Illinois
Fertilizer Conference Proceedings
January 27-29, 1997
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K.B. Ritchie, R.G. Hoeft and E.D. Nafziger
We conducted small-plot starter fertilizer studies at 4 locations from 1993-95. Some of the starter fertilizers we tested were consistently profitable in our studies. Unfortunately, our location at Pana (Christian county) was flooded 2 of 3 years, and so we do not have complete results on the effect of starter fertilizers on no-till corn in central Illinois. The purpose of these large-plot on-farm studies was to check the yield benefits from starter in a sample of notill farmers, with an emphasis on central Illinois.
Experiments were conducted by cooperating farmers using their own starter fertilizer blends and equipment. Many of the cooperating farmers have used starter fertilizer for about 4-6 years, and have chosen their starter combination and rate based on field tests and advice from their agronomic service providers. Experiments were laid out in a randomized fashion. Because the same starter treatments are not replicated from farm to farm, this study can not determine the effectiveness of any particular nutrient or starter combination.
Originally, about 20 farmers agreed to participate in the study. However, due to excessively wet spring weather, some locations were abandoned completely, and others had reduced plant populations. Other locations suffered herbicide or insect damage that confounded results. We plan to continue these studies in 1997.
Yield increases at the sites that did not have other complicating factors ranged from 3.6 to 8.6 bushels per acre. The grain moisture was a percentage point lower in the starter plots when corn was harvested in the 20-25 % moisture range, and 2-3 points lower when the grain was around 30% moisture.
This paper also contains a template for randomization of side by side strip
trials, and simple calculations of statistical significance for experiments
with 4, 6, or 8 replications comparing two variables (ex: starter vs. no starter,
hybrid A vs. hybrid B).
Table 2: Site characteristics and cultural practices
Form 1: Statistical Analysis of Side by Side Comparisons
Table 3: Two examples of t-test calculations for an experiment with 6 replications
Table 4: Randomization schemes for comparisons of two treatments
1K.B. Ritchie is a Jonathan Baldwin Turner Fellow, R. G. Hoeft and E. D. Nafziger are Professors in the Dept. of Crop Sciences, University of Illinois.
