Using Dairy Manure with Newly Planted Crops

Glen Arnold, Extension Field Specialist, Manure Nutrient Management, Ohio State University Extension

Coming out of a warm, wet winter most dairy producers have plenty of manure on hand going into spring. Rather than applying manure to fields prior to spring planting, and potentially facing planting delays, a growing trend in the Midwest is surface applying manure using a drag hose overtop newly planted corn or soybeans.

An application of 10,000 to 12,000 gallons per acre of dairy manure to newly planted crops will not hinder germination and can actually provide moisture to encourage emergence of the crop. The only precaution is that the field needs to be firm enough to support the drag hose to avoid scouring piles of dirt and burying the seeds too deep. Spring worked fields that have not been firmed up through rainfall are not good candidates for a drag hose.

For soybeans, the manure application needs to be within a few days of planting and definitely before the soybeans begin to emerge. Once emerged, soybeans can be killed by the application of manure until they reach the V3 stage of growth and can handle the damage from both the manure and the drag hose.

For corn, it is becoming common to make two dairy manure applications spaced a few weeks apart. The first is immediately after the crop is planted and the second application is anytime up to the V4 stage of growth (four leaves with collars).  The smaller the corn, the less damage will be obvious from the tractor tires as the drag hose is pulled across the field.

A five-year drag hose treatment was conducted at the OARDC Northwest Station concluding in 2018 to determine what stand damage and potential yield loss may occur from the V1 to the V5 stages of corn (Table 1). A six-inch diameter drag hose, filled with water, was pulled across each plot twice (going in opposite directions) at corn growth stages V1 through V5.

Table 1. 2014-2018 OARDC drag hose damage corn plot results.

The results of this five-year research study suggest corn could be side-dressed or top-dressed with liquid livestock manure using a drag hose through the growth stage V4 without a yield loss. More than 60% of the corn plants snapped off at the V5 stage. While the snapped off plants regrew, they did not produce reasonable ears of grain.

Leaving manure on the soil surface will not capture as much of the manure nitrogen as incorporating the manure. Be sure to have a manure sample collected during the application process and use the analysis to understand what nutrients were applied.

Dairy manure can also be applied to wheat.  A lone application of 10,000 to 12,000 gallons per acre will not provide enough nitrogen to maximize a grain yield, but the moisture and nutrients will spur crop growth, and this can make for a better wheatlage harvest. Using drop nozzles, some dairy farms make a 2^nd application to the wheat field a few weeks after the 1^st application. The drop nozzles place the manure at the soil surface and keep it off the leaves of the wheat plants.