In 2006, an On-Farm Manure Management Demonstration to Protect Impaired Waters 319 Grant site was established in Fillmore County. One of the requirements of this demonstration is finding a site with out alfalfa in the rotation for five years and without manure for three years.
Very few livestock farmers have land without manure history. Fortunately, Craig Mensink agreed to be the cooperator using land rented from Bob Boice, swine manure was borrowed from Bruce Dornink. We had exactly the same scenario in 2005 with a dairy manure demonstration near St Charles.
Bruce had very rich swine finishing manure which tested 76-36-50, for nitrogen, phosphorous, potash, respectively. Typical swine finishing manure is 53-39-29 for N, P, and K. So this was a very good source of nitrogen and other nutrients.
Interest in the use of livestock manure for supplying crop nutrients and has significantly increased in recent years, This interest is driven both by increased commercial fertilizer prices and the fact that both research and producer observation suggest that manure can provide a crop yield boost.
I have bolded what I consider the most interesting results in the chart below with the demonstration yields:
Manure Fertilizer Yield
N Rate Rate bu/acre
0 80 200.5
0 120 197.4
0 160 204.1
182 0 226.4
182 40 237.2
182 80 230.1
182 120 214.6
Without any additional nitrogen either through commercial fertilizer or swine manure the yield was 163 bu/acre. With 80, 120, or 160 lbs. of fertilizer supplied nitrogen the yield jumped to 200 bu/acre. With the switch to nitrogen provided by swine manure yield increased to 226 bu/acre. Also, you will want to note with the most extreme quantities of nitrogen fertilizer the yields fell to 214 bu/acre.
We normally expect a 8-10 bu/acre increased corn yield and 2 bu/acre of increased soybean yield on land with a manure history. With the 26 bu/acre increase, I considered the possibility that there was also an potash affect taking place, but potash was applied in the fall of 2005.
At a meeting in December, Gyles Randall, Soil Scientist, SROC, Waseca, reported a field with a ten year manure history from 1994-2003 and no manure since had a 31 bu/acre yield advantage. The fertilizer program was the same with the only variable being the manure history.
So where am I going with this concern for manure history? The bottom line is a Win/Win situation for crop farmers and livestock farmers. The livestock manure may be worth considerable more to a crop farmer for application on fields with no manure history, particularly from a livestock farmer that has been building his phosphorous levels through the years. There could be both economic and environmental benefits to both.
Determining the economic value of the nutrients in livestock manure can be tricky because there are a lot of variables with manure. In any situation the needs of the crop, manure nutrient concentration, manure nutrient ratio, incorporation techniques, field fertility levels and manure history, and ability to apply accurately will impact manure value. Farmers need to consider their own situation when making manure value decisions.
In recent years Bob Koehler, Extension Educator at the Southwest Research & Outreach Center, and Bill Lazarus, Farm Management Specialist at the University of Minnesota, have develop a spreadsheet to analyze individual manure value situations and to develop some thumb rules to use in putting a dollar value on manure.
Koehler will be involved in a Manure Value Workshop to address those issues on March 14, 10:00 am - noon, Fillmore County Office Building, in Preston. I will providing additional details in a few weeks.