Residuals and manure management for environmental and agronomic benefits
This presentation is the property of its rightful owner.
Sponsored Links
1 / 22

Residuals and Manure Management for Environmental and Agronomic Benefits PowerPoint PPT Presentation


  • 81 Views
  • Uploaded on
  • Presentation posted in: General

Residuals and Manure Management for Environmental and Agronomic Benefits. Olawale O. Oladeji Soil and Water Science Department University of Florida. Residual Application Rates. Meet N needs of plants (N-based) and avoid excessive N that can pollute the ground water.

Download Presentation

Residuals and Manure Management for Environmental and Agronomic Benefits

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Residuals and manure management for environmental and agronomic benefits

Residuals and Manure Management for Environmental and Agronomic Benefits

Olawale O. Oladeji

Soil and Water Science Department

University of Florida


Residual application rates

Residual Application Rates

  • Meet N needs of plants (N-based) and avoid excessive N that can pollute the ground water.

  • N-based rates often provide and load soils with excessive P

  • Excess P:

    • Not harmful to plants

    • Potential environmental impact


Phosphorus loss

Phosphorus Loss

  • Sandy soils of Florida sorb P poorly and surround P sensitive water bodies


Water treatment residuals wtrs

Water Treatment Residuals (WTRs)

  • Generated with Al and Fe coagulants

  • Mostly Al and Fe hydroxides

  • High affinity for phosphorus !!!


Wtr rates

WTR Rates

  • Land application of WTRs could lead to excessive immobilization of soil P and Al toxicity

  • Negative impact of WTRs calls for best management for environmental and agronomic benefits

Inadequate WTR

Excess WTR

Deficiency

(P loss)

Deficiency

(Excessive immobilization)


Soil test methods

Soil Test Methods

  • A good soil test could be a tool to identify environmental and agronomic thresholds to arrive at optimum rates of WTRs and P sources.

  • Conflicting results from the use of conventional soil test methods (e.g., Mehlich 1) in studying soils receiving WTR call for identifying suitable soil test methods.


Hypotheses

Hypotheses

  • There exist suitable soil test methods for P bioavailability in soil receiving organic sources of P and WTRs.

  • (1)P-based rates of different organic sources of P without WTR optimize P uptake.

    (2)N-based rates of different organic sources of P with WTR optimize P uptakes.

  • Amendment rates selected in (II) that optimize P uptake also minimize leaching and runoff P.


Objectives

Objectives

  • Determine suitable soil test methods for P bioavailability in soils amended with different P sources and WTR.

  • Determine the rates of WTR and organic P sources that optimize plant P uptake while minimizing environmental P hazards.

  • Evaluate the impacts of selected amendments rates (WTR and organic P sources) on leaching and runoff P.

  • Validate the expected impacts of selected amendment (WTR and organic P sources) rates on P uptake and P loss in field settings.


Experiment i glasshouse study

Objectives:

Determine suitable soil test methods for P bioavailability in soil treated with different organic sources of P in the presence and absence of WTR

Determine the rates of organic sources of P (amendments), with and without WTR, that optimize P uptake

Design:

4X2X3 factorial experiment plus 1 control in randomized complete block with 3 replicates

Factors:

4 P Sources (Poultry manure, Boca Raton Biosolids, Pompano Biosolids, TSP)

2 P Sources rates (N- and P-based)

3 WTRs rates (0, 1.0 and 2.5% oven dry basis)

Test plants:

Bahiagrass (Paspalumnotatum Fluggae) follow by Fescue grass (Festucaovina “Glauca”)

Experiment I: Glasshouse Study


Glasshouse experiment

Glasshouse Experiment

Data to be collected:

  • Total P and soil test P

    (using selected extraction methods: Mehlich-1, Water extractable P, Fe strip P)

  • Plant dry matter yield.

  • Plant P content and uptake.


Experiment ii rainfall simulation

Experiment II: Rainfall Simulation

Objectives:

  • Evaluate impact of organic sources of P on leaching and runoff P

  • Determine the effect of WTR placement on leaching and runoff P

  • Determine the environmental threshold for P

    Design:

    4X2X2X2 factorial experiment plus 1 control in randomized complete block with 3 replicates

    Factors:

  • 4 P Sources: Poultry manure, Boca Biosolids, Pompano Biosolids, TSP

  • 2 P Sources rates :N- and P-based

  • 2 WTRs rates : 0, and 1.0%

  • 2 placement methods: Surface and Mixed


Rainfall simulation

Rainfall Simulation

  • Runoff boxes (100cm*20cm*7.5cm)

  • Surface slope (3 degree)

  • Simulated rain 7.1cm hr-1

  • Three rain events at 2-days interval

  • Runoff collected for 30 minutes

    (Leachate also collected)

Rainfall Simulator


Rainfall simulation1

Rainfall Simulation

Data to be collected:

  • Quantity of runoff and leachate

  • Total runoff and leaching P

  • Runoff and leaching dissolved P


Expected results

Expected Results

  • N based rates with WTR and P based rates expected to give soil test P (STP) below the change point (environmental threshold)

  • N based rate without WTR is expected to give STP and RDP above the change point

  • Environmental threshold STP is expected to be about three times agronomic optimum

Environmental threshold

Agronomic threshold

RDP (mgL-1)

Change point

A

E = ~3A

Soil test P


Experiment iii field experiment

Experiment III: Field Experiment

Field validation of impacts of selected rates and sources of P and WTR on P loss and uptake

Design: 4X2X3 factorial experiment plus 1 control in randomized complete block with 3 replicates

Factors:

  • 4 P Sources: Poultry manure, Boca Biosolids, Pompano Biosolids, TSP

  • 2 P Sources rates :N- and P-based

  • 2 WTRs rates (0, and 1.0%)

    Test plant: Bahiagrass


Field experiment

Field Experiment

Data to be collected:

  • Runoff and leaching P

  • Plant dry matter yield

  • Plant P uptake

  • Total P and soil test P using selected extraction methods (Mehlich-1, Water extractable P, Fe strip P); oxalate extractable P, Al, Fe,).


Preliminary results

Preliminary Results

  • WEP and ISP are better correlated with P uptake than Mehlich-1

  • WEP and ISP are potential soil tests for P in WTR treated soils.


Preliminary results1

Preliminary Results

  • Potential P loss (readily desorbable P) is lower in WTR treated soil as indicated by the WEP and ISP

With WTR

Without WTR


Preliminary results2

Preliminary Results

  • DPSox = (Ox-P) X 100

  • α(Ox-Fe + Ox-Al)


Preliminary results3

Preliminary Results

Nair et al., 2004

  • Treatments without WTR have %DPSox above the change point.

  • Treatment with WTR have %DPSox below the change point (environmental threshold).

calculated using oxalate extraction (DPSox) for soil receiving

different P sources with and without WTR.

35

30

20

25

15

With WTR

WEP (mg/kg)

10

Control

5

Without WTR

0

0

20

40

60

80

100

120

%DSP(OX)


Impact of wtr on soil and plants

Impact of WTR on Soil and Plants

  • WTR addition lowers DPSox without significantly impacting the plant


Thanks

THANKS


  • Login