Potato Science Lecture 12
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Transcript of Potato Science Lecture 12
Meeting Nutrient Requirements of High Yielding Potato Crops
Potato Science Lecture 12Fertility ManagementIrrigated Potato Production
2Important NutrientsPrimary macronutrients
Nitrogen Phosphorus Potassium3Total potato plant N, P, and K Uptake
Days After EmergenceNutrient Uptake (lb/ac)4Total Potato Plant N, P, and K Uptake Rates at Aberdeen
Days After EmergenceNutrient Uptake Rates (lb/ac/day)KNPEarly-Season Soil Nutrient Placement
Fertilizer Placement
DryFertigationP, KNFoliarRelative Nutrient Mobility in SoilNitrogen Mobile (nitrate>urea>ammonium)Potassium moderately low mobilityPhosphorus low mobilityNitrogenNecessary for protein and chlorophyllUsed in large quantities by plantsQuantity available fluctuates rapidlyShortage associated with marked yield lossApplication important in all soils9
Soil N CycleLEACHING (NO3-)Nitrogen Deficiency Symptoms
General chlorosis (pale green color)
Younger leaves turn darker green, old leaves remain yellow
Upward cupping of deficient leaflets when severe11Potato Variety Nitrogen Response Trials Aberdeen, 2005
Soil AnalysisOne composite sample per 20-25 acres
0-12 inch sampling depth for potatoes
Combine 10-20 samples (zig-zag pattern)
Random but accurate samples13Total N Recommendations for Russet Burbank PotatoesPotential Yield (cwt/acre) Soil NO3-N (0-12 in depth)300400500600ppm---------------------------lb N/acre --------------------------0200240280320518022026030010160200240280151401802202602012016020024025100140180220Nitrogen Fertilizer Management Program
Apply up to 25-60% of N prior to planting
Apply remainder of N (40-75%) through the irrigation system during tuber development according to crop requirements
Slow release or controlled release N fertilizers applied preplant can be used to reduce N leaching
Preplant N applicationsNitrogen (partial application)25-30% on sandy soils30-40 % on sandy loam soils40-60 % on silt loams
Nitrogen fertilizers urea, mono-ammonium phosphate, ammonium sulfate, ammonium polyphosphate
16In-Season N ApplicationsBegin after tuber initiation and adjust according to tuber bulking rates and weekly petiole N concentrationsCut-off 3 to 4 weeks before vine killTarget = Total Seasonal N Requirement - preplant + sidedress applications 17Calculating In-Season N Application RatesBased on lb N/ac/day or week, which changes according to crop demand
Once tuber bulking begins, weekly crop N requirements can be estimated based on relationships between tuber growth rate and plant N uptake
Daily N uptake rates for different potato cultivars range from about 2 to 5 lb N/ac/day depending on the tuber-bulking rate
Can be applied as dry or liquid N fertilizersCalculating In-Season N Application RatesRusset Burbank requires about 3-4 lb N/ac/day (20-25 lb N/week) to prevent the loss of both N and dry matter from the tops and roots to the tubers during tuber bulking
Assuming 75-80% plant N uptake efficiency for injected N fertilizer, about 30 lb N/ac would satisfy crop N requirements for a week
Adjustments to projected rates to account for N mineralization should be based on weekly petiole nitrate tests
Total Yield Response to N for A03158-2TE and Russet Burbank at Aberdeen ID, 201346061050642320Tissue AnalysisPetiole analysis the most commonSample 4th petiole Sample under consistent conditionsDry the tissue immediatelyPrivate and public labsBase applications on sufficiency21A03158-2TE Petiole Nitrates, 2013Recommended petiole and soil (0-18 inches) NO3-N concentrations for Russet Burbank potatoes during different growth stages Tuber Tuber Sample Vegetative Initiation Bulking Maturation
------------- NO3-N (ppm) -------------
Petiole ----- 20,000-25,000 15,000-20,000 10,000-15,000
Soil > 20 20 15-20 < 1523
From Rowe, 199324Factors Affecting Petiole Nitrogen ConcentrationsPlant Factors:photosynthesisdry matter productionN metabolismtranspirationSoil Factors:temperaturemoisturemineralizationNH4+/NO3-physical conditionsRoot Factors:carbohydrate supplyroot healthroot length / depth
25Critical Time Period N builds up in (or is applied to) soil before plant uptake and may be lostImpact of Weather on Soil N Supply, Soil N Losses, and Crop N Demand Soil/Plant NSpringSummerFallPotato N UptakeSoil mineral N,Normal yearSoil mineral N,Wet springAmount of N fertilizer neededIn normalyearin year with wet springPotato Yield Response to N Fertilizer Following Fall or Spring Plowing of Alfalfa, Aberdeen 2002
Nitrogen Rate(lbs N/acre)Yield (cwt/acre)Spring plowFall plow
Potato Rotation StudyRexburg, ID 2003-2005Russet Burbank potato yields as influenced by N rates after alfalfa, wheat, or maize averaged across 2004 and 2005 seasons
83119164PhosphorusSecond most critical nutrientEssential for energy transferCritical for root growthGenerally low in soil availabilityRapidly tied up by soilManagement is long-termApplication important in all soils29
From Rowe, 199330Total Potato N, P, and K Uptake
Days After EmergenceNutrient Uptake (lb/ac)31Phosphorus and Dry Matter AccumulationDays After Emergence Accumulation/maximumdry matterP
33Soil P Buffering CapacityDepletion of solution P brings absorbed P into solution to maintain equilibriumRate of establishing new equilibrium depends on rate of desorption from absorbed forms and rate of diffusion (i.e., the withdrawal rate is proportional to the size of the bank)34Phosphorus Precipitation on CaCO3P adsorbed to CaCO3 surfaces forming ion clusters
Clusters allow for nucleation of Ca-P crystals
Common in calcareous soils of Southern Idaho35Calcite equilibrated for 10 days
0 ppm P
10 ppm P
25 ppm P
50 ppm P
100 ppm P
500 ppm P36Ammonium Phosphates
Reaction pHP Fertilizer GranuleCaHPO44H2OadsorptionprecipitationCa2+ H3PO4Recovery of Fertilizer PPlants recover 5 to 20%Remainder reacts with soil components
Residual fertilizer P builds up soil P to increase future availability
39Phosphorus Fertilizer ProgramAdequate P concentration in bulk soil to maintain optimal P concentration
Starter bands to enhance early season P availability
Maintenance / building of soil P levels40 Preplant Phosphorus Options Ammonium Phosphates - liquid and dry
Avail
Humic Acids
Controlled Release P
In-Season P Sources APP (10-34-0) and phosphoric acidBroadcast
Band42Preplant P Fertilizer Recommendations for Russet Burbank Potatoes
Apply an additional 40 to 80 lb of P2O5/acre as a starter at planting for soil test P levels below 30 ppm.Add 25 lb P2O5/acre as a starter for additional 100 cwt/acre above 400 cwt/acre.Soil Test P(0-12 inch depth)ppmPercent Free Lime------------ lb P2O5/acre ----------------0 4 812Dry Matter Balance
Dry Matter Balance (total / tubers) Average P in leaves (%)Y = 0.76X 0.7r2 = 0.67(0.22)Westermann and Kleinkopf, 19850.22% P = sufficiency levelPhosphorus FertigationMaintain petiole P concentration above 0.22% through tuber bulking30 to 40 lb P/A in late July can increase total P uptake 4 to 5 lb/ac
Typically use APP (10-34-0) or Phosphoric acid45PotassiumUsed in large quantities by plants
Important in translocation of nutrients
Easily leached in sandy soils
Some soils naturally low
Application important in all soils46Total Potato N, P, and K Uptake
Days After EmergenceNutrient Uptake (lb/ac)47
48Forms of Potassium in SoilMineral5,000 - 25,000 ppmNon-exchangeable50 - 750 ppmExchangeable40-600 ppmSolution1-10 ppm49K Absorption by Plants Primarily by diffusion and mass flow
Related to K intensity (solution K)
Diffusion : 85 - 95% of K uptake
Mass Flow : 5 - 10% of K uptake
K quantity (Q) = exchangeable KRelationship between STKC and K DiffusionSTKC, ppmK Diffusion ppm / day>
y = 0.0138x 0.30r2 = 0.64>Relationship between STKC and slow-release K from soil extractsSTKC, ppmSlow Release K, ppm / day>
175Soil K Recommendations Critical STKC for potatoes = 175 ppm
About 4.6 lb K2O/ac required to raise STKC 1 ppm per 1 foot of soil (without fixation)
Estimated K fixation 5% at 150 ppm STKC and 27% at 25 ppm STKCPotassium fertilizer recommendations
ppm ------------- lb K2O/ac ------------- (0-12 1nch) 300 400 500 600 Soil Test K Yield Goal (cwt/ac)Potassium Fertilization GuidelinesProbability of a K response: loamy sand > sandy loam > loam > silt loam Slight advantage for K2SO4 over KCl (@rates > 200 lb K2O/A) for:specific gravitiesNo. 1s55Potassium Fertilization GuidelinesBanded K not as effective as broadcast K K in starter band should be < 50 lb K2O/ac (salt effect)
Avoid high (>300 lb K2O/ac) spring applicationsyield reductions observed with spring applications of 400-600 lb K2O/ac
higher rates should be split fall/spring56Potassium Fertilization GuidelinesPreplant K more effective than applying most of the K in-season (fertigation)
Fertigation - no consistent difference between K sources (KCl, K2SO4, KTS)
Avoid large (>50 lb K2O/A) single fertigation applications57Potassium Fertilization GuidelinesUse petiole testing to determine K fertigation requirements
Maintain > 7.0 - 7.5 ppm K in fourth petiole
Cut off K fertigation 30 days before vine kill to avoid reducing specific gravity58N and P Fertilizer Effects on Specific Gravity of Russet Burbank Potatoes, Aberdeen (1985)N Applied (lb N/acre) P Applied (lb P2O5/acre)PotassiumDeficiency Symptoms
Symptoms appear on young, full-sized leaves
Leaflets become rugose (crinkled)
Leaves take on a scorched appearance with black pigmentation and necrotic (dead tissue) edges60
Potassium Deficiency Symptoms61
http://www.microessentials.com/62
Secondary Macronutrients
Sulfur Calcium Magnesium63SulfurImportant as a component of proteinsOften naturally availableMany sources Fertilizer by-product Water supply Organic matterSome soils inadequateIdeally, 15 ppm or greater 64SulfurDeficiency SymptomsGeneral chlorosisSimilar to nitrogen deficiency except young leaves remain yellow over timeLeaflet yellowing is uniform and general>0.20% S in petiole - sufficient65
Sulfur deficiency Symptoms66CalciumImportant for cell wall integrityAbundant in arid soilsIdeally, 300 ppm or greater Passive uptake - moderate solubilityPoor transport under cool conditionsFoliar applications not transported to tubersApplication necessary in acid soils for pH adjustment
67Calcium Deficiency SymptomsSymptoms appear on youngest leaves firstLeaflets cup upwardBrown spotting on leafletsLeaflets eventually dry up and become brown if symptoms are severe>0.60% Ca in petiole - sufficient
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Calcium Deficiency Symptoms
69MagnesiumComponent of chlorophyllDerived from native rocksSome soils deficientIdeally, 100 ppm or greater Application commonly necessary in acidic soils
70MagnesiumDeficiency Symptoms
Symptoms appear first on young mature leavesGeneral chlorosis with veins remaining greenLeaflets near growing point remain greenInterveinal necrosis causes scorched look>0.30% Mg in petiole - sufficient
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Mg Deficiency Symptoms72Micronutrients Boron Copper Iron Manganese Molybdenum Zinc73MicronutrientsEssential as activators and for enzyme systemsAvailability affected by pHBoron naturally low in some soilsCopper often deficient in muck soilsIron, manganese, and zinc unavailable in alkaline soils
74IronDeficiency Symptoms
Growing point and young leaves become yellow or in extreme cases, whiteUsually not accompanied by necrosisVeins and leaflet ends remain green> 50 ppm Fe in petiole sufficient> 4 ppm Fe in soil - sufficient
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Iron Deficiency Symptoms76
http://www.microessentials.com/77ManganeseDeficiency Symptoms
General yellowing of plantLeaves cup upwardBrown spotting occurs on leaflets, especially along larger veins and mid-ribs> 40 ppm Mn in petiole sufficient> 6-8 ppm Mn in soil - sufficient
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Manganese Deficiency Symptoms79ZincDeficiency Symptoms
Little leaf occurs, showing as small, narrow, chlorotic leafletsLeaflets cup upwardTip-burn on leafletsLower leaves bleach and fall from plant> 20 ppm Zn in petiole sufficient> 1.5 ppm Zn in soil - sufficient
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Zinc Deficiency Symptoms81Fertility Management PlanPrior to and at plantingSoil analysisPreplant fertilizer applicationsNitrogen (partial application)25-30% on sandy soils30-40 % on sandy loam soils40-60 % on silt loamsPhosphorus (broadcast and banded)Potassium (broadcast)Micronutrients, as needed82Fertility Management PlanDuring early tuber bulking
Continue petiole testingContinue seasonal applications of NCorrect deficiencies of P, K and microsFertigation for P (30-40 lbs P/ac) and K (