Illinois Fertilizer
Conference Proceedings
January 24-26, 1994
| Home | 1994 Index | Search |
|
|
| Home | 1994 Index | Search |
Kenlyn N. Clark, Ted R. Peck, and John E. Sawyer1
The growing trend toward no-till practices by producers to reduce costs, control erosion and meet government program mandates has raised questions about the best management practices for limestone application in no-till fields. This study was planned to compare crop response, soil profile pH and chemical characteristics of surface-applied limestone and plow-layer distributed limestone in a no-till system. The effects of limestone material, application rate, surface application versus plow-layer distributed limestone, and corrected pH on crop grain yield, grain moisture, plant nutrient concentration, and the soil profile chemical characterization were investigated at the Brownstown Agronomy Research Center, on a Cisne silt loam soil (Fine, Montmorillonitic, mesic Mollic Albaqualf).
Moldboard cultivation has been the traditional form of tillage because it allows easy incorporation of fertilizers and liming materials into the plow-layer. The increasing use of reduced till, and especially no-till, tillage systems, however, brings with it the elimination of the traditional placement method for limestone. Producers must wonder if surface applications of liming materials will be as effective as incorporation at reducing soil acidity, or whether no-till fields must be occasionally tilled to add lime. Some researchers have found increases in profile stratification of nutrients and soil pH as the amount of tillage decreases or is eliminated, especially as the frequency of moldboard plowing decreases (Hoeft and Randall, 1985; Buchholz et al., 1986; Sawyer and Carter, 1989). The increased stratification or reduced distribution of nutrients and pH has not always translated into reduced grain yield, but these studies were usually confounded because the tillage comparisons were made when the tillage system itself had caused the stratification. When production levels vary with different tillage systems, it is hard to separate variations due to tillage from those caused by depth of stratification of nutrients or soil pH.
Earlier research to determine the effect of surface limestone application on crop production and soil pH distribution in continuous no-till corn has been done Zea ma s L.) (Triplett et al., 1972; Moschler et al., 1973; Blevins et al., 1978; Sutton and Trierweiler, 1990). Direct comparisons of no-till systems where the limestone was distributed through the plow layer versus applied to the soil surface, however, have not been done. Also, these studies were conducted using only surface application of N. Reed and Eckert (1989) found zones of low pH at the point of repeated injection of anhydrous ammonia in a no-till continuous corn system (pH below 5.0 after eight years with injection at the same point each year). Corn yield was not affected but elevated concentrations of Mn were found in ear leaves at silking. This research highlights the kind of problems a low pH below the soil surface can cause if only surface applications of limestone are made in a no-till system.
Not enough research has been done to I give producers the information they need on the impact of surface applications of lime on crop production in no-till systems. Before they adopt this management practice it would be helpful if they could know more about how no-till affects nutrient status in the soil. For example, for effective nutrient management, it would be useful to know if plant roots can obtain nutrients from the soil throughout the profile if only the surface few inches are maintained at the proper pH level.
In a review of limestone use and soil pH, McLean and Brown (1984) and Barber (1984) did not thoroughly address this question. Their recommendations were that either limestone should be added to the plow layer before initiation of reduced tillage or surface applications of lime should be made to correct acidity from surface applications of N fertilizers. Blevins et al. (1978) stated that if the soil pH is at a critical low level, then it may be advisable to incorporate limestone before initiation of a no-till system. However, that situation was not addressed in their research. As more producers adopt no-till in their production programs, questions about the best method of limestone distribution must be answered to ensure continued high levels of production.
The general goal of this project was to determine the effects of soil profile
pH stratification on crop production and soil chemical characteristics within
a no-till system. Specific objectives were to (1) compare profile soil pH and
other soil chemical characteristics between surface limestone application and
plow layer distributed limestone (past limestone application) in a no-till continuous
corn rotation, (2) determine plant nutrient concentration and yield with surfaceapplied
limestone and plow-layer distributed limestone in a no-till system.
This study utilized an existing liming materials experiment at the Brownstown Agronomy Research Center, located in south central Illinois. The soil type was a Cisne silt loam (Fine, Montmormillonitic, mesic Mollic Albaqualf). Past treatments included a control or no lime application, pelletized lime application at 500 and 1000 lb. CCE/acre, powdered lime at 3.25 and 4.75 tons CCE/acre, and ag-ground limestone at 6.5 and 9.5 tons CCE/acre. These treatments were replicated three times in a randomized complete block design and were applied on Aug. 20, 1985. Past tillage has been a minimum till and chisel plow. Soil pH levels (0-6 inch depth) at the initiation of the study were 4.4 to 4.5 for the control, and 6.1 to 7.1 for the high rates of powdered and ag-ground limestone.
In the fall of 1989, the plot area was fertilized with 63 lb. P2O5 and 120 lb. K2O/acre and then chisel plowed. In the spring of 1990, 72 lb. P2O5 and 230 lb. K2O/acre were applied and then the entire area was moldboard plowed (depth of 6 in.). Soybeans were grown in 1990.
Soil samples, 0-6 inch composite and by 2-inch increments to a depth of 12 inches, were collected Oct. 31, 1990 from all plots before limestone application. Limestone treatments were applied Nov. 1, 1990 to the soil surface of the three original low limestone rate treatments.
Corn was planted in the spring of 1991. Soil samples were collected April 24 and October 15: both 0-6 inch composite and by 2-inch increments to a depth of 12 inches. The yearly 1.1 ton CCE/acre surface lime application was done after sampling was complete.
The continuous corn rotation was maintained in 1992. Soil samples were taken on April 28 and October 19. The yearly 1.1 ton CCE/acre surface lime application was made after sampling was completed.
Soybeans (Hisoy 462) were planted on June 3, 1993 at a rate of 157,000 seeds per acre. Microtech at 2 quarts per acre and Sencor at 0.5 pounds per acre were applied pre-emergence on June 8. Basagran at 1 quart per acre and Poast Plus at 1 quart per acre were applied postemergence on June 22, 1993. The soybeans were harvested on October 15, 1993. Soybean yields and treatment averages are shown in Table 2.
Newly applied limestone treatments were 3.25 ton CCE/acre rate of powdered lime (99.4 percent through a 60 mesh sieve). 6.5 ton CCE/acre rate of ag-ground limestone (93.4 percent through an 8 mesh, 50.0 percent through a 30 mesh, and 33.3 percent through a 60 mesh sieve) and an annual application of 1.1 ton CCE/acre powdered lime (99.4 percent through a 60 mesh sieve) applied for three years. All treatments were kept in the same location each year. Plot size was 15 by 60 feet. The experimental design was a randomized complete block with three replications.
The intent was to measure grain yield, grain moisture content at harvest, and
nutrient concentration of leaf, whole plant, and grain samples. Soil profile
chemical characterization over time were measured for pH, Ca, Mg, and micronutrients.
The current proposed duration of this project was for three years. Continuation
of the project beyond that time may be necessary to measure longterm effects
of limestone application.
There was no significant difference in soybean yields for the different treatments in 1993. Soil pH levels from the spring of 1991 to the spring of 1993, averaged for each treatment, are presented in Tables 1a, 1b, 1c, and 1d. There was no statistically significant difference in corn yields in 1991 or 1992 between the control plots and any treatment (data shown in 1993 IFCA Proceedings). No correlation was found between treatment yields and nutrient levels or tissue elemental analysis in either year (data not shown). There was a dramatic difference in pH levels with depth that illustrated differences in surface and incorporated lime applications. Incorporated lime treatments raised the pH level throughout the plow-layer (6 inches below the soil surface) while surface applications of lime generally had their greatest effect within two inches of the soil surface. The pH levels on the treated plots were still increasing in most cases two years after application. The plots with surface-applied quarry lime at the 6.5 ton CCE level showed the slowest rise in pH in the composite samples (0-6 inch depth), but in the top two inches the pH change from the spring of 1991 to the spring of 1993 was comparable to the 0-2 inch depth change in the incorporated 6.5 ton quarry lime plots.
Other researchers have also encountered a lack of response to different lime levels. D.E. Edwards and D.B. Beegle (1988) found no statistically significant corn yield differences between limed and unlimed no-till plots in their two-year study. They cited other researchers who had found significant corn yield increases and pointed out that those researchers had done longer studies. They suggested that a lack of significance may have been due to the short-term nature of their experiment.
The same lack of response by yields to lime application was found by J. H. Grove and R. L. Blevins in two of the three years of their study. They compared no-till with moldboard tillage on fields cropped with continuous corn. There was an interaction between nitrogen rates and liming the first year lime was applied, which was also a year of severe drought. Yields were suppressed on the no-till plots with the highest nitrogen rates (336 kg/ha).
There are two factors that might explain the lack of response to liming. One
problem that a researcher might expect to find with low pH levels (below 5.5
to 5.0) would be aluminum (Al) toxicity (Tisdale et al. 1985). Com, however;
is more tolerant of elevated Al levels in the soil solution than other grains,
particularly soybeans. Some researchers have also found that Al levels with
no-till were not as high as one would expect, and they suggested that higher
organic matter content from surface residues may complex the Al and take it
out of solution. (Eckert 1985)
Results to date have found no difference between corn and soybean yields on no-till with surface applied or incorporated lime treatments. Yield variability within the replications of a given treatment may be masking overall differences. It is clear that liming has raised the pH in both incorporated and surface-applied treatments, and that incorporation raises the pH to a greater depth in the soil than surface applications. No clear relationship between soil pH and corn and soybean yields has been seen in this study.
1Kenlyn Clark is Graduate Research Assistant and Ted R. Peck is Professor of Agronomy, Dept. of Agronomy, Univ. of Il, and John E. Sawyer is Manager Agronomy Services, Growmark, Inc.
(References not listed here were cited originally in Sawyer, J.E. and T.R. Peck. 1991. Comparison of plow-layer distributed and surface-applied limestone for no-till crop production, page 95-100. In 1991 Illinois Fertilizer Conference Proceedings, Edited by R.G. Hoeft, Springfield, IL., Jan. 28-30, 1991.)
Eckert, D.J. 1985. Effects of reduced tillage on the distribution of soil pH and nutrients in soil profiles. Journ. Fert. Issues, 2:3:86-90.
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.
Grove, J.H. and R.L. Blevins. 1988. Correcting soil acidification in continuous corn Zea ma s L.): N rate, tillage and time. Commun. in Soil Sci. Plant Anal. 19(7-12): 1331-1342.
Tisdale, S.L., W.L. Nelson, and J.D. Beaton. 1985. In Soil Fertility and Fertilizers. p. 510, 4th edition. Macmillan Publ. Co. NY, NY.
