Army cutworms have been found in some wheat and alfalfa fields. I honestly haven’t looked at pastures but have gotten several calls about pastures this week, so perhaps be looking at them as well. The threshold is four or more cutworm larvae per square foot of winter wheat or alfalfa. A lower threshold is necessary for stands that are new or had some winterkill/drought-stressed. Damage looks like chewing on the leaves stems to complete stand reduction. Army cutworm larvae are greenish-brown to greenish-grey caterpillars, approximately ½ to two inches in length. They feed at night so you may have to look under residue or dirt clods to see them in the day.

Nitrogen Fertilizer Trends in Nebraska from 1955-2023: Dr.’s Richard Ferguson, Bijesh Maharjan, and Javed Iqbal wrote a nice updated article on nitrogen fertilizer trends for CropWatch this week. I pulled out a few excepts here, but please also check out the full article with the graphs and figures here: https://go.unl.edu/ki69.

“As farmers embark on another growing season in Nebraska, most will be applying some form of nitrogen fertilizer to optimize crop production. …  Initially, ammonium nitrate, mostly sold in bags, and anhydrous ammonia were the dominant fertilizer sources. Nitrogen fertilizer use grew steadily from 1955 into the 1970s as fertilizers became more available and farmers saw the benefit for crop production. During this period, urea and urea ammonium nitrate solutions became more available and their use grew. Anhydrous ammonia dominated fertilizer sales during this period, peaking in 1968 with over 75% of total N sold as anhydrous ammonia.

Use of urea ammonium nitrate (UAN) solution (both 28% and 32% N) began to take off in the 1980s, and today is the most dominant form of nitrogen fertilizer used in Nebraska. In 2022, 57% of all N consumed in Nebraska came from UAN solutions, while 23% came from anhydrous ammonia, and about 14% from urea.

Total nitrogen used in Nebraska began to plateau around 1980 until about 2010. Since then, trends for increasing total N use have been observed. This trend generally coincides with an increase in land area from which corn is harvested. Approximately 8.85 million acres of corn were harvested in Nebraska in 2010, while 9.5 million acres of corn were harvested in 2023.

Figure 4 shows a very positive overall trend, with fertilizer N use of around 1.6 to 1.7 pounds fertilizer N per bushel of corn in 1965, to around 0.8- to 0.9-pound fertilizer N per bushel of corn in 2022. This positive trend illustrates that Nebraska farmers have become much more efficient through the years in managing nitrogen fertilizer.

There are many factors influencing this trend, including genetics advances and overall improvement in production practices. However, it’s likely that a major factor in this trend has been growing awareness of the risk of environmental degradation from excessive nitrogen application, influenced by many educational programs conducted by the University of Nebraska-Lincoln and natural resources districts. This trend is also influenced by requirements in some groundwater management areas for producers to follow nitrogen and irrigation best management practices.

While the general trend for the past 60 years is positive, Figure 4 also shows very little change recently in fertilizer nitrogen use efficiency: it has remained around 0.8- to 0.9-pound fertilizer N/bu since 2000 (circled data points). This data also does not illustrate variations in efficiency that occur in regions across the state. This lack of recent improvement suggests that current widely used practices may have reached their limit in terms of nitrogen use efficiency, and adoption of other tools, such as in-season application and sensor-based fertigation, may be required to further increase nitrogen use efficiency.”

I took a picture of this so here is a clickable link to register for the webinars: https://go.unl.edu/annualforagewebinar