Farm Talk

Crops

June 2, 2010

Consider all options before replanting

by Julie Abendroth CNHI

Parson, Kansas — As of the May 23rd USDA Crop Progress and Condition Report, corn planting was 86 percent complete while soybean planting averaged 22 percent complete for Missouri. 72 percent of the corn planted had emerged by the May 23rd report date. In west central Missouri specifically, 87 percent of corn and only eight percent of soybean acreage had been planted. 48 percent of the emerged corn crop is currently listed as very poor to fair while 49 percent is rated good and only three percent as excellent. Many corn acres will need to be replanted, due to the saturated soil conditions west central Missouri experienced during the month of May.

As growers try to decide whether to replant to corn or convert fields to soybean production, there are several factors to consider. It is first important to assess the current corn stand and determine the remaining plant population. While a lower-than-desired plant population is not ideal, it may likely yield higher than if the field was replanted to corn. For example, University of Missouri research has shown that a plant population of 20,000 plants per acre will achieve 88 percent yield potential in normal yield environments. If the grower chooses to replant the field on June 5th however, research data indicates that he could expect to achieve 75 percent yield potential. In many instances, if an adequate stand is present, it is wiser to not replant due to the yield loss associated with late planting dates.

It is important to recognize that yield loss due to late planting dates also occurs with soybean. Averaged across 12 experiments, University of Missouri research indicates an approximate 12 percent yield loss associated with a June 5th planting date. However, research has shown that if adequate rains are received during late August and early September, late planting dates can actually out-yield early planting dates. Generally, lower yields are expected with later planting dates because of the effect later planting dates have on the number of nodes produced.  University of Nebraska-Lincoln researchers have found that after the V1 growth stage, a soybean plant will produce a new node every 3.8 days. The ability of a plant to produce nodes is important, because it is from nodes that flowers and eventually pods are set. With later planting dates, fewer nodes are produced and as a result, lower yields typically occur.

If you would like to receive e-mail updates of local crop conditions and pest alerts, contact Julie Abendroth, MU Extension agronomy specialist, at abendrothj@missouri.edu or 816-776-6961.

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