INNOVATIVE NUTRIENT MANAGEMENT TO

IMPROVE WATER QUALITY

Minnesota Agricultural Water Resources Coalition

Eligible ActivitiesThe program objectives are to implement and evaluate field scale on-farm nutrient management methods to evaluate/demonstrate nutrient efficiency and to minimize nutrients entering ground and surface water. Projects should demonstrate and promote efficient use of agricultural nutrients resulting in economic benefits for production agriculture while providing water quality improvements as a result of implementing such practices.

Basis for this trial began several years ago

-Erosion concerns with conventional tillage

-Fertilizer placement concerns with reduced tillage systems

-P Tests (P1 test) 15 to 19ppm medium

-K Tests (Bray K) 63-91ppm low to medium

-Most of the potassium in this field is concentrated in the top two inches of the topsoil profile.

Soil samples collected in 2010

Top 2 inches 151ppm

Middle 2 inches 83ppm

Lower 3 inches 56ppm

A stratification test indicated the following potassium soil test levels

High Rate Phosphate—60 lbs of P205 per acre (120 lbs 11-52-0) Potassium—144 lbs of K20 per acre (240 lbs 0-0-60)

Low Rate Phosphate—30 lbs of P205 per acre (60 lbs 11-52-0) Potassium—72 lbs of K20 per acre (120 lbs 0-0-60)

Phosphate and Potassium fertilizer application rates

There was a zero phosphate and potassium rate for each tillage treatment in all replications.

-Nitrogen was applied as Anhydrous Ammonia at a rate of 105 lbs per acre

Nitrogen application

-Phosphate and potassium were injected in the strip till and vertical tillage systems using a Bourgault fertilizer air cart. The tool bar was raised out of the ground to broadcast fertilizer for the conventional tillage plots.

-RTK guidance was used to steer the tractor.

Phosphate and potassium application

Conventional tillage was done with a Kent field cultivator.

The seed bed was prepared with a single pass which also incorporated the phosphate and potassium.

-Strip tillage was done with a Dalton anhydrous tool bar equipped with coulters and covering disks.

-This was the only tillage pass done on the strip till trials.

Vertical tillage, which is a series of coulters on a tool bar, was done following strip tilling.

Starter fertilizer consisted of 5 gallons of 28% N solution and 2 gallons of ATS per acre placed in a surface band 2 inches to the side of the seed. No phosphate was included in the planter applied starter.

The planter used to plant the trial was a Kinze 16-row planter equipped with row cleaners.

Steering of the planter tractor was done using RTK guidance to plant directly over the fertilizer band.

-The fertilizer was injected May 5, 2011.

-The planting date was May 16th.

-The base hybrid in the plot is Dekalb 50-66 and the refuge hybrid is Dekalb 52-62.

-The center 8 rows of each plot were harvested for yield determination.

-The Dekalb 50-66 was the harvested hybrid in all three replications.

Field prior to beginning trial.

Previous crop was no-till soybeans

following corn. All field work was done

in the spring of 2011.

Equipment used to inject phosphate,

potassium and nitrogen. RTK

guidance is steering

the tractor.

Field following planting in the strip

till area.

Conventional Tillage

No P & K Fert

Rep 1 190.0

Rep 2 203.6

Rep 3 197.5

Average 197

Strip Till No Fert

Rep 1 183.0

Rep 2 202.2

Rep 3 197.4

Average 194.2

Strip Tillage followed by

Vertical Tillage

No Fert

Rep 1 190.2

Rep 2 196.2

Rep 3 196.4

Average 194.3

Conventional Tillage

Low Rate of P & K

Rep 1 201.7

Rep 2 208.3

Rep 3 202.5

Average 204.2

Strip Till Low Rate

Rep 1 200.4

Rep 2 204.9

Rep 3 205.5

Average 203.6

Strip Tillage followed by

Vertical Tillage

Low Rate

Rep 1 195.3

Rep 2 205.8

Rep 3 205.1

Average 202

Conventional Tillage

High Rate of P

& K

Rep 1 198.0

Rep 2 207.7

Rep 3 204.7

Average 203.5

Strip Till High Rate

Rep 1 200.4

Rep 2 210.1

Rep 3 209.4

Average 206.6

Strip Tillage followed by

Vertical Tillage

High Rate

Rep 1 203.6

Rep 2 209.6

Rep 3 209.7

Average 207.6

Yield differences across all treatments were small. Even the zero rate of phosphate and potassium produced excellent yields.

Conclusion

Lynn LagerstedtDecember 5, 2011

-Tillage, on all treatments, using a shank with a knife and covering disks could have incorporated upper level soil fertility.

-Relatively moist conditions in early season could have favored root uptake of nutrients in the top few inches of soil.

-This farm has an excellent yield history.

Possible reasons