Phosphorus Solubility, Maintenance versus Buildup versus Sufficiency
   List of Phosphorus Fertilizers 

p solubility

pH 4.5  Event  Precipitate Formed

1. add fertilizer  soluble P added  -
2. 1 - 2  soluble P decreases  DCP
3. 2-3  DCP dissolves  FA
4. 3-4  FA dissolves  Variscite

Supersaturation of a band with respect to Ca (volcanic ash soils)

orthophosphate P

horizontal band

 
1. Broadcast Preplant versus Banded P (picture below)
2. Maiintenance versus Sufficiency (Roger Bray)
3. Buildup versus Maintenance

Buildup versus Maintenance
 Nebraska MEAD Study. R.A. Olson 

Phosphorus Fertilizer Carriers and Their Placement for Minimum Till Corn Under Sprinkler Irrigation.  SSSAJ, 51:1055-1062. (Horizontal Band)

Banded P (University of Minnesota, George Rehm)

4. Dual Placement, D. Leikam, L. Murphy

Dual Placement, Prairie Farmer

Sander et al. (1990) (Bands improve residual P)

5. Banding P with the Seed, SALT Article, Mead

6. Maize Yield Response as Affected by Phosphorus, Sulfur and Nitrogen as Banded Applications on a Volcanic Ash Derived Tropical Soil. Commun. Soil Sci. Plant Anal. 22:1661-1676.

(Would this not be similar to the use of ordinary super phosphate?)

S cycle on page 161 of our class book

New Leader - Not Your Father's Spreader : Common Spinner Spreader ...

Crop Physiol. Lab. at U. of Illinois placement

Schaffert Out the Back Fertilizer Disc 2x2 system - YouTube

SALT Effect
Emergence of Corn as Affected by Source and Rate of Solution Fertilizers Applied with the Seed. J. Fert. Issues. 3:18-24. (PDF)
Ammonium nutrition

Role of Ammonium Nutrition in Higher Yields, S.R. Olsen
Economic and Agronomic Impacts of Varied Philosophies of Soil Testing.  1982. Agron J. 74:492-499. R.A. Olson Web Site

P and K Fertilizers

 

Salt Rate  (N + K2O)   (why does P2O5 not enter into the salt rate?)

If you apply 50 lbs of N fertilizer as (NH4)2SO4 with the seed, what is the "Salt" rate?  50
If you apply 50 lbs of NH4NO3 with the seed (33%N), what is the "Salt" rate?    16.5

If you apply 20 lbs of P (18-46-0) with the seed, what is the "Salt" rate? 7.8  ((20/0.46)*0.18)
If you apply 10 lbs of K2O (0-0-60) with the seed, what is the "Salt" rate? 10 

(be careful with oxidation states)

Starter Fertilizers, Starter Effects  (North Carolina State University)

AVAIL (+similar products)
Humic Acids

HF Acids, Spain