Extension Update by Jenny Rees

Cold Weather and Livestock: This week I found gratitude time and again for a warm home. Thinking of those who haven’t been as fortunate. Have also thought about our livestock producers taking care of animals. In the unfortunate event of livestock losses, please document/take photos in the event of any disaster declarations for livestock indemnity payments (LIP).

Crop/Livestock Systems On-Farm Research Study: At last week’s cover crop and soil health conference, Ken Herz shared on his family’s on-farm research study. I’m so proud of and grateful to the entire Herz family for their partnership in this study and for the focus on the economics of an entire system! This study was designed with a system’s perspective incorporating crops, cattle, cover crops in a way that fit many operations in a non-irrigated setting. Their goals were to increase soil organic matter and ultimately determine yield and economics of the entire system. The crop rotation is Wheat (with cover crop planted into stubble after harvest), Corn, Soybean. Cattle graze the cover crop in the winter and also graze the corn residue. No-till wheat prior to corn for increased moisture saving and yield is common in this part of the State as is planting a cover crop into wheat stubble for grazing. The questions I hear include:

1-What moisture and potential yield am I giving up to the successive corn crop if I plant a cover crop into my wheat stubble?
2-If there’s a yield loss in the successive corn crop, do the economics of grazing the cover crop offset that loss?

We had three treatments and two locations (Location 1 had a cool-season cover crop and Location 2 had a warm-season one). The treatments are: ungrazed wheat stubble, ungrazed cover crop, and grazed cover crop. We’ve collected soil property, moisture, nutrient, and health data; yield and moisture of each crop; cover crop biomass; grazing days; and economics.

Location 1 in Nuckolls county began in 2016 with a cool season cover crop planted after wheat was harvested and manure applied. Three-year analysis showed no difference in soil physical properties (bulk density and compaction) amongst treatments. There was greater total microbial and fungal biomass in the grazed cover crop treatment (indicators of improved soil health). Interestingly, the ungrazed wheat stubble is the most economical treatment at this location. Reasons: cost of hauling water for grazing, numerically higher yields in the ungrazed wheat stubble, variable biomass in cool season cover, and a large yield hit to the 2018 soybeans in the grazed cover crop treatment during a dry year. In 2018, to the line there was a stress difference in the soybeans and that treatment read drier via soil moisture sensors. They’ve been conservative with grazing so at the time we couldn’t explain it. In taking soil health tests in year 3, we realized how greatly the microbial biomass had increased where cattle grazed. Our hypothesis is microbes broke down the remaining residue exposing soil to more evaporative losses resulting in less soil moisture and less yield for soybeans in the grazed treatment during a dry year. It’s now on our radar when grazing occurs to get cattle off even sooner to account for feeding the microbes too.

Location 2 in Webster county began in 2018 with a warm season cover crop. Over 4 tons of biomass allowing for 91 grazing days, not hauling water, and no successive crop yield differences all led to the grazed cover crop being the most economical treatment at this location.

Take home points: it’s important to add all the components when looking at economics. Grazed cover crop treatment at Location 1 would look better if we didn’t include the large cost of hauling water and if there was more cool season biomass allowing for more grazing days. The differing results at the two locations showed the influence of cover crop biomass and importance of including value of grazing; fencing/water/labor costs for livestock; cover crop costs; and successive crop yields in system economics. It’s easy to make assumptions that a certain practice is profitable! Location 1 will hopefully continue another 6 years switching the cool season cover crop to a warm season one to compare economics on the same field. We’re curious if the warm season cover will increase biomass and grazing days enough to outweigh the water hauling costs and show a benefit to the grazed cover crop treatment, or if the ungrazed wheat stubble will remain the most economical for this field location.

Regarding cover crop economics, it could be helpful to determine a consistent way for assessing a dollar value for potential benefits such as aiding in weed and erosion control, nutrient uptake, etc. This may aid conversations with landlords and lenders for those desirous to try them. Without livestock value, currently on paper, there’s really only costs.