Nitrogen Use Efficiency, Nitrogen Fertilizers, NUE, Nitrogen and the Environment    Magruder Plots
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  Plot Plan
Magruder Plots, 120 years
Magruder Plots, Long Term winter wheat experiment 1892 Magruder Plots, long term winter wheat Magruder Plots, pre 1947 Magruder Plots, pre 1947, long term winter wheat A.C. Magruder
July 1, 2013
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October 9, 2012 - Wheat
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2010, 2006, 2005, 2004
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1930's
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August 2014,

Hi Bill,

Quick question. On the Magruder plots receiving chemical fertilizer, did it ever receive applications of sulfur as part of a superphosphate?

Bailey Norwood
Associate Professor
Department of Agricultural Economics
Oklahoma State University
bailey.norwood@okstate.edu

(Response:),

Years ago, inorganic P was sold as “ordinary super phosphate”  which is 20%P2O5 and 12%S.  OSP has been available since the 1840’s.  TSP (46% P2O5) has no S.  It completely replaced OSP in the early 60’s because the shipping industry, could move more and per pound of "actual P" for a lot less.    Nonetheless, your question is a good one because OSP does have benefits, especially where S deficiencies exist.  When I was in Central America, based in Guatemala, we added gypsum to the TSP as it helped in 2 ways.  First it could assist with the S demands that did exist on volcanic ash soils, and it also assisted in forcing P precipitation as DCP and/or DCPD (di calcium phosphate and di calcium phosphate dehydrate).  The latter two forms are more available, and slowly available with time versus a TSP product that will dissociate into highly available ortho phosphate P forms, but that are more easily fixed in volcanic ash soils (allophane and immogolite).  Thus the reason why OSP works better in volcanic ash soils.   But…. the mystery continues….  TSP could not have been applied in the Magruder Plots before 1959 (date of invention in Bartlesville, OK… see below).   and…. therefore, we have to assume that OSP was used from 1892 to say 1960.  So….. SULFUR had to have been added to the P plot (1892-1960), simply because the availability of an inorganic P source (as a commercially available fertilizer) would have been OSP.     I used to have all of the records for the Magruder Plots stored in my office until I informed the Library.  Whence upon they immediately came over boxed it up, carted it off and apparently archived everything.  It could be in that same warehouse where the Arch of the Covenant from Indiana Jones is stored!   They even took some of my stuff.  I still have the original AC Magruder picture that “we” soil fertility guys hand down to the next in line who will very soon be Dr. Arnall.   Fun question, and hopefully a fun answer.  I will post this to our Magruder site so it isn’t forgotten. 

Thanks! bill
Magruder Plots, Oldest Long-Term Winter Wheat Experiment in the World
Dr. A.C. Magruder, 1867-1924

LATITUDE: 36, 7.1844, N
LONGITUDE: 97, 5.3190, W

Annual Rainfall:  33 inches per year (825 mm)
Mean Annual Temp:  59F,  15.5C
Kirkland silt loam (fine, mixed, thermic Udertic Paleustolls)

Publications

Nitrogen Balance in the Magruder Plots Following 109 Years in Continuous Winter Wheat  J. Plant Nutr.  26:1561-1580. (pdf)

Use of Stability Analysis for Long-Term Soil Fertility Experiments.  Agron J. 85:159-167

The Magruder Plots, Untangling the Puzzle.  (Agron J. 1191-1198)

 

The Magruder Plots:
Environmental Production History 1892-2004


In 1892, A.C. Magruder initiated a soil fertility experiment which would be continued for more than 100 years. The Magruder plots were initially established to evaluate wheat production on native prairie soils without fertilization. Although several changes have been made to the initial trial, the Magruder plots remain the oldest continuous soil fertility wheat experiment west of the Mississippi River. One of the key findings of the Magruder Plots has been the sustained wheat production of more than 16 bu/ac, following more than 100 years without any fertilization.  Not until the last 5-10 years have we seen any benefit of K fertilization.  Early on, the response to P fertilization was notable (P-only versus the check).  As issues of sustainability and environmental safety become increasingly more important, trials such as the Magruder Plots will be further explored. 

Procedures

Initially only one plot was established to evaluate native wheat production without the application of organic or inorganic fertilizers from 1893 to 1898. From 1899 to 1929, half of the experimental area was fertilized with barnyard manure while the other half received no fertilization. In 1930, Dr. H.J. Harper established ten separate fertilization treatments on these plots which would continue to 1947. Due to a university construction decision for a new dormitory, plots from six of the ten treatments were moved (surface 0- 16") following wheat harvest in 1947 to its present location on the Agronomy Research Station (Figure 1). The subsoil at the new location was noted to be very similar to that of the original site located just west of present day Stout Hall.

Table 1. Changes in location and treatment modifications for Magruder plots,1892-present.

Year

Trts.

Nitrogen source

N rate, lb. N/ac

N rate, manure lb. N/ac

P source

Row spacing inches

Seed Rate lb/ac

Loc.

Seed Type

1892-1898

1

-

-

-

-

7

75

Old

SRWW

1899-1912

2

Manure only

-

-

-

7

75

Old

SRWW

1913-1929

2

Manure only

-

120**

-

7

75

Old

HRWW

1930-1933

10

NaNO3 (16-0-0)

33

120**

OSP (0-20-0-12S)

7

75

Old

HRWW

1934-1945

10

NaNO 3(16-0-0)

33

120**

OSP (0-20-0-12S)

14

50

Old

HRWW

1946-1947

10

NH4NO3(33.5-0-0)

33

120**

OSP (0-20-0-12S)

14

50

Old

HRWW

1948

6

NH4NO3(33.5-0-0)

33

120**

OSP (0-20-0-12S)

7

75

New

HRWW

1949-1957

6

NH4NO3(33.5-0-0)

33

120**

OSP (0-20-0-12S)

14

50

New

HRWW

1958-1967

6

NH4NO3(33.5-0-0)

33

120**

OSP (0-20-0-12S)

10

60

New

HRWW

1968-1993

6

NH4NO3(33.5-0-0)

60

240**

TSP (0-46-0)

10

60

New

HRWW

1994-pres

6

NH4NO3(33.5-0-0)

60

240**

TSP (0-46-0)

7.5

60

New

HRWW

 

Table 2. Soil fertility treatment effects on Magruder Plot wheat grain yields, Stillwater, OK, 1930-2004

 

Treatment
N-P2O
5
       K2O

lb/ac/yr

1930-37

1938-47

1948-57

1958-67     

1968-77

1978-87

1988-97

1998-04

1.  Manure  only +

 

24.1

17.5

18.0

29.9

30.2

34.1

28.0

39.5

2.

0

0

0

16.6

9.5

13.3

18.9

18.0

19.6

15.1

18.6

3.

0

30

0

21.2

15.9

19.1

21.5

18.8

22.4

14.7

20.4

4.

33*

30

0

22.6

17.2

19.8

31.7

36.0

30.5

27.4

41.7

5.

33*

30

30

23.4

17.4

19.9

29.4

33.9

30.9

32.4

44.6

6.

33*

30

30+ lime

22.3

17.3

22.5

33.0

37.6

33.0

32.9

45.6

 

 

 

 

 

 

 

 

 

 

 

 

 

Mean

 

 

 

21.7

15.8

18.8

27.4

28.9

28.4

25.1

35.1

SED

 

 

 

2.6

1.8

1.8

2.0

2.6

1.9

2.6

3.7

* N rate increased to 60 lbs N/ac in 1968.  + Beef manure applied at a rate of 120 and 240 lb N/ac every fourth year for periods 1930-1967 and 1967-present, respectively.  Lime (L) applied when soil analysis indicated a pH of 5.5 or less. 

Magruder Plots

Figure 1. Physical location and treatment structure of the Magruder Plots, 1947-present,
Agronomy Experiment Station, Stillwater

 

Figure 2.  Changes in soil organic matter (%) in the Magruder Plots, 1892-present.