Condition soils to maximize manure opportunities

6/13/2019
This article was origionally published in Agriview and is part of a four-piece series on creating new manure spreading opportunities for Wisconsin farmers. It was written by Aaron Pape, UW Discovery Farms Tile Drainage Education Coordinator based on UW Discovery Farms work and participating farmer experiences. 
 
Finding the right opportunity to apply manure can be challenging for dairy farmers. Corn silage generally offers spring and fall spreading windows, times that often bring wet and variable weather. Discovery Farms has conducted research illustrating how nutrient losses can be minimized by avoiding manure applications before runoff inducing rains. Even if it is not raining, saturated soil conditions pose additional challenges. Manure applied to saturated soils is at elevated risk of nutrient loss to runoff, and equipment traffic can cause severe soil compaction and rutting.
Not only are farmers dealing with adverse weather conditions, but they may be jockeying to fit into the schedule of a custom manure hauler, while trying to fit other field operations into the same timeframes.  Like most things in farming, when conditions are right for you to spread, they are probably right for all your neighbors too. Fleeting opportunities to get manure pits empty puts stress on both the farmer and custom manure hauler, sometimes resulting in manure being applied in less than ideal conditions. 
Manure’s nutrient value is maximized and  soil compaction and water quality risks are minimized when manure is applied under the right soil and weather conditions.  While we cannot control the weather, we can make management choices that affect our soil conditions.  Management practices have a direct impact on how frequently soils will be in proper condition for manure applications.  Here is how you can condition your soils to be ready for manure  so you can spend less time waiting for fields to dry.
A first step to keeping fields in spreadable condition is to reduce tillage.  Manure applications to soils that are dry and firm will hold manure and carry equipment with less risk of compaction.  Tillage breaks apart soil aggregates and reduces the weight bearing capacity of the soil. Those soil aggregates are what supports equipment and keeps it from sinking into the mire. Recent Discovery Farms soil health project data suggests that reducing tillage can also increase water infiltration.  No-till fields will often carry equipment earlier after rain and earlier in spring than tilled fields.
Similarly, having growing plants in the field year round can improve field access.  Living plant roots bind soil together, feed soil organisms that secrete glues to build soil aggregates, and act as a web which helps carry the weight of equipment.  Growing plants remove water from the soil through transpiration as plants pump water up through their roots and out the leaves, creating better conditions to drive and spread manure on.  Alfalfa fields provide a great example of this drying effect. You can walk in a hay field in spring without getting mud on your boots long before a bare field is dry and firm. Matt Van Wychen, a Discovery Farms participant in Northeast Wisconsin, notes the improvement in weight bearing capacity of their cover cropped fields. He can get into fields without damaging the soil while his conventional farming neighbors are making ruts. Living plants can speed soil drying and improve field access. 
Prioritizing cover crop planting to maximize growth will help get soils into spreadable condition.  Cover crops also help reduce erosion and actively retain nutrients from manure applications.  “Spreading green” on living plants may reduce nutrient losses and maximize your returns from that investment in applied manure nutrients.  Fields managed under reduced tillage and cover crops will support not only manure equipment, but all types of equipment, from planting to harvest.  This provides the flexibility to fit manure into times where soil conditions may not have previously allowed.
As weather becomes more volatile, water quality issues remain critical and fitting manure hauling into the rest of the farm management continues to be a challenge, farmers must find ways to maximize manure spreading opportunities. Discovery Farms continues to research the impact of management practices on water quality and soil conditions. Our soil health project is working to empirically validate these concepts that many farmers are already experiencing on their own operations. Conditioning soils through reduced tillage and living plants like cover crops can increase the number of days that soils can support equipment and are fit to take manure.  Work to keep soils in spreadable condition to help carry manure, and your stress, away.