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