Institute of Ag Professionals

Transcription

1 Institute of Ag Professionals Proceedings of the 2014 Crop Pest Management Shortcourse & Minnesota Crop Production Retailers Association Trade Show Do not reproduce or redistribute without the written consent of author(s).

2 How is Phosphorus Moving from Fertilizer and Manure Sources to Surface Waters PAULO PAGLIARI NUTRIENT MANAGEMENT SPECIALIST 1

3 BACK GROUND Section 1 Basic concepts of soil available P Section 2 P behavior in soil Section3 Movement of P in soils Keeping P in the field 2

4 THE SOIL P CYCLE Components Inputs Outputs 3

5 THE SOIL P CYCLE Components Inputs Outputs Organic Fertilizer Manure + Biosolids+ Residue Nutrient Addition Mineral Fertilizers Nutrient Addition Organic P - Microbial - Residue - OM Plant uptake Labile P Solution P Dissolution Precipitation Secondary Mineral Runoff Leaching Primary Mineral 4

6 INORGANIC P Agricultural soils: H 2 PO 4 - HPO 4 2- Soluble P Soil ph determines the specific form: H 2 PO - 4 when soil ph HPO 2-4 when soil ph

7 MINERAL FERTILIZER MAP NH 4 H 2 PO 4 H 2 PO 4 - DAP TSP (NH 4 ) 2 HPO 4 HPO 4 2- Ca(H 2 PO 4 ) 2 2H 2 PO 4-6

8 FERTILIZER P Don t get confused H 2 PO - 4 and HPO 2-4 is for chemistry P 2 O 5 is for fertilizer application rate This is what is shown in fertilizer bags TSP = 46% P 2 O 5 = 20% H 2 PO - 4 7

9 MINERAL FERTILIZER Solution P Adsorption Desorption Labile P NH 4 H 2 PO 4 NH H 2 PO 4 - Solution H 2 PO 4 - Always goes towards very low concentration ~ ppm Adsorption Desorption Clay Al Oxide Fe Oxide H 2 PO 4 H 2 PO 4 H 2 PO 4 8

10 MINERAL FERTILIZER Solution P Dissolution Precipitation Secondary Mineral NH 4 H 2 PO 4 NH H 2 PO 4 - O 2- Al

11 MINERAL FERTILIZER Solution P Dissolution Precipitation Secondary Mineral NH 4 H 2 PO 4 NH H 2 PO 4 - O Al Al OH OH 2 + H 2 PO 4 OH + H 2 O - H 2 O O Al Al OH O OH OH P O OH + H 2 O - H 2 O O Al Al OH O O P O OH OH 2 Labile P OH 2 Labile P OH 2 Insoluble P 10

12 MINERAL FERTILIZER Primary Mineral Dissolution Only a problem in soil with extremely high P levels Solution P Ca 5 (PO 4 ) 3 OH Rock Phosphate - xh 2 O + xh 2 O 5 Ca HPO x+1 OH - Solution P 11

13 MINERAL FERTILIZER Soil Phosphorus Buffer Capacity Solution P Solution P Adsorption Desorption Dissolution Precipitation Labile P Secondary Mineral Time Long Time Solution P Dissolution Primary Mineral Always goes towards very low concentration ~ ppm 12

14 ORGANIC P Organic Sources: Manure Biosolids Residue gc.r_pw.r_qf.&bpcl= &biw Both forms of P Organic Inorganic 13

15 MANURE P DISTRIBUTION Manure # Samples P i P o % Beef 8 Range Dairy 18 Range Swine 4 Range P i = inorganic P in manure; P o = organic P in manure 14

16 ORGANIC P Organic Sources: Manure Biosolids Residue DNA Phytate Phospholipids src=s&source=images&cd=&cad=rja&uact= 8&ved=0CAcQjRw&url=http%3A%2F%2Fco mmons.wikimedia.org%2fwiki%2ffile 15

17 ORGANIC P Plants can only use inorganic P (H 2 PO 4 - or HPO 4 2- Organic P hydrolyzed by phosphatase enzymes ph dependent 16

18 ORGANIC P HYDROLYSIS O - 6 H 2 O 6 O P OH OH O - O P OH OH Behaves as inorganic P from inorganic fertilizer 17

19 ORGANIC P IMMOBILIZATION O - 6 H 2 O 6 O P OH OH O O - P OH OH Al 3+, Fe 3+, Ca 2+ Time Adsorbed Labile Phosphate Time Precipitated Non-labile Phosphate OH OH O Al Al O OH OH P O OH O Al Al O O P O OH OH 2 OH 2 18

20 ORGANIC P IN SOLUTION Very small concentration Controlled by clay affinity, soil organic matter, ph, and organic compound ph<1.5 ph<3.5 ph<7.5-19

21 CLAY AND ORGANIC MATTER

22 CLAY AND ORGANIC MATTER 21

23 P IN CLAY 22

24 P IN CLAY H 2 PO4-23

25 P BEHAVIOR IN SOIL P in Agricultural soils ~ 50% inorganic ~ 50% organic 24

26 P BEHAVIOR IN SOIL P in Agricultural soils ~ 50% inorganic ~ 50% organic SOM C to P, C:P ratio < 200 net mineralization of organic P > 300 new immobilization of inorganic P 25

27 Organic P Mineralized (ppm) ORGANIC P BEHAVIOR IN SOIL Total Organic P (ppm) 26

28 Inorganic P Immobilization (ppm) ORGANIC P BEHAVIOR IN SOIL C:organic P Ratio 27

29 Inorganic P Immobilization (ppm) ORGANIC P BEHAVIOR IN SOIL C:organic P Ratio 28

30 Organic P (ppm) ORGANIC P BEHAVIOR IN SOIL Soil with low inorganic P Soil with high inorganic P 0 Apr May 2 Jun Jul 4 Aug Sep 6 Oct 8 Month 29

31 Soil P (ppm) EXTRACTABLE P BEHAVIOR Effect of organic amendement on soil P levels 1000 Inorganic P Organic P Organic P Applied (ppm) 30

32 Soil P (ppm) EXTRACTABLE P BEHAVIOR Effect of fertilizer addition on soil P levels 1000 Inorganic P Organic P Inorganic P Applied (ppm) 31

33 FERTILIZER P BEHAVIOR P saturated region, high concentration of H 3 PO 4 with ph 1.5 P saturated region, high concentration of H 2 PO 4 - with ph > 2.2 MAP P precipitation region, low concentration of H 2 PO 4 - ph = soil ph Formation of CaHPO 4 and Al/Fe phosphate minerals 1/4 3/4 32

34 P IN CLAY 33

35 Depth (inches) P BEHAVIOR IN SOIL Organic P (ppm) Inorganic P (ppm)

36 CLAY AND ORGANIC MATTER

37 FIELD TRIAL Experiment has been conducted at SWROC, Lamberton, MN from 1999 to present on a Normania loam initial STP 8 ppm P sources Liquid swine manure (analyzed before application) Triple superphosphate P rates 0, 90, and 180 lb P 2 O 5 ac -1 Other nutrients applied to sufficiency level P application methods Broadcast Injected (knifed for fertilizer, sweep for manure) 36

38 FIELD TRIAL Soil samples taken on fall following soybean harvest in 2000, 2002, 2004, 2006, and 2008 Samples were taken from 0-4, 4-8", and

39 Soil Bray-1 P (mg kg -1 ) SOIL BRAY-1 P NT fert:broad NT fert:knifed NT man:broad NT man:sweep 180 lb P 90 lb P 0 lb P CT fert:broad CT fert:knifed CT man:broad CT man:sweep Year

40 Soil Bray-1 P (mg kg -1 ) SOIL BRAY-1 P NT fert:broad NT fert:knifed NT man:broad NT man:sweep CT fert:broad CT fert:knifed CT man:broad CT man:sweep Year

41 Soil Bray-1 P (mg kg -1 ) SOIL BRAY-1 P NT fert:broad NT fert:knifed NT man:broad NT man:sweep CT fert:broad CT fert:knifed CT man:broad CT man:sweep Year

42 LAB STUDY Manure applied at 40 lb total P ac agricultural soils 42 manure samples (beef, dairy, swine, poultry, goat, sheep, horse) Incubated for 70 days Moisture content = 60% during incubation Determined Bray-1 P at the end 41

43 Increase in Soil Test P (ppm) MANURE P SOLUBILITY IN SOIL Pella clay loam Reactive Phosphorus Applied (lb ac -1 ) 42

44 P IN SURFACE WATERS Two forms: Reactive & Particulate Runoff water The major path for P loss Inorganic fertilizer broadcast not incorporated Manure broadcast not incorporated Soil with high levels of P Leaching P concentration in solution ~0.25 to 0.5 mg L -1 43

45 P IN RUNOFF WATER 44

46 P IN DRAINAGE WATER P concentration in drainage water is similar to P in soil solution (~ ppm) 45

47 P IN DRAINAGE WATER The problem happens when soil particles loaded with P move through preferential flow paths Manure and fertilizer can move down through soil channels 46

48 KEEPING P IN THE FIELD Two different philosophies exist for P management Build up and maintain Crop uptake Neither is better, both have pros and cons Land owner might prefer build up and maintain Renter might prefer crop uptake 47

49 KEEPING P IN THE FIELD Avoid elevating P concentration to extremely high values, e.g. 100ppm Incorporate fertilizer soon after application Incorporate manure/biosolids the same day or next after application, also good for N 48

50 KEEPING P IN THE FIELD Avoid manure winter application: 100% of inorganic P in manure can move with rain water/snow melt Best time to apply? When manure can be incorporated Tillage can help Use tillage practices that help reduce runoff Keep some residue cover 49

51 KEEPING P IN THE FIELD Cover crop? Grain crops only need up to lbs of P for maximum yield 50

52 Thank you for attending Questions? 51