Illinois Fertilizer
Conference Proceedings
January 27-29, 1992
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Lyle Paul1
As more grain producers change their operations to include reduced or no tillage,
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 this
benefit is greater than any negative effect from the lack of fertilizer and
soil mixing. There has been a concern by others that occasionally, fertilizer
needs to be mixed into the soil to get maximum yields. This study attempts to
answer the question of whether mixing of fertilizer and lime into the soil will
benefit corn and soybean yields.
This study is a randomized complete block design with four replications with corn and soybeans being planted each year in a corn-soybean rotation. The initial treatments were to raise the pH to 6.5, P1 to 50, K to 300, leave them untreated, or use maintenance applications of fertilizer. One-half of the plots were plowed after liming and fertilization and one-half were untilled. In succeeding years all plots will be 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. This field has been in a corn and soybean rotation with minimal fertilizer added.
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 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 and design. 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 field cultivated
once before planting. After planting the only additional disturbance to any
plots was a row cultivation. The entire plot area was row cultivated using a
zero-till cultivator. Plant samples during the summer and grain samples at harvest
were collected from all of the plots. All plots were machine harvested and yield
measurements were taken.
The yield differences in 1991 were due more to tillage operations and their
effects than to fertilizer applications. A confounding factor was the difference
in weed control under the different systems. All plots were treated with herbicides,
but the efficacy of weed control was not the same for all plots.
1Associate Agronomist University of I1.;
Superintendent Northern Illinois Agronomy Research Center.
