Minimizing Phosphorus Loss with 4R Nutrient Stewardship & Cover - - PowerPoint PPT Presentation

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Minimizing Phosphorus Loss with 4R Nutrient Stewardship & Cover Crops Nathan Nelson, Kraig Roozeboom, Peter Tomlinson, Gerard Kluitenberg, Phil Barnes, and Jeff Williams Kansas State University Maximizing returns and minimizing externalities

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Minimizing Phosphorus Loss with 4R Nutrient Stewardship & Cover Crops

Nathan Nelson, Kraig Roozeboom, Peter Tomlinson, Gerard Kluitenberg, Phil Barnes, and Jeff Williams

Kansas State University

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Maximizing returns and minimizing externalities

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Phosphorus loss from agriculture can degrade water quality by promoting algal blooms.

Centralia Lake, KS. Photo courtesy Kevin Price, 2012

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What is the right “place” for P?

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Best management practices to reduce P loss

Reduce Erosion (no‐till)

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Best Management Practices to Reduce P Loss

Sub‐surface application of P

P loss from Grain Sorghum in 1998 (Kimmell et al., 2001)

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Tillage effects on runoff

Increased runoff from no‐till can confound effects of

reduced erosion

4‐yr average annual runoff in sorghum‐soybean cropping systems (Zeimen et al., 2006)

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Precipitation Trends for North‐east Kansas

30‐yr average monthly precipitation at Manhattan, KS

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Can Cover crops reduce P loss?

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Research Questions (Objectives)

How does P loss from fall surface‐applied fertilizer

compare to spring injected P fertilizer (current recommended BMP)?

How does this impact crop production, nutrient use efficiency,

and profitability?

Will cover crops reduce P losses?
What are the agronomic, environmental, and economic effects
f winter cover crops in corn‐soybean rotations?
Will cover crops reduce P losses from fall surface‐applied

fertilizer?

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KAW Field Lab

Kansas Agricultural Watersheds Field Lab

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Constructed a new waterway

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Re‐grade and rebuild terraces

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Installed pipe outlets

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Installed flumes

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Installed flumes

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Methods

Small watershed/field‐scale study with natural rainfall
No‐till corn‐soybean rotation (5 year duration)
Factorial treatment structure
P fertilizer

− 0 lbs P2O5/ac − 50 lbs P2O5/ac applied in 2x2 placement − 50 lbs P2O5/ac broadcast in fall

With or without winter cover crop

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Field Measurements

Grain Yield
Water Loss (runoff)
Sediment loss
P loss
Dissolved
Total P
N loss
NO3 & NH4
Total N

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Field Measurements

Biomass production (crop and cover crop)
Nutrient content of biomass and grain
Nutrient uptake (crop and cover crop)
Nutrient use efficiency – various computations
Environmental efficiency – (Nutrient loss/grain yield)
Economic profitability

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Precipitation

through May 10 cover crop planted P fertilizer broadcast corn planted

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Runoff data from May 5, 2015

74.9 mm total precip. 31 to 41 mm total runoff

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Runoff data from May 5, 2015

a b

p < 0.10

10% reduction in total runoff

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Total P concentration in runoff (5/5/15)

p < 0.05

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Total P load in runoff (5/5/15)

p < 0.05

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Summary

Too early for any conclusions (preliminary or otherwise)
Results are highly dependent on rainfall
Requires long‐term studies to determine trends
Data collection will continue for 5 years

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Acknowledgements

Thanks to the following individuals for support

David Abel (Graduate Student/RA)
Undergraduate workers ‐ Gus Lamb, Egypt Edwards, Brett

Bullinger and Tyler Royle

Morgan Powell ‐ consulting

Funding

4R Research Fund
Kansas State Agricultural

Experiment Station

Kansas State Department of Agronomy
Kansas Soybean Commission
Kansas Corn Commission