Phosphorus. Joan R. Davenport Washington State University Prosser

Transcription

1 Phosphorus Joan R. Davenport Washington State University Prosser

2 Phosphorus in Plants Energy Transformations ADP/ATP, NADP/NADPH

3 Phosphorus in Plants Energy Transformations ADP/ATP, NADP/NADPH Backbone of genetic material

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5 Phosphorus In Soils Organic Matter Up to 40% P Soluble P (PO 4-3 ) Iron Phosphates Calcium Phosphates Aluminum Phosphates

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8 Challenges with P Soil Test Host of different tests Bray (common for cranberry) is highly acidic (dilute acid with fluoride)

9 Challenges with P Soil Test Host of different tests Bray (common for cranberry) is highly acidic (dilute acid with fluoride) High test values compared with other crops

10 Challenges with P Soil Test Host of different tests Bray (common for cranberry) is highly acidic (dilute acid with fluoride) High test values compared with other crops No good correlation with tissue P

11 Big Picture Issues with P Surface water contamination

12 Big Picture Issues with P Surface water contamination Farm plans/nutrient management plans

13 Big Picture Issues with P Surface water contamination Farm plans/nutrient management plans NRCS (formerly SCS) likes soil standards

14 Current Research Funded by Cranberry Institute Collaborative (MA, WI, WA) Field rate trials of P fertilizer Evaluating different soil test methods 2004, 2005,, 2006, 2007

15 Methods Dilute Salt Solution (calcium chloride) Melich-1 1 (dilute concentration of strong acids) Bray-1 1 (dilute concentration of strong acids plus fluoride) Olsen (buffered sodium bicarbonate solution) Modified Kewlona (ammonium acetate) Iron Impregnated Strips (Fe strips)

16 Extraction Method Soil Test P (ppm) Average Range Dilute Salt 1.06** Melich * Bray ** Olsen 48.32** Modified Kewlona 1.92 ns Iron Strip 38.03*

17 Plot location/type of soil effects differences are greater than fertilizer rate Extraction Method Soil Test P (ppm) Average Range Dilute Salt 1.06** Melich * Bray ** Olsen 48.32** Modified Kewlona 1.92 ns Iron Strip 38.03*

18 Next Steps Complete sample analysis Compare results with tissue test data Compare results with yield data

19 Next Steps Complete sample analysis Compare results with tissue test data Compare results with yield data So far, tissue test still appears to be the best universal indicator

20 Managing Fertilizer for Phosphorus Deficient Cranberry Beds Joan Davenport, WSU Dan Schiffhauer,, OSC

21 Research Standards for P Normal soil test range 20 to 60 ppm (UMass Chart Book)

22 Research Standards for P Normal soil test range 20 to 60 ppm (UMass Chart Book) Normal tissue test range 0.10 to 0.20 % (Davenport et al., 1995)

23 Research Standards for P Normal soil test range 20 to 60 ppm (UMass Chart Book) Normal tissue test range 0.10 to 0.20 % (Davenport et al., 1995) Minimum P needs 20 lbs/a P, 45 lbs/a P 2 O 5 (DeMoranville and Davenport, 1997)

24 FERTILIZERS NJ Fertilizers and Phosphorus, lbs/a June (bloom), November (post- harvest)

25 FERTILIZERS NJ Fertilizers and Phosphorus, 1992 P STATUS 100 lbs/a June (bloom), November (post- harvest) Tissue P (28 beds) 0.08 average range Soil test P (Bray) 20 (9 beds)

26 FERTILIZERS NJ Fertilizers and Phosphorus, 1992 P STATUS 100 lbs/a June (bloom), November (post- harvest) Tissue P (28 beds) 0.08 average range Soil test P (Bray) 20 (9 beds) Average annual P application < ½ normal rate for at least 20 years

27 Ch-Ch Ch-Ch-Changes Changes (2006) FERTILIZERS Combination of conventional blends and MAP ( )

28 Ch-Ch Ch-Ch-Changes Changes (2006) FERTILIZERS P STATUS Combination of conventional blends and MAP ( ) Tissue P (25 beds) 0.13 average range Soil test P (Bray) 67 (25 beds)

29 Leaf P (%)

30 P Fertilizer Sources Rock Phosphate Super Phosphate Triple Superphosphate (TSP) Monoammonium Phosphate (MAP) Diammonium Phosphate (DAP)

31 Leaf P (%) X/YR N/YR N/YR some TSP MAP N/YR N/YR at least 1 MAP TSP = (triple super phosphate), MAP = (mono ammonium phosphate)

32 Yield (bbl/a) State Average Marketing Order, etc

33 Ca Phosphates VS MAP

34 Lindsay and Velk, 1977)

35 P Fertilizer Sources Rock Phosphate Calcium fluoxyphosphate

36 P Fertilizer Sources Rock Phosphate Super Phosphate Triple Superphosphate Calcium fluoxyphosphate RP + Sulfuric Acid RP + Phosphoric Acid

37 P Fertilizer Sources Rock Phosphate Super Phosphate Triple Superphosphate Monoammonium Phosphate (MAP) Diammonium Phosphate (DAP) Calcium fluoxyphosphate RP + Sulfuric Acid RP + Phosphoric Acid NH4 and PO4 - crystaline NH4 and PO4 powdery

38 Lindsay and Velk, 1977)

39 Ca Phosphates VS MAP With Ca phosphates movement from one insoluble P form to another (Fe/Al) MAP readily dissolves These reactions are important in plant availability

40 Conclusions MAP increases plant available P in cranberry system MAP valuable in reversing P deficient situation Possible source of P for blended fertilizers (custom blends?)

41 Questions?