Rates of N-P-KTest

  The Rates of N-P-K Test was started the same year the Auburn University established a public soil testing laboratory to serve farmers and homeowners. The purpose of this experiment is to provide on-going soil test calibration and interpretation information in support of the soil testing program. The experiment is repeated at 7 locations around Alabama. The experiment consists of 6 N rates, 4 P rates, 5 Krates, and a "no lime" treatment replicated 4 times (16 treatments) on plots that are 21 x 35 feet. Crops evaluated on this experiment are as follows:

1954 - 1961 Cotton
1962 - 1964 Corn
1965 - 1969 Cotton
1970 - 1972 Cotton (residual fertility*)
1973 - 1975 Soybean (peanuts at Wiregrass Substation)
1976 - 1979 Corn
1980 - 1982 Sweet sorghum at Sand Mt., Brewton,and Tennessee Valley; Soybean and canola at Monroeville, Prattville,and Upper Coastal; Peanuts at Wiregrass
1983 - 1985 Soybean-canola at Wiregrass
1986 - 1987 Grain sorghum (residual fertility*)
1988 - 1990 Sweet potatoes residual fertility*) at Brewton, Prattville, and Sand Mt.
1989 - 1991 Small grain-tropical corn (residual fertility*) all allocations except Brewton, Prattville, and Sand Mt.
1992 - 1997 Forages (residual fertility*) at Sand Mt. and Upper Coastal Plain; Cotton (residual fertility*) at other locations
1998 - Present Fertilization resumed at all locations.
1998 - Present Cotton at Prattville,Tenn Valley and Wiregrass.
1998 - Present Hybrid bermudagrass at Sand Mt. and Upper Coastal Plain.
2000 - Present Long-leaf pine at Monroeville (no fertilizer); Fallow at Brewton.

 

 

 

 

 

 

 

 

 

 

 

(*Residual fertility = no additional P or K applied to those particular variable treatments)

Rates of N-P-K Experiment - Established 1954 Wiregrass, Brewton, Monroeville, Prattville,and Mt., Upper Coastal Plain, Tennessee Valley

Wiregrass Plot Nos.

Soybeans Before 1986

Residual P & K Since 1986

Treatment No.
Plot Numbers
Only*
N
P205
K20
 
N
P205
K20
-------------------------------------------lb/acre---------------------------------------------------
1
11
20
38
59
2
0
100
100
No N
0
100
100
2
10
27
41
60
3
30
100
100
30
100
100
3
8
22
47
61
5
60
100
100
60
100
100
4
2
26
37
49
4
80
100
100
120
100
100
5
16
32
42
53
11
0
100
100
Control
90
100
100
6
15
30
45
51
6
0
100
100
No S
150
100
100
7
5
23
35
50
12
0
0
100
No P
90
0
100
8
1
28
40
62
14
0
20
100
90
0
100
9
6
18
36
55
13
0
40
100
90
0
100
10
4
17
44
64
16
0
60
100
90
0
100
11
9
19
34
52
7
0
100
0
No K
90
100
0
12
12
25
48
54
8
0
100
20
90
100
0
13
7
31
43
63
9
0
100
40
90
100
0
14
14
24
33
57
15
0
100
60
90
100
0
15
15
13
29
46
56
10
0
100
80
90
100
0
16
3
21
39
58
1
0
100
100
No Lime
90
100
100
16B
-
-
-
-
17
0
100
100
90
100
100

* Plots at Wiregrass are numbered 1-17A and 1-17B in tow ties.

**N rates have varied due to crop and location.

Recent cropping history: 1983-1985 soybeans (Peanuts at W.G.) /rape; 1980-82 sweet sorghum; 1976-79 corn; 1973-75 soybeans; 1970-72 cotton residual.

Long-term yield records have been published in:

Cope, J.T. 1984. Long-term fertilityexperiments on cotton, corn, soybeans, sorghum, and peanuts, 1929-1982. Ala. Agric. Exp. Stn. Bul 561. Auburn University, AL.

What's Old is New Again - Historical Fertility Research Helping Establish Modern Cotton Management Strategies

Highlights

Revised 02/04

 
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