Workgroup. UCD Alfalfa. Utilizing Plant Tissue Testing & Application Methods to Maximize Fertilizer Efficiency

Transcription

1 Utilizing Plant Tissue Testing & Application Methods to Maximize Fertilizer Efficiency Steve Orloff, Dan Putnam, and Rob Wilson UC Cooperative Extension Support from DANR Laboratory and International Plant Nutrition Institute 1

2 Favorite Quote Last time I fertilized there was a government subsidy program to help pay for the fertilizer. At that time I wasn t sure it was worth it because when we fertilized, I had to spend so much more for baling wire 2

3 Retail Price of (Over Last 6 Years) $ per ton Sep-02 Feb-03 Jan-04 Mar-04 May-05 Oct-05 Feb-06 Oct-06 Feb-07 Dec-07 Feb-08 8-Aug Jul-09 3

4 Questions 1. Does it pay to fertilize alfalfa with $1,200 a ton ? 2. Is banding more efficient than broadcasting phosphorus in established alfalfa? 3. Is it better to apply phosphorus over the winter or late in the season when the P might be running out? 4. Which is more accurate soil or plant tissue analysis? 5. Can cored-baled samples be used instead of fractionated stem samples and which one is better? 6. Which cutting is the preferred cutting to analyze? 7. Is there room for improvement with current fertilization practices? 8. UC critical levels for soil and plant tissue are lower than what many labs and consultants use. Which is correct? 4

5 Questions 1. Does it pay to fertilize alfalfa with $1,200 a ton ? 5

6 Seasonal yield increase needed to cover cost of a 100 lb/acre P 2 O 5 application at three price levels of Yield Required (tons/a) Hay Price ($/ton) $400/T $800/T $1200/T Fertilization application cost of $10 /A assumed 6

7 Seasonal yield increase needed to cover the cost of an application of at three price levels $200/ton) Yield Required (tons/a) $400/T $800/T $1200/T Application Rate (lbs P 2 O 5 /A) Fertilization application cost of $10 /A assumed 7

8 The effect of phosphorus rate and source on alfalfa yield, Lancaster CA. Lbs P 2 O 5 /A Unfertilized 100 Increase 200 Increase Cut 1 4/ Cut 2 6/ Yield (tons/a) Cut 3 7/ Cut 4 8/ Cut 5 10/ Total

9 Fertilizer Application Method Research 1) Broadcast application of granular to the soil surface; 2) Banded application of below the soil surface using a drill; 3) Banded application of to the soil surface using TeeJet StreamJet 9

10 Lassen County Sites ph of 7.3 and an Olsen P 10.1 ppm ph of 7.7 and an Olsen P 17.3 ppm Siskiyou County Sites ph of 7.4 and an Olsen P 2.4 ppm ph of 6.7? and an Olsen P 8.4 ppm 10

11 The effect of phosphorus rate on alfalfa yield Scott Valley, CA. (Olsen P 2.4 ppm) Rate (lbs P 2 O 5 /A) Untreated Cut 1 6/ Cut 2 7/ Cut 3 8/ Total Increase over Unfert

12 The effect of phosphorus rate on alfalfa yield Rate (lbs P 2 O 5 /A) Untreated Butte Valley, CA. (Olsen P 8.4 ppm) Cut 1 6/ Cut 2 7/ Cut 3 8/ Total Increase over unfert

13 Can you expect this kind of increase in yield in every alfalfa field? 13

14 Diagnosing Nutrient Status of Alfalfa Field Visual Observation Soil Testing Plant Tissue Testing Fertilizer Strips 14

15 Deficiency Symptoms 15

16 Nutrient Deficiency Symptoms in Alfalfa Nutrient Deficiency Symptoms Nitrogen Phosphorus Potassium Sulfur Generally yellow, stunted plants. Stunted plants with small leaves; sometimes leaves are dark blue-green. Pinhead-sized yellow or white spots on margins of leaves: on more mature leaves, yellow turning to brown leaf tips and edges. Generally yellow, stunted plants. Molybdenum Generally yellow, stunted plants. 16

17 Nutrient Deficiency Symptoms in Alfalfa Nutrient Deficiency Symptoms Nitrogen Phosphorus Potassium Sulfur Molybdenum Generally yellow, stunted plants. Stunted plants with small leaves; sometimes leaves are dark blue-green. Pinhead-sized yellow or white spots on margins of leaves: on more mature leaves, yellow turning to brown leaf tips and edges. Generally yellow, stunted plants. Generally yellow, stunted plants. 17

18 Diagnosing Nutrient Deficiencies in Alfalfa Visual Observation Soil Testing 18

19 NUTRIENT Phosphorus Potassium ammon.acetate Potassium Sulfuric acid Boron Soil Test Interpretation DEFICIENT <5 <40 <300 <0.1 SOIL VALUE (PPM) MARGINAL ADEQUATE HIGH >20 >125 >800 >0.4 19

20 Relative Reliability of Soil and Plant Tissue Tests Nutrient Symbol Soil Testing Plant Tissue Phosphorus P Good Excellent Potassium K Good Excellent Sulfur S Very Poor Excellent Boron B Poor* Excellent Molybdenum Mo Not Done Excellent *Good for evaluating toxicity of boron How many growers currently do soil tests? Plant tissue tests? 20

21 Traditional UC Recommended Plant Tissue Testing 21

22 Boron Interpretation of Test Results for Alfalfa Plant Tissue Samples Taken at 1/10 th Bloom Nutrient Phosphorus (PO 4 -P) Potassium Sulfur (SO 4 -S) Molybdenum Plant Part Mid 3 rd stems Mid 3 rd stems Mid 3 rd leaves Top 3 rd Top 3 rd Unit ppm % ppm ppm ppm Deficient Under 15 Under 0.3 Plant Tissue Value a Marginal Adequate Over 1500 Over 1.5 Over 1000 Over High a) Phosphorus concentration should be higher if alfalfa is cut at bud stage, 1200 ppm at mid bud, and even higher, 1600 ppm, if cut at very early bud stage. Other nutrient concentrations should be approximately 10% higher than when sampled at the 1/10 th bloom growth stage (multiply tabular values by 1.10). 22

23 Recommended Phosphorus and Potassium Application Rates Based on Results of Soil or Plant Tissue Tests Nutrient Phosphorus (P 2 O 5 ) Potassium (K 2 O) Yield Level (ton/acre) Soil or Plant Tissue Test Result Deficient Marginal Application Rate, lb/acre Adequate

24 Alternative Tissue Testing Technique Analyze Cored Bale Samples? Drawbacks to Current System Time to collect samples Must be taken prior to cutting Fractionating samples somewhat laborious Difficult to get representative sample 24

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26 Two samples collected from area of each swath One fractionated and one left as whole tops 26

27 Bales from each windrow cored before removed from field 27

28 Soil samples taken along each windrow (15 to 20 cores) Compare results from fractionated tops, whole tops, cored bales, soil samples 28

29 High Average of 117 samples over 2 years Siskiyou and Lassen Counties Average Deficient Marginal Adequate ph 7.2 Olsen P ppm 17.1 < >20 Soil K ppm 192 < >125 29

30 High Average of 117 samples over 2 years Siskiyou and Lassen Counties Average Deficient Marginal Adequate PO 4 -P ppm >1500 Mid-Stems K % >1.50 Mid-Stem Leaves SO 4 -S ppm >

31 High Low High Average of 117 samples over 2 years Siskiyou and Lassen Counties Average Deficient Marginal Adequate ph Olsen P ppm 17.1 < > Soil K ppm 192 < >

32 High Low High Average of 117 samples over 2 years Siskiyou and Lassen Counties Average Deficient Marginal Adequate PO 4 -P ppm > Mid-Stems K % > Mid-Stem Leaves SO 4 -S ppm >

33 Mid-Stem PO 4 -P P vs. Bale Total P Bale (Total P) y = x R 2 = Mid Stem P04-P (ppm) 33

34 Concern over leaf loss 34

35 Whole Plant vs. Bale P Bale P (ppm) y = x R 2 = Whole Plant P (ppm) 35

36 Bale vs. Mid Stem K Bale K y = x R 2 = MidStem K 36

37 Bale K Whole Plant vs. Bale K y = x R 2 = Whole Plant K 37

38 Mid Stem Leaf SO4-S vs Bale S Bale total S (ppm) y = x R 2 = Mid-Stem Leaf SO4-S (ppm) 38

39 Phosphorus application rate studies to determine the effect of maturity and cutting on whole tops and mid stem phosphorus levels 39

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41 Alfalfa Phosphorus Concentration in Midstems Figure 4. Alfalfa phosphorus concentration change during Change during First Harvest for 0, 30, 60, 90, and 150 first harvest growth for the 0, 15, 29, 44 and 73 kg P ha -1 lb/a rate rate treatments. Site # Midstem PO 4 -P, mg kg P 30 - P 60 - P 90 - P P Adequate PO 4 -P First bud Mid bud 10% Days, 0 = June 1 Bloom Yield Mg ha

42 Alfalfa Total Phosphorus Concentration in Whole Tops Change Figure during 5. First Alfalfa Harvest phosphorus for 0, concentration 30, 60, 90, change and 150 during lb/a rate first harvest growth for the 0, 15, 29, 44 and 73 kg P ha -1 rate treatments. Site # Whole plant total P, g kg P 30 - P 60 - P 90 - P P Adequate P First bud Mid bud 10% Days, 0 = June 1 Bloom Yield Mg ha

43 Effect of Maturity on P04 (Mid-stem Cut 1- Scott Valley, 2007)) Mid Stem PO4 (ppm) /8 5/13 5/18 5/23 5/28 6/2 6/7 6/12 6/17 Date

44 Mid Stem PO4 (ppm) Effect of Maturity and Cutting on Mid-Stem PO 4 -P Mid Stem PO4 (ppm) /8 5/13 5/18 5/23 5/28 6/2 6/7 6/12 7/9 6/17 7/11 7/13 7/15 7/17 7/19 7/21 7/23 7/25 Date 1 st Cut 2 nd Cut Date 44

45 Interpretation of Alfalfa Plant Tissue Samples Taken at 1/10 th Bloom for Whole Plant Samples Collected from Baled Hay Nutrient Phosphorus Potassium Sulfur Unit % % % Deficient <0.20 <0.80 <0.20 Plant Tissue Value a Marginal Adequate High > >0.40 a) Phosphorus concentration should be higher if alfalfa is cut at bud stage, 0.26% at mid bud, and even higher, 0.28% if cut at very early bud stage. Other nutrient concentrations should be approximately 10% higher than when sampled at the 1/10 th bloom growth stage (multiply tabular values by 1.10). 45

46 UC critical levels for soil and plant tissue sometimes lower than what many labs and consultants use. Some labs (mostly out of state use unreasonable numbers) May get an economic yield response slightly above UC values Field variability and composite samples 1735, 1380, 1320, 1180, 985 (mean = 1320) Solution??? 46

47 % Yield Potential Yield Increase from Fertilizer Application Very Low Low Medium High Very High Soil or Tissue Test Level 47

48 Questions 1. Is banding more efficient than broadcasting phosphorus in established alfalfa? 2. Is it better to apply phosphorus over the winter or late in the season when the P might be running out? 3. Which is more accurate soil or plant tissue analysis? 4. Can cored-baled samples be used instead of fractionated stem samples and which one is better? 5. Which cutting is the preferred cutting to analyze? 6. Is there room for improvement with current fertilization practices? 7. UC critical levels for soil and plant tissue are lower than what many labs and consultants use. Which is correct? 8. Does it pay to fertilize alfalfa with over $1,200 a ton ? 48