Illinois
Fertilizer Conference Proceedings
January 23-25, 1995
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Lyle Paul1
As grain producers change their tillage and planting operations to include more reduced tillage or to using no tillage prior to planting, there is less opportunity for mixing nutrients into the soil. Some advocates of zero-till have said that the benefits of zero-till are increased if the soil is left undisturbed for a period of time (several years). They feel that the benefit to not disturbing the soil is greater than any negative effect from not mixing the fertilizer into the soil. There has been concerns expressed by others that occasionally fertilizer needs to be mixed into the soil to get maximum yields.
The objectives of this study were to determine:
This study is a randomized complete block design with four replications with corn and soybean crops being planted each year in a corn-soybean rotation. The initial lime treatments were to add enough lime to raise the pH to 6.5, add 1/3 the amount of lime to raise the pH to 6.5 or add no lime. The fertilizer treatments were to add nothing, add phosphorus to raise the soil Pl test to 50 and potassium to raise the soil K test to 300 and then add no more fertilizer or to add maintenance applications of fertilizer after the original application. One-half of the plots were disked and plowed after liming and fertilization and other one-half were untilled. In succeeding years all plots have been no-tilled.
These plots were established on Flanagan silt loam and Drummer silty clay loam. The average initial soil test levels are pH-5.6, P1-39, and K-225. Previously this field has been in a corn and soybean rotation with minimal fertilizer added for a period of years.
To make the needed pH changes, powdered limestone that would pass through a 200 mesh screen was applied to the individual plots according to the experimental plan and to the average of the four initial incremental soil tests of the individual plots. Fertilizers in the forms of 0-46-0 and 0-0-60 were also applied to the individual plots according to the plan design and soil test. After fertilizer application in the spring of 1991 the plots selected for incorporated fertilizer were disked once and moldboard plowed. After plowing, the incorporated plots were disked twice and was a row cultivation in 1991. The entire study area was row cultivated using a zero-till cultivator. The only other soil disturbance has been the annual shallow injection of 28 % UAN as the nitrogen source for the corn crop.
In 1994, the corn in the study area was planted on May 9, 1994. The variety used was Pioneer Hybrid 3417 planted at 30,900 seeds per acre in 30 inch rows. Nitrogen was applied on June 13 at 180# of nitrogen per acre. The nitrogen was in the form of 28 % nitrogen and was shallowly injected at a depth of about 3" inches using a knife applicator with the knives on thirty inch centers.
The soybean crop was planted on May 12,1994. The variety was DeKalb Genetics variety CX232. The beans were planted with a John Deere No-till drill in seven & one-half inch rows at a seeding rate of 180,000 seeds per acre.
Roundup and 2,4-D were applied to all of the study area prior to planting. Pre-emergence herbicides were used in both crops. With the dry conditions in May, less than adequate weed control was achieved.
Incremental soil tests were pulled in the falls of 1993 and 1994 following
harvest each year. The data for the change from the original soil tests at each
of the increments for the fall 1993 samples is reported in tables
2, 3, 4
and 5. The samples from 1994 are at the
laboratory at the time of the paper being written and the results will be reported
in the oral presentation.
Yields in 1994 (Table 1) may have been adversely affected by the lack of effective weed control. The corn yields showed a response to the fertilizer and lime applications, but not to lime applications alone. The soybean crop yields did not seem to reflect lime or fertilizer applications in 1994, although the yields were improved with both in 1993. The corn yields responded to the application of fertilizer and lime, but not much to only the lime treatments. The yields differences for corn did not reflect much difference due to incorporation of the original fertilizer and lime applications. The soybean yields, although not significant, were higher for the lime and fertilizer being incorporated than left on the surface. This trend has continued through the years.
Additional study will be necessary to determine if the original placement and
amounts of fertilizer and lime will make greater differences in the results
over time.
This study still has another year to go and the final results may vary a little, but to date the following observations seem to be holding true.
Table 1: 1994 Crop Yield - Nutrient Placement - DeKalb
Table 2: pH Soil Test Change Spring 1990 to Fall 1993
Table 3: P1 Soil Test Change Spring 1990 to Fall 1993
Table 4: K Soil Test Change Spring 1990 to Fall 1994
Table 5: 1991 - 1994 Average Crop Yield - Nutrient Placement - DeKalb
1Agronomist University of IL; Superintendent Northern Illinois Agronomy Research Center.
Lambert, R. J., R. G. Hoeft, and R. H. Teyker. Corn hybrids response to supplemental nitrogen, placement, rates, and forms. 1993 Illinois Fertilizer Conference Proceedings. Jan. 25-27, 1993. Springfield, IL.
Lambert, R. J., R. G. Hoeft, and R. H. Teyker. Corn hybrids response to supplemental nitrogen, placement, rates, forms, and previous crop. 1994 Illinois Fertilizer Conference Proceedings. Jan. 24-26, 1994. Peoria, IL.
Teyker, R. H. 1992. Influence of environment and genotype on response to enhanced ammonium supply by corn. In Proceed. of Symposium. Effects of Enhanced Ammonium Diets on Growth and Yield of Wheat and Corn. Soil Sci. Soc. of Am., Foundation for Agronomy Research, Atlanta, GA.
