Farmers should delay spring manure applications
April 14, 2014 by Jerry May and Shelby Bollwhan Michigan State University Extension
April 14, 2014, East Lansing, MI – I once hired a retired contractor to help me with a large project. As we worked together I learned he had many inappropriate sayings but once in a while he would present one worth remembering. “Take your time, you’ll get more done,” was one of his more useful sayings.
We have all seen it. Soil conditions weren’t quite right when the neighbor farmer started working in the spring then all summer long the tire tracks of the tillage tractor can be picked out angling across the field as the crop growing over the tracks is stunted and behind the rest of the field. Those compacted tracks will also show up at harvest in reduced yield and in subsequent years as the farmer tries to rebuild the field’s soil structure.
Spring 2014 is having a hard time coming. We are well into April but fields are still saturated and snow banks still exist in many places. Spring fieldwork is being put on hold while everyone is hoping better weather will be just around the corner. Once fields begin to firm up and dry out, long hours will be put in trying to make up for lost time.
Spring manure application is one of the most challenging farming practices. Large tractors pulling heavy manure spreaders across soft fields, if rushed, will lead to compacted soils and reduced yields. The negative impacts of soil compaction are well documented and are accepted throughout production agriculture. But given today’s large equipment, is it possible to spring apply manure without the negative consequences of soil compaction? Research from the University of Wisconsin encourages allowing soils to dry out before starting spring manure applications.
Using eight different sites across four Wisconsin counties, researcher Greg Sanford and his team tested the impact of manure application made under acceptable field conditions. Each site consisted of three treatments: manure, farmer check and compaction only. Manure was applied using either tractor drawn tankers (4,600 and 5,700 gallons) or a truck-mounted tank (4,000 gallons) with maximum axel weights ranging from 19,880 to 30,955 pounds. The farmer check and compaction only treatments received commercial fertilizer to meet crop nutrient needs. Manure was applied at 12,000 gallons per acre and additional nitrogen supplied based on the results of pre side-dress nitrate tests. The compaction only treatment consisted of driving across the plot with the loaded manure spreader the same number of trips as was required for the manure application at that site. Sanford and his team reported no yield differences between the three treatments and concluded that when applying manure on relative dry soils, compaction from manure spreaders does not significantly impact yields.
My contractor’s clever remark is particularly applicable this spring. Being patient this spring by allowing fields to dry out prior to starting manure applications will be rewarded in the fall with higher yields and improved soil structure.
Last December’s early onset of winter weather combined with heavy snow cover and a late spring may mean some manure storages are nearing full. Farmers faced with limited additional manure storage capacity may find two previously posted Michigan State University Extension news articles worth reviewing. Both “Avert and prevent manure storage spills during this rainy season” and “Manure structures should be monitored during extreme wet weather conditions” contain helpful suggestions on managing near full manure storages under unfavorable conditions.