The Cullars Rotation (circa 1911)

Nominated for National Register of Historical Places, April 2003

   The Cullars Rotation experiment (circa 1911) on the campus of Auburn Univesity is the oldest soil fertility study in the South and one of America's oldest, continuous field crop experiments. It is the second oldest experiment in the world involving cotton production with the nearby Old Rotation experiment (circa 1896) being older. The Cullars Rotation is located on property that was once known as the Alvis Field. Mr. John P. Alvis and his brother-in-law, Mr. J.A. Cullars, owned and farmed this property in the late 1800s. Mr. Cullars allowed Professor George F. Atkinson and others to conduct numerous early cotton fertility
experiments on this property which lead to the discovery that "cotton rust" was caused by a deficiency of potassium (early 1890s).

In 1911, the Alabama legislature appropriated funds for on-the-farm soil fertility experiments throughout Alabama. One of these experiments was on Mr. Cullar's farm near Auburn. Today, the "Cullars Rotation" is the only one of these 1911 experiments that has been continued. It studies the long-term effects of fertilization on a 3-year rotation of cotton, corn, wheat and soybean. In 1938, the "Alvis Field" was sold to Alabama Polytechnic Institute (now Auburn University) by Bessie Alvis Emerick and Lillian Alvis Miller, daughters and heirs of Mr. John P. Alvis and J.A. Cullars.

In 2001, construction of the Jule Collins Smith Museum of Art occupied most of the the Alvis Field but the Cullars Rotation with a 40-foot border is preserved for on-going research and demonstration on sustainable crop production on soils on the southern U.S. The Cullars Rotation experiment is on a Marvyn loamy sand (fine-loamy siliceous, thermic Typic Kanhapludults) soil adjacent to Auburn University campus. In recent years, the test has been maintained as a (1) field laboratory for students and visitors studying crop nutrient deficiencies, (2) source of soil and and plant material for greenhouse and laboratory research (3) site for continuous soil test calibration research, and (4) site for the study of sustainable cropping practices and soil quality.

  Experiment Design: Original design was 11 soil treatments replicated 3 times, one replicate for each of the 3 crops in the 3-yr rotation, in an ordered block design. In 1914, an additional 3 treatments (designated A, B, and C) were added to study the effect of winter legumes in the rotation. Plot size is 20 x 99 feet with a 2-foot border between each plot and 20 feet between each tier (block). The cropping area is marked by concrete pillons in the ground (328.5' x 337'). A 40-foot buffer to nearby parking lots and other development on each side is assured. Therefore, the entire Cullars Rotation occupies 408.5' x 417' (3.9± acres)

Tillage and other cultural practices: Until 1997, all crops were conventionally tilled with moldboard plowing, disking, and regular cultivation. Since 1997 and the introduction of Roundup Ready® cultivars, all crops are grown with minimum tillage. Cotton and corn are
"The Cullars Rotation is on a Marvyn loamy sand (fine-loamy siliceous,thermic Typic Kanhapludults)"
planted directly in the previous crop residue in narrow rows (20 to 30 inch rows) after paratilling (subsoiling) and using a no-till planter. Soybeans are drilled into wheat residue in June using a no-till drill. In 1999, a Liberty-Link® corn hybrid was used (Pioneer 34A55 LL) which allowed direct planting into crimson clover residue. A stacked gene cotton (Paymaster 1220BG/RR) allowed cotton to be produced with only two applications of Roundup® herbicide. Since 1996, no insecticides have been applied for insect control. This has been possible because of the boll weevil eradication program in East Alabama and the advent of Bollgard® technology. All crops are machine harvested although occasional yield estimates are made by hand harvesting portions of each plot.

Fertilization: Phosphorus as concentrated superphosphate (0-45-0) or rock phosphate, potassium as muriate of potash (0-0-60), sulfur as gypsum, and a micronutrient mix containing B, Zn, Mn, Cu, and Fe are applied to appropriate plots in split applications in the spring prior to planting cotton and in the fall just prior to planting small grain. Nitrogen as ammonium nitrate (34-0-0) is applied to appropriate plots just prior to planting cotton and corn and as a sidedress application to these crops. The small grain is topdressed with 60 pounds N per acre in late February. Recent soil test results are presented in Table 1.

  Yield Summary: Few research areas exist in the U.S. where one can see such dramatic deficiencies of plant nutrients on one site. Particularly dramatic are the plots where no soil amendment has been applied since 1911 (treatment C), the "no K" plots (treatment 6), the "no lime" plots (treatment 8), and the "no P" plots (treatment 2). Deficiencies sometimes appear on the other treatments but are less dramatic. In general, cotton is most sensitive to low soil K in this experiment while corn, soybean, and small grain are most sensitive to low soil P (Table 2).
Cotton yields also seem to be reduced more (12% of limed and fertilized control) in the no lime treatment than yields of the other crops. Without micronutrients (presumably boron), cotton lint yields were only 86 percent of the completely fertilized treatment. Other crops failed to respond at all to micronutrient fertilization. Mean yields of cotton, corn, soybean, and small grain since 1996 seem to reflect the long-term trends (Tables 3-6).

Record crop yields on the Cullars Rotation have been recorded since 1996:

  • 1540 pounds cotton lint per acre (3+ bales) on plot 10 - (1996)
  • 75 bushels soybean per acre on plot 10 - (1996)
  • 161 bushels corn per acre on plot A - (1999)
  • 63.5 bushels wheat per acre on plot 9 - (1999)
  • 64.7 bushels wheat per acre on plot 5 - (2000)
  • 70.0 bushels wheat per acre on plot 11 - (2001)

      These yields are attributed to (1) very favorable growing seasons, (2) adoption of deep tillage to disrupt traffic pans, (3) conservation tillage which allows better moisture infiltration, higher water holding capacity, and cooler soils, (4) higher plant populations , (5) timely planting, (6) better weed control especially through the new genetically modified varieties, and (7) less insect problems as a result of the boll weevil eradication program and the new Bollgard® cotton varieties.

Table 1. Mean soil pH and Mehlich-1 extractable plant nutrients and rating from 0-6 inch soil samples taken March, 1999 on the Cullars Rotation.

Plot Treatment pH Melhlich-1 extractable Nutrients*
P K Mg Ca

----------------------Rating and lb. acre(pp2m)----------------------

A No N/+legume 6.2 VH 121 H 139 H 68 900
B No N/no legume 6.1 VH 108 M 106 H 46 597
C No soil amendments 5.3 L 19 L 34 L 20 146
1 No winter legumes/+N 5.7 H 51 L 49 H 36 373
2 No P 5.8 VL 7 M 93 H 33 330
3 No micronutrients 5.9 H 78 M 89 H 49 693
4 4/3 K 6.0 VH 133 M 78 H 52 916
5 Rock phosphate 6.2 EH 400 M 95 H 64 2496
6 No K 6.0 VH 188 VL 29 H 73 953
7 2/3 K 6.0 VH 114 M 62 H 58 730
8 No lime 4.9 VH 121 M 77 L 19 226
9 No S 5.7 VH 162 M 107 H 50 660
10 Complete fertilization + micros 5.9 VH 149 M 81 H 55 856
11 1/3 K 5.9 H 99 L 48 H 55 543
LSD .05 0.3 22 32 17 376

*Rating based on cotton on sandy soils (C.E.C. <4.6 cmol/kg);
VL = Very Low
L = Low
M = Medium
H = High
VH = Very High
EH = Extremely High

Standard lime and fertilizer treatments:

  • Limed to pH 5.8 to 6.5
  •  
  • 100 lb. P2O5 per acre per 3-yr rotation
  •  
  • 270 lb. K2O per acre per 3-yr rotation
  •  
  • 90 lb. N/acre on cotton
  •  
  • 120 lb. N/acre on corn
  •  
  • 60 lb. N/acre topdress on small grain

  • Table 2. Mean Yield relative to fertilized control in selected treatment in Cullars Rotation
    Crop
    Treatment Cotton Corn Small Grain Soybean

    ----------------------------% relative yield --------------------------------------

    No lime, pH=4.9 12 42 39 19
    No K 8 44 73 58
    No P 45 42 43 48
    No S 87 93 100 86
    No micronutrients 86 99 96 94
    LSD .05 27 32 25 35

    Table 3. Cotton lint yield on the Cullars Rotation, 1996-1999

    Plot Treatment Cotton Lint Yields
    1996 1997 1998 1999 4-yr ave.

    ----------------------------pounds/acre---------------------------------

    A No N/+legume 1310 970 1064 400 940ab
    B No N/no legume 1340 770 990 480 900ab
    C No soil amendments 0 0 0 0 0 d
    1 No winter legumes/+N 870 1310 900 610 920ab
    2 No P 520 480 720 280 500 c
    3 No micronutrients 1090 1120 980 590 950ab
    4 4/3 K 1290 1000 850 590 930ab
    5 Rock phosphate 1150 1120 810 500 900ab
    6 No K 0 0 360 0 90 d
    7 2/3 K 1580 1310 870 640 1100a
    8 No lime, pH=4.9 380 0 0 140 130 d
    9 No S 1470 880 980 500 960ab
    10 Complete fertilization + micros 1620 1080 980 700 1100a
    11 1/3 K 680 1060 770 440 740 bc
    LSD.05=300

    Table 4. Cotton grain yield on the Cullars Rotation, 1996-1999

    Plot Treatment Corn grain yields
    1996 1997 1998 1999 4-yr ave.

    ----------------------------bushels/acre-----------------------------------

    A No N/+legume 106 54 51 161 93ab
    B No N/no legume 82 30 38 130 70 bc
    C No soil amendments 0 0 0 0 0 d
    1 No winter legumes/+N 143 101 89 108 110a
    2 No P 63 55 21 39 44 c
    3 No micronutrients 137 73 75 135 105a
    4 4/3 K 132 75 69 128 101ab
    5 Rock phosphate 141 72 76 126 104ab
    6 No K 23 36 8 122 407 c
    7 2/3 K 140 89 72 135 109a
    8 No lime, pH=4.9 59 23 24 72 44 c
    9 No S 155 87 84 100 106a
    10 Complete fertilization + micros 155 87 84 100 106a
    11 1/3 K 137 94 93 64 97ab
    LSD 0.05=34bu/a


    Table 5. Soybean yields on the Cullars Rotation, 1996-1999

    Plot Treatment Soybean grain yields
    1996 1997 1998 1999 4-yr ave.

    ---------------------------bushels/acre---------------------------------

    A No N/+legume 63.8 23.3 14.1 18.2 29.8ab
    B No N/no legume 68.0 22.4 6.3 15.4 28.0 abc
    C No soil amendments 9.2 0 0 3.5 3.2e
    1 No winter legumes/+N 68.7 20.8 15.2 14.1 29.7ab
    2 No P 30.2 15.4 7.6 10.1 15.8 cd
    3 No micronutrients 70.0 23.5 16.0 13.6 30.8ab
    4 4/3 K 67.2 24.0 12.6 14.7 29.6ab
    5 Rock phosphate 68.5 21.6 16.0 14.7 30.2ab
    6 No K 37.6 23.3 5.3 8.5 18.8 bc
    7 2/3 K 66.8 22.0 12.8 15.6 29.3ab
    8 No lime, pH=4.9 24.9 0 0 0 6.2 de
    9 No S 61.7 21.9 13.6 14.8 28.0abc
    10 Complete fertilization + micros 75.1 23.3 15.8 16.1 32.6a
    11 1/3 K 62.5 20.7 10.0 15.4 27.2abc
    LSD .05=11.5

    Acknowledgement
          In addition to support through the Alabama Agricultural Experiment Station, the Cullars Rotation has received support through the commodity checkoff program of the Alabama Wheat and Grain Crops Committee and the Alabama Cotton Commission. The USDA National Soil Dynamics laboratory (Dr. Wayne Reeves and Mr. Jeffrey Walker) have provided equipment and labor to plant and harvest the test. Mr. Charlie France, Mr. Dennis Delaney, and the staff of E.V. Smith Research Center have also helped plant, maintain, and harvest.

    Table 6. Small grain yield on the Cullars Rotation, 1996-1999.

    Plot Treatment Small grain yields
    1996 1997 1998 1999 4-yr ave.

    ---------------------------bushels/acre---------------------------------

    A No N/+legume No harvest due to late freeze 13.9 11.2 17.5 14.2 c
    B No N/no legume   5.8 7.7 15.8 9.8 cd
    C No soil amendments   0 4.2 0 1.4 d
    1 No winter legumes/+N   44.2 32.7 50.5 42.5 ab
    2 No P   26.1 14.1 20.9 20.4 c
    3 No micronutrients   51.4 27.8 56.9 45.4ab
    4 4/3 K   48.0 34.2 54.6 45.6ab
    5 Rock phosphate   55.8 29.8 55.0 46.9ab
    6 No K   26.3 33.3 43.8 34.5 b
    7 2/3 K   41.6 32.2 61.7 45.2ab
    8 No lime, pH=4.9   8.8 16.5 29.9 18.4 c
    9 No S   50.8 32.7 63.5 49.0a
    10 Complete fertilization + micros   47.5 33.8 60.9 47.4a
    11 1/3 K   41.3 52.2 57.6 50.4a
      LSD .05=12


    Revised 02/04

     
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