– Richard Purdin, ANR/CD Educator Adams County
Manure is a valuable resource that should not be overlooked.
Winter is here and the holiday season has arrived. As an extension educator this is a time for reflection on all the work of 2022 and how I can better meet the needs of my clientele in the year ahead. As both an Agriculture extension educator and cattle feeder I have many things that keep me up at night and it’s not all sugar plumbs!
Farmers of all kinds are facing many challenges from rising feed cost, uncertain markets, crazy weather, and incredibly high input cost such as seed and fertilizer. With all these challenges the quest for cutting cost seems endless and most of all challenging. My pencil in the farm office gets shorter and shorter and my wallet gets lighter and lighter. If one of your New Years resolutions for 2023 is to cut input cost and make money, Santa Claus might be delivering it by the ton in a manure spreader rather than a sled!
Livestock producers have learned the many benefits of manure range from improving soil organic matter to providing essential macro-nutrients such as nitrogen, phosphorus and potassium. On the flip side, manure can be a pain to handle. This is why the fields closest to the barn most commonly have the highest nutrient contents.
Farmers have also learned that it takes a lot of manure to get enough essential nutrients to sustain crop growth alone. The Ohio Livestock Manure Management Bulletin 604 tells us one ton of beef manure from a bedded pack contains 7.9 pounds of nitrogen, 4.4 pounds phosphorus, and 6.6 pounds potassium per ton of material.
Another challenge is that much of the nutrient content of manure is in the organic form meaning that it takes time to break down and become available to plants. Nutrients from manure can also be lost through leaching, runoff, and in the case of nitrogen, volatilization and denitrification.
Timing of application is tricky too. Right, wrong, or indifferent I have very fond childhood memories of freezing my face off on the old International 1066 spreading manure in the winter because we didn’t have enough storage space to last until spring. Today with the help of USDA NRCS and Soil and Water Conservation Districts many farms have been able to build manure storage facilities that can hold 6+ months of manure.
No matter if you are spreading black gold or liquid honey there are truly many benefits of manure to your livestock operation, but one common overlooked benefit is the ability of manure to improve soil pH.
I have had a few conversations with producers wondering if manure applications to their field could be making their soil acidic? This has been a concern among many livestock operations especially dairy farms who might be limited on land and overstocked on manure! In most cases manure can actually have a benefit to soil pH levels depending on a few factors including.
- The 4 R’s: The 4 R’s – right rate, right time, right place, right source – are not just applicable to commercial fertilizer and pesticides, but also manure as well. This is an easy way to help remember the benefits of utilizing your manure in the best way without creating an environmental disaster! All factors involved in the 4 R steps can make a big difference on manure value to the crops and long-lasting effects to the soil.
- Animal Diet: This factor might be the most important factor to consider when it comes to the manure’s ability to reduce acidity in the soil. As a CCA I often discuss topics of plant uptake of nutrients and removal from the soil. Calcium soil levels have a great effect on soil PH levels, so one would assume that the more calcium retained in forages and grain consumed and digested by livestock and excreted out in the manure would be returned to the soil. Calcium carbonate is often part of many feeding rations either fed directly in the ration or given in free choice high Ca mineral. Other calcium sources fed to cattle can include calcium carbonate, ground limestone, magnesium limestone, bone meal, calcium sulfate, dical or calcium phosphate and many others. To learn about more calcium sources check out https://agnr.osu.edu/sites/agnr/files/imce/pdfs/Beef/Mineral.pdf . Even if your operation is based on forages, forages such as clovers and alfalfa with have higher levels of calcium. Unfortunately 20-30% is unavailable to the animal. Dry sun cured hay will also have lower levels of calcium due to the curing process.
- Breed and age: Age, stage of growth and breed type will play a key role in how much calcium will actually be in the manure and not absorbed in the body of the animal or lost through milk. For example, manure from a lactating female would likely be lower than the calcium levels from an open or dry brood cow. Calcium requirements for a lactating beef cow equate to 0.31% compared to 0.18% from a dry mature beef cow. In the quest for heavier weaning weights and larger frame sizes, the average cow in the U.S. has grown to roughly 1400 pounds. This means more intake of feed and large skeletal structure to support (don’t get me started on feeding Holstein or Holstein crosses).
- Proof is in the manure: A research study conducted in the early 1990’s by the University of Nebraska-Lincoln suggests beef cattle feedlot manure and composted manure can contain anywhere from 1% to 4% calcium carbonate depending on the feed ration (Eghball Bahman, January 2002 Liming Effects of Beef Cattle Feedlot Manure and Composting Nebraska Beef Cattle Reports.259.)
- Soil Type: Soil texture, drainage and cation exchange capacity (CEC) play a major role in the soil’s buffering capacity. Limestone application made to crop fields will be based on soil buffer pH levels which is calculated based on soil CEC levels. Light textured soils such as sands and loams commonly have lower buffer pH levels. This means that it takes less limestone to neutralize the soil pH. Clay soils or heavy textured soils will have higher CEC levels meaning it has a higher nutrient holding capacity. This is actually a good thing, but it also means more calcium carbonate will be needed to neutralize the soil pH.
In summary manure is a valuable resource on the farm that should not be overlooked especially when margins are as tight as they are. Manure can provide many benefits to the soil but make sure to follow best management practices such as the 4 R’s of nutrient management pared with soil sampling every three years and annual manure testing. This will allow you to get more value out of the manure in the long run. Last but not least, don’t fire your custom limestone spreader yet. Manure has soil pH neutralizing value but not all manure is created equal and not all fields need the extra baggage that goes with it such has high soil test phosphorus or potassium levels.
I wish everyone a prosperous and happy new year and have fun spreading the money in 2023!
Helpful resources:
https://core.ac.uk/download/pdf/17233271.pdf
https://acsess.onlinelibrary.wiley.com/doi/full/10.2136/sssaj2000.643962x
https://agcrops.osu.edu/sites/agcrops/files/imce/fertility/bulletin_604.pdf
https://u.osu.edu/beef/2016/11/09/manure-spreader-calibration/