Drive through counties in the Corn Belt which have received far too much water and you will still notice differences in the field. Dave Nanda, consultant for Seed Consultants, Inc., believes part of it relates to management practices as much as to the weather.
Corn Illustrated 7/21: Do you need foliar fungicides this year?
Consider this example, concerning three fields farmed by three different people, all fields contiguous to one another.
Field A: Planted first week of May, was nearing tasseling before heavy water hit. The field took on 10 inches of rain in two weeks. Disease and some N deficiency on lower leaves is showing up, but the field still has potential. Put the yield estimate around180 to 200 bushels per acre.
A year ago, fields on this farm yielded well above 200 bushels per acre. It's strictly a guess – yield for this or fields B and C have not been officially estimated. Ears aren't big enough yet to do actual estimates.
Field B: Planted by mid-May, field has some wet soils without good drainage. You might suspect soil compaction issues. Corn isn't as tall as in field A and not as green, but still good to average. Peg yield potential in this field at 140 to 160 bushels per acre.
Field C: Planted after mid-May, this corn was shorter when heavier rains came. Areas within the field have drainage issues. There could be soil compaction issues in this field as well. The field is plagued by the up and down, tall corn, short corn syndrome. It also varies across the field in various spots form dark green to yellow in color. Roots apparently aren't getting to nitrogen in some places.
Corn Illustrated 7/14: The debate is on: Will late nitrogen help?
Put the yield potential today at 100 to 120 bushels per acre. This field needs a great finish with ideal weather to move higher and yield more.
Three fields, three planting dates, different N practices and tillage practices – the end result will likely be differences in yield.