce1000:1 Properties of Different Organic Materials *When using the high carbon content materials be sure to apply 15 – 25 pounds of extra nitrogen fertilizer to facilitate mineralization Next is P
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Common Phosphorus Questions Q. Why is phosphorus reported as P 2 O 5 ? A. Phosphorus fertilizer is sold as P 2 O 5 equivalent To convert from P 2 O 5 to P multiply by 0.436. Q. Why are there two different methods for soil P analysis? A. Depending on the pH, phosphorus exists as two different ions so there are two different extraction solutions to mimic actual P available to your crop. Dif P forms available
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Phosphorus Availability Different precipitates of P –Important to monitor pH for P Some K ?s
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Common Potassium Questions Q. Why are there two different potassium results? A. Potassium is measured in two ways. 1. Exchangeable (Exch) The exchangeable portion is the potassium available as a reserve in your soil. This moves into solution asthe soluble K is taken up. 2. Soluble (Sol) The soluble portion is the potassium most readily available. So just because
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Potassium Availability Just because your soil has a high potassium content, doesn’t mean its all available –4 general forms of K in the soil Mineral or structural = 5,000 - 25,000 ppm Fixed or difficultly available = 50 - 750 ppm Exchangeable = 40 - 600 ppm Soil Solution = 1 - 10 ppm K avail issues
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Potassium Availability Potassium in the soil is mostly available by mass flow…so… –Leaching is possible Coarse, sandy, and soils in areas of high rainfall –Can use soil or foliar applied K If foliar application use KNO 3 –Some crops can’t absorb foliar applications thus, water soluble forms of K should be applied to the soil Potassium thiosulfate appears to be the most available source Lets look @ few more K avail issues
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Potassium Availability Potassium and crop yields –Most directly related nutrient to high crop yield –High N and P increases yields as well but also increases the total demand for K to support that yield –K released from the exchangeable sites in the soil is often too slow to supply ample amounts in a high yield system On to the secondary nutrnts
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Calcium, Magnesium, Sodium and Sulfur Q. Why are these nutrients considered secondary? A. This just means they are not needed in as large of of quantities as the primary nutrients. -Although, secondary nutrient deficiencies can depress plant growth just as much as primary nutrient deficiencies. -At times, some plants can even require more S and Ca than P. Next section Chem Props
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Cation Exchange Capacity, pH, % Base Saturation, and the Lyotropic Series The “Easy” Definitions: Cation Exchange Capacity – The total amount of cations a soil can hold on its negatively charged particles (the clay and humus) pH – A measurement estimating the “active” hydrogen ions Percent Base Saturation – The percent of a certain cation that is held on the CEC in comparison to others Lyotropic Series – The order in which cations will bond with the negative charges in your soilAl3+ > Ca2+ > Mg2+ > K+ = NH4+ > Na+ Percent Base Sat
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Percent Base Saturation In a typical soil, the percent base saturation is directly related to the lyotropic series. The manner used to determine if your soil has optimal cation ratios in reserve is to measure the percent base saturation as follows: 1. Convert all exchangeable cation values to meq/100 grams and note their sum 2. Divide desired cation by total of all exchangeable cations Next prop to look at is pH
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Adjusting the soil pH changes more than just the pH ____________________________ Another ? on Micros
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Metal Micronutrient Availability If my soil pH is between 5.5 and 7 and I still have micronutrient deficiencies? –Chelated micronutrients are the way to go for soil applications –Chelated micronutrients are 6 – 10 times more effective than non-chelated micronutrients –Chelates prevent micronutrients from precipitating with other ions in the soil and allow them to move with water to the root. How they work
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Metal Micronutrient Availability How chelates work –Apply to the soil and irrigate On to plant tissue rpts
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Understanding Your Plant Tissue Analysis Report Tissue reports show
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How to use your tissue analysis report A tissue analysis report shows –The sufficiency of nutrients in your trees –Indicates the plants ability to extract nutrients from the soil Tissue exmpl
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Tissue Analysis Your Fertilization Management Report Card *Your tissue analysis report should be used along with your soil analysis data to optimize your nutrient management plan How to use this
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How to use your tissue analysis report If nutrient levels are optimal, then your nutrient management program is well balanced If not, your tissue report will indicate which changes are necessary to your nutrient management program Compensation must be made for crop nutrient removal A freq asked question
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How to use your tissue analysis report with your soils report A frequently asked question –Q. Why does my soil report show ample nutrient levels and my leaf tissue report shows deficiencies? –A. Because crops are not always capable of taking up the necessary amounts of nutrients to support their rate of growth and yield. Transition to QA / QC
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Quality Assurance / Quality Control Quality Assurance….is the overall process used to ensure accurate and precise results Quality Control…. is the actual steps taken such as blanks, standards, spikes, and duplicates used in the above process A visual example
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Quality Assurance / Quality Control We need to use QA / QC because you need to know your data is precise and accurate Imprecise and inaccurate Accurate but imprecise Inaccurate but precise Precise and accurate Reporting options
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Reporting of Testing Results Color graphic reports by mail E-mail Web reporting on FGL’s password protected website Alternatively............ Trans to database mgmt
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Database Management Systems (DMS) Use of DMS’s has been taking place for the past number of years particularly in the high-value permanent crops such as grapes and nuts Our Ag clients are now requiring more sophisticated tools to manage their analysis data What do they do?
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Database Management Systems These systems provide information that is easily accessible and accurate to assist with decisions regarding fertilization and amendment programs What else?
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Database Management Systems Tools are available to make comparisons between previous years’ performances, compare different blocks / properties and different management practices Parameters can be tailored to specific crops, crop growth stages, or even specific growers Supported dbms
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TNS (Wilbur Ellis) SureHarvest AgCode Most Company Specific Reporting Formats Fruit Growers Laboratory, Inc. Supports End
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Questions? For more info: Chad Lessard www.fglinc.com chadle@fglinc.com Fruit Growers Laboratory, Inc.
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