Flanary, W.E., Regional Agronomist, University of Missouri Extension
Chapple, R.W., Retired Ag Engineer, University of Missouri Extension
Crawford, J.J.W., Superintendent, Graves Chapple Research Farm, University of Missouri Extension

ABSTRACT

No-till planting is extensively used in northwest Missouri to reduce soil erosion and, as a result, the incorporation of liming materials is limited. Two treatments of a one time application of agricultural lime with an effective neutralizing material (ENM) of 377 per ton were applied at rates of 6 and 12-ton per acre. Pelletized lime with an ENM of 580 per ton was applied annually at a rate of 200 pounds of material per acre. Treatments were top-dressed without incorporation in a complete randomized block design. The change in soil pH was measured using the salt pH test. One-inch soil core segments were tested to a depth of six inches.  Soil pH measurements were taken 12, 24 and 48 months after first applications. The University of Missouri lime recommendation of 6-ton per acre produced a pH change to a depth of 2-inches in 12 months.  At 48 months, lime adjusted soil pHs to a depth of six inches. The 12-ton application treatment increased the rate of pH adjustment compared to 6-ton. The pelletized lime failed to adjust the pH as a limited amount of ENM was applied. The research was used to educate growers that liming materials can be surface applied to adjust soil pH. The information was shared during the 2005, 2006 and 2008 Graves Chapple field day with an attendance over 600 participants.

Introduction

No-till planting is extensively used in northwest Missouri to reduce soil erosion and, as a result, the incorporation of liming materials is limited. Growers questioned the value of top-dressed lime without incorporation and how quickly the pH would adjust in the plow layer.

With no-till planting systems, Buchholz (1986) and Edwards (1988) found stratification of soil pH and nutrients. Both researchers found that increased stratification of pH and nutrients did not impact crop yields.

Furthermore, Clark (1994) found no difference between corn and soybean yields in no-till with surface applied or incorporated lime treatments. Liming raised the pH in both incorporated and surface applied treatments but the incorporation raised the pH to a greater depth than surface applied applications.

Barber (1984) suggests that limestone should be applied to the plow layer before the starting of no-till or surface apply lime to correct soil acidity.  Blevins (1978) suggested that it is important to incorporate limestone before starting a no-till planting system if the soil pH is low.

The objective of this experiment was to measure the effect of two rates of top-dressed agricultural lime and top-dressed pelletized lime on pH change.

Materials and Methods

The study was conducted from 2005 to 2009 on a Salix silty clay loam located at the Graves Chapple research farm, University of Missouri, Corning, Missouri. The experiment was conducted in a randomized complete block design with three replications.

The effectiveness of liming materials refers to the ability to neutralize soil acidity. The rating system in Missouri is effective neutralizing material (ENM). ENM per ton is calculated using the calcium carbonate equivalent (CCE) and particle size efficiency ratings.  

The University of Missouri liming recommendation was 2390 ENM for the site. Six tons of agricultural lime was applied with an ENM of 2262; twelve tons of lime with an ENM of 4524; and two hundred pounds of pelletized lime was applied with an ENM of 58. The agricultural lime had an ENM of 377 per ton and pelletized lime was 580 ENM per ton. The materials were applied May of 2005 and pelletized lime was applied annually. All materials were top-dressed on the soil surface and were not incorporated.

Twelve cores were taken in each replication at 1-inch increments.  The pH was measured 12, 24 and 48 months following the initial application and the pH treatment means reported. The use of the salt pH test was used to measure pH.

Corn was planted in 2005 followed soybeans from 2006 to 2009. Plots measured 10 by 30 feet. The center two rows were measured for yields.

Yield data was analyzed by Proc ANOVA using AGSTATS (Oregon State University, 1990).

Results and Discussion

The University of Missouri lime recommendation of 6-ton per ace produced a pH change two inches deep in 12 months.  At 48 months, pH changes occurred at a six-inch depth. The 12-ton agricultural lime application rate increased the rate of pH change compared to the 6-ton agricultural lime rate. The pelletized lime failed to adjust the pH as the rate of ENM applied was not sufficient for pH change. The pH change 12, 24 and 48 months after application are shown in tables 1, 2 and 3 respectively.

Table 1. Mean soil pH change 12 months after application.

Sample Depth (inches)	Check	Ag Lime (6 tons)	Ag Lime (12 tons)	Pelletized Lime (200 lb/ac/yr)
0 to 1-inch	5.0	6.0	6.8	5.1
1 to 2-inch	5.0	5.8	6.2	5.2
2 to 3-inch	5.3	5.4	5.8	5.3
3 to 4-inch	5.5	5.6	5.8	5.6
4 to 5-inch	5.8	5.8	5.7	5.8
5 to 6-inch	5.7	5.8	5.8	5.7

 

Table 2. Mean soil pH change 24 months after application.

Sample Depth (inches)	Check	Ag Lime (6 tons)	Ag Lime (12 tons	Pelletized Lime (200 lb/ac/yr)
0 to 1-inch	5.0	6.7	6.9	5.4
1 to 2-inch	4.7	5.9	6.4	4.9
2 to 3-inch	4.9	5.6	5.9	5.0
3 to 4-inch	5.2	5.6	5.9	5.2
4 to 5-inch	5.3	5.5	5.9	5.3
5 to 6-inch	5.3	5.4	5.8	5.4

 

Table 3. Mean soil pH change 48 months after application.

Sample Depth (inches)	Check	Ag Lime (6 tons)	Ag Lime (12 tons)	Pelletized Lime (200 lb/ac/yr)
0 to 1-inch	5.4	7.0	6.8	5.3
1 to 2-inch	5.0	6.5	6.4	4.9
2 to 3-inch	4.9	6.1	6.3	4.9
3 to 4-inch	5.1	5.7	6.0	5.0
4 to 5-inch	5.3	5.7	5.7	5.2
5 to 6-inch	5.3	5.6	5.6	5.3

 

Five years of crop yields were analyzed and ANOVA indicated there was no significant difference among treatment yields within years. 

Table 4.  Crop yields across five years.

	2005 Corn (bu/ac)	2006 Soybean (bu/ac)	2007 Soybean (bu/ac)	2008 Soybean (bu/ac)	2009 Soybean (bu/ac)
Check	161	50	40	32	43
Ag Lime (6 tons)	167	51	44	32	43
Ag Lime (12 tons)	164	51	44	32	46
Pelletized Lime (200 lb/ac/yr)	154	50	43	32	42

L.S.D. 0.05 = N.S. for all years.

Research at the University of Missouri indicates different soil types have different critical pH values to produce full crop soybean yields.  The soybean critical pH value for the Mexico silt loam is 6.1; Edina silt loam, 5.3; Portageville clay, greater than 6.3 and Tipton sandy loam, 5.5. as indicated by Scharf (2007).  The Salix silty clay loam may have a low critical soil pH value. Also, Clark (1994) found no difference between corn and soybean yields in no-till with surface applied or incorporated lime treatments.

Summary

Ag lime reached plow layer depth within 48 months. The time required for the lime to move to the plow layer depth indicates that growers needing to quickly adjust soil pH, should incorporate ag lime. Lime can be top-dressed and move downward in the soil. Pelletized lime should be added at an ENM rate that is required to adjust the soil pH.

References

Barber, S. A. 1984. Liming materials and practices. p. 171-209. In F. Adams (ed.) Soil Acidity and Liming. 2nd ed. Agronomy Monogr. 12. ASA and SSSA, Madison, WI.

Blevins, R. L., Murdock, L. W. and Thomas, G. W., 1978. Effect of lime application on notillage and conventionally tilled corn. Agron. J. 70:322-326.

Buchholz, D. D., Wollenhaupt, N. C. and Smoot, R. L., 1986. Influence of tillage systems on corn yields and soil test values. p. 35-40. Ln Proc. of the Sixteenth North Central Extension-Industry Soil Fertility Workshop, Bridgeton, M0. 29-30 Oct., 1986.

Clark, K.N., Peck, T.R., and Sawyer, J.E. 1994. Comparison of plow-layer distributed and surface applied limestone for no-till crop production, 1994.  Illinois Fertilizer Conference Proceedings.  Retrieved from http://frec.cropsci.illinois.edu/1994/report4/index.htmpage.  

Edwards, D. E. and D. B. Beegle. 1988. No-till liming effects on soil-pH, corn grain yield and earleaf nutrient content. Commun. in Soil Sci. Plant Anal. 19(5): 543-562.

Scharf, P. C., (January 11, 2007) Soil  pH and lime management in Missouri. (Powerpoint). 

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