sealPurdue News

February 3, 2003

Planter maintenance now increases yield potential at harvest

WEST LAFAYETTE, Ind. – As farmers eagerly wait for spring and the ground to thaw, a Purdue University agronomist said there are planter repairs that can be made now to get ready for planting season.

"Farmers should do preventative maintenance on planters to ensure good corn stands this fall," said Bob Nielsen, Purdue Extension corn specialist. "The planter is one of the most important pieces of equipment for producers. Planting mistakes due to equipment malfunctions are permanent, and farmers will have to accept the yield loss that may come with that oversight."

Planter maintenance gives producers a better chance of having uniform stands during the growing season. Inconsistent stands are due to emergence and within-row spacing variability and can reduce a field's potential yield, Nielsen said.

"If the metering unit does not put seed down in the ground uniformly and evenly, there will be uneven germination and emergence," Nielsen said. "Uneven emergence can cause a 10 to 15 percent reduction in yield, while inconsistent germination can cause a 3 to 5 percent yield loss."

From 1987 to 1996, Nielsen measured plant spacing variability in Indiana and Ohio cornfields. During that time 350 fields were sampled, and the standard deviation, or the measure of variation in a group, was figured. The standard deviation of plant spacing was 3 inches or less in about 16 percent of the fields. In 60 percent of the fields spacing was 4 to 5 inches, while 24 percent of the fields had 6 inches or more of spacing variability, Nielsen said.

"Typically farmers want a plant spacing variability of 2 inches," he said. "Two and a half bushels per acre are lost for every one inch increase in the standard deviation of plant spacing.

Even though a field may look uniform from the road, it is important that farmers get out in their fields and measure the actual plant-to-plant spacing. Plant spacing variability is typically related to misadjusted or malfunctioning planter mechanisms," Nielsen said.

Nielsen said farmers should check all moving parts on the planter and replace any pieces that may be worn or broken. Implement dealers typically offer to make these service adjustments; however, farmers also can do the maintenance themselves. Farmers also should check to make sure the planter is thoroughly cleaned and that drive chains are lubricated and in good condition.

Purdue Extension publication, "Stand Establishment Variability in Corn," includes a checklist of planter services and repairs. It is available online.

Farmers also should pay attention to the planter's depth control settings to make sure they are accurate, Nielsen said.

Metering units that monitor fertilizer and insecticide applications should be checked for any inaccuracies. Nielsen said producers could save money if they are applying too many chemicals, or they can improve their efficiency if they are applying too little.

"The time and money a farmer spends on maintenance now is a great investment because of the cost savings and yield potential they can gain this season," Nielsen said.

Writer: Jennifer Doup, (765) 494-8406,

Source: Bob Nielsen, (765) 494-4802,

Ag Communications: (765) 494-2722; Beth Forbes,;

NOTE TO JOURNALISTS: Bob Nielsen is out of the country until the first week of March. Media who have questions for regarding this story can reach him via e-mail at His e-mail access will be limited, but he will return messages as soon as possible.

Related Web site:
Purdue Extension Farming 2003

* To the Purdue News and Photos Page