University of Nebraska Extension - Holt/Boyd News Column for the Week of June 23, 2024

LaDonna Werth, Extension Educator Phone: 402-336-2760 E-mail: LWerth2@unl.edu

A Summer-Time Favorite - Watermelon

Watermelon is an American summertime favorite. Throughout the summer months, many cannot get enough of this sweet treat. There are more than 1,200 different varieties of watermelons. Watermelon provides a refreshing way to help us reach the MyPlate recommendation of 1-2 cups from the fruit group each day. One cup of watermelon is equal to 1 small slice (1 inch thick) or 1 cup diced. Watermelon is naturally low in fat, sodium and has no cholesterol. It provides a source of potassium, vitamin C, Vitamin A and folic acid. Some interesting facts about watermelon:

• A watermelon is 100% usable and compostable (70% flesh and 30% rind).
• Watermelon live up to their name as they are 92% water.
• The rind of a watermelon is edible and can be used in stir-fries or salads.
• Hollow out the watermelon to make a compostable bowl for your delicious treat such as a fruit salad or fruity dessert.

Selecting the perfect watermelon - Choose a firm, symmetrical, fruit that is free of cracks, bruises, soft spots or mold. A ripe watermelon will have a dull sheen, dried stem, and a buttery yellow underside where it has touched the ground. Thump your watermelon, as it should sound dull and hollow. Lift them as well, they should be heavy for their size.

Storing your watermelon - An uncut watermelon can be kept for up to 2 weeks at room temperature. When ready to use, scrub with a clean vegetable brush under running water. Dry with a clean towel or paper towel. Once cut, store watermelon in a covered container in the refrigerator for up to 3 days without a decrease in flavor or texture.

Pair your fresh watermelon in new and different ways:

• Watermelon + Feta Cheese + Mint
• Watermelon + Honey + Pistachios
• Watermelon + Lime Juice + Chili Powder

Combine all ingredients in a multi-cooker, seal and cook on high for 10 minutes. Quick release when done, remove lid. Let cool before transferring to a food processor/blender and blend until smooth. Cool and store in refrigerator between uses.

Nutritional Value: 89 calories, 4g Fat, 11g Sugar, Carbohydrates 14g, 1g Protein, 428mg Sodium, 318mg Potassium, 1g Fiber, 26mg Calcium, 8mg Vitamin c, 439IU Vitamin A

Source:Brenda Aufdenkamp – Extension Educator; Healthy Family Project (UNL For Families – June 17, 2024)

How to Determine the Chemigation Injection Pump Setting for a Center Pivot with the End Gun Off and On

Appling nitrogen fertilizer or crop protection products through a center pivot is an efficient and effective method. In fact, it is a well-documented best management practice to apply nitrogen fertilizer as close to the time the corn will use it to get the most efficient use of the fertilizer. Most of the products are injected into the pivot with a fixed rate injection pump. So, how does one figure the pumping rate to set the pump at, and what about the change the end gun causes when it's turned on and off? We will discuss both challenges in this article.

The key to knowing the correct setting for the chemigation pump is to determine how many acres per hour the pivot will cover at the desired irrigation application depth or rate. Chemigation injection pumps are calibrated in gallons per hour (gph). So, if you know how much product you want to apply per acre - e.g., 10 gallons/acre - and how many acres the pivot will irrigate per hour - e.g., five acres/hour - then you will know how many gallons per hour the pump will need to deliver.

For example:

10 gallons/acre x 5 acre/hr = 50 gph

The calculation is just this simple, but it takes some effort to determine the acres per hour the pivot will irrigate.

Different methods can be used to determine how many gallons/hour (gph) the chemigation injection pump should be set to inject. We are going to talk about two of them today.

1. The first one is using the “speed chart” (water application depth per pass chart) in the “sprinkler chart” for the pivot or looking up circle time on the computer panel or the pivot app.
2. The second one involves calculating the chemical injection rate using a spreadsheet. This method gives you more details about the system and is still easy to figure. You will just need to enter the basic information for the pivot. If you are interested, download the spreadsheet (https://cropwatch.unl.edu/2023-CW-News/Chemigation-Calculator-Spreadsheet-01092023.xlsx) from UNL Water.

Both methods require the basic information for the pivot. All the needed details can be found on the sprinkler chart for the center pivot. The sprinkler chart is the documentation that came with the sprinkler package for the pivot and describes the basic layout of the pivot, water flow rate, pressure, size of each sprinkler, etc. If the current sprinklers on the pivot came with the machine when it was new, the pivot dealer should be able to provide a copy. Otherwise, ask the company that sold the current sprinkler package for it. If you do not have the sprinkler chart, then you will need to determine the needed data by measuring the pivot.

Determining the Chemigation Pump Setting Using the Sprinkler Chart

The chemigation injection pump setting can be easily determined using the sprinkler chart. The method is very simple to use if one has the chart, or at least the speed chart part of it. The information can also be gained from looking at the readout on a computer-style pivot panel or the pivot control app.

Let’s take a look at an example. We want to apply 0.30 inches of water with the pivot during the chemigation application.

So, by looking on the speed chart, it will take 21.39 hours to complete the circle applying 0.29 inches (which is the closest line on the chart to the desired 0.30 inches).

If we know the acres under the pivot - e.g., 121.9 acres - we can determine the acres per hour.

Example:

121.9 acres / 21.39 hr = 5.7 acre/hr

Note - The acres listed on the sprinkler chart assume the end gun (if equipped) is on the entire field. Thus, use the irrigated acres from another source if the machine is equipped with an end gun.

So, if we want to apply 8.5 gallons/acre of 32% UAN (30 lbs/acre N) with a pivot irrigating 5.7 acres/hour, the pump would need to be set to pump 48.5 gph.

Example:

8.5 g/acre x 5.7 acre/hr = 48.5 gph

The pump would need to be set to deliver 48.5 gph to apply the planned 30 lbs/acre.

OK, That is Great, But I Want to Use My End Gun

The best answer may be to just not use the end gun because of its lower uniformity and the fact that it will lower the nitrogen application rate when it comes on. However, two methods of solving this problem come to mind. The first is to purchase a variable rate injection pump and the second is, if the pivot is equipped with a computer panel, keep using the lower cost fixed rate injection pump and simply slow the pivot down when the end gun turns on.

The two different speeds can be achieved by a simple setup in the computer pivot panel. The degree of rotation at which the end gun turns on, the program simply slows the speed down and then returns it to the faster speed at the time the end gun turns off. The idea is that we want the pivot to cover a constant number of acres per hour. The key is to know how to calculate the slower speed.

The method uses a ratio of the length of the center pivot vs. the throw of the end gun. The designed end gun throw and the length of the pivot can be found on the sprinkler chart.

Let’s look at an example. If we have a pivot that is 1,300 feet long with an end gun having a throw of 100 feet, how much slower should the pivot travel when the end gun is operating to cover the same acres per hour as when the end gun is off?

First, we need to figure the ratio of the end gun throw (Rg) to the pivot length (R).

Ratio of the end gun throw to the center pivot length:

100ft / 1,300ft = 0.0769

Rounded to = 0.08

Referring to the ratio of Rg/R table found at water.unl.edu it relates to the pivot speed with the end gun on (Se) compared to the speed with the end gun off (S). Therefore, rounding to 0.08, we can look in Table to find our speed ratio of 0.86.

Using the ratio, multiply the pivot speed by the number in the table to get the speed when the end gun is on. So, for example, if the pivot is set to operate at a 90% timer setting when the end gun is off, it should only operate at 0.86 of that speed when the end gun is on.

Calculate the speed when the end gun is on:

90% x 0.86 = 77.4%

Thus, the pivot should operate at a 90% timer setting when the end gun is off and slow to 77.4% when it is on to apply the 30 lbs/acre nitrogen both when the end gun is off, as well as when it is on. The water application will be different - 0.29 inches when the end gun is off and about 0.33 inches when it is on - but the nitrogen rate will remain the same with the constant injection rate pump. The concept behind this method is that the pivot will irrigate the same number of acres per hour, thus the lower cost fixed-rate injection pump will work correctly.

Source:Steve Melvin - Extension Educator Irrigated Cropping Systems (CropWatch – June 18, 2024)

Summer Blooming Perennials

Many perennial plants bloom in the heat of summer.  Daylilies (Hemerocallis) and hosta (Hosta) are well-known staples in the garden and are often in bloom in July and August, regardless of the heat of summer.  Other perennials like big betony (Stachys), blackberry lily (Iris domestica), Joe-pye-weed (Eutrochium), and rattlesnake master (Eryngium yuccifolium) are lesser-known species but equally as beautiful in bloom.

Some flowers like coneflower (Echinacea), Shasta daisy (Leucanthemum), Spike speedwell (Veronica), Queen-of-the-prairie (Filipendula), and yarrow (Achillea) started to bloom in June and often continue into the summer months.  While other species were tardy in spring but still manage to be in bloom by July.  Hardy hibiscus (Hibiscus), milkweed (Asclepias), Balloon flower (Platycodon), and Whirling butterflies (Gaura) sometimes wait to emerge until late May, but they are reliable July and August bloomers.

Summer Bloomers with Long Blooming Periods

Several perennials are known for their long-blooming times in the summer.  Blanket flower (Gaillardia), threadleaf coreopsis (Coreopsis verticillata), false sunflower (Heliopsis helianthoides) and ornamental onion (Allium hybrids ‘Millenium’ or ‘Serendipity’) are often in bloom for two months or more during the summer months.

Summer Blooming Natives

There are many wonderful prairie plants (native to the Midwest) that are showing off in July and August.  Many species of Phlox (Phlox), Blazing star (Liatris), wild quinine (Parthenium), ironweed (Vernonia), and Grey-headed coneflower (Ratibida) are just a few of the many options in prairie plants for mid-summer flowers.

Summer Bloomers for the Shade

Most of the perennials mentioned above bloom best in sunny sites.  Yet, several species perform well in shady locations.  Cardinal flower (Lobelia), corydalis (Pseduofumaria), anemone (Anemone), snakeroot (Actea), and leopard plant (Ligularia) bloom with the hosta in mid to late summer. 

Source: Cynthia Haynes – Consumer Horticulture Extension, Iowa State University (Yard and Garden – May 2024)

Start Monitoring Grasshopper Numbers Now for Most Effective Control

Weather conditions in several areas of Nebraska in the past few years have been favorable to create grasshopper outbreaks. The fall grasshopper survey is a good indicator or possible grasshopper issues the following summer. The 2023 fall survey identified 15 counties in Nebraska with adult grasshopper numbers averaging over 15 per yard, which suggests grasshoppers may be a problem this summer.

Pasture grasshopper species that are most damaging are found in areas with less than 30 inches of annual rainfall. Western two-thirds of Nebraska falls into this rainfall category. With the occurrence of consecutive years of drought grasshopper outbreaks are possible. The past several years southwestern, southcentral, and western Nebraska has experienced below normal precipitation. This type of weather pattern can play a large role in rangeland grasshopper outbreaks.

Approximately 50 species of grasshoppers are found on rangeland in Nebraska, though generally fewer than 10 species ever reach economic levels, accounting for 95% of the damage. Grasshoppers defoliate grass by direct feeding on leaf and stem tissue and by cutting off leaves or stems.

Grasshopper Life Cycle

The developmental stages of all grasshoppers include the egg, nymphal, and adult stages. Most species winter as eggs. Normally, grasshopper eggs will remain in the overwintering stage until the ground temperature reaches 50° to 55° Fahrenheit. Newly hatched grasshoppers look like miniature adults except they lack wings, and their sex organs are not developed. As young grasshoppers grow they shed their skin (molt). Depending upon the species they might molt four to six times, with five molts being the average. The rate at which nymphs develop is influenced by temperature and food quality. Most species reach the adult stage, 30 to 50 days after hatching.

Grasshopper Impact

Grasshoppers consume up to 50% of their body weight every day in forage. A rate of just 2.7 grasshoppers per square yard equals 12,971 grasshoppers per acre.

An acre with 69.7 grasshoppers per square yard equates to the consumption of forage by one cow per day.

Economic thresholds for grasshopper densities in rangeland vary from 8 to 40 grasshoppers per square yard. The thresholds are influenced by several factors, including the cost of control product, projected forage yield, and the value of forage considered for treatment.

Grasshopper Monitoring

One of the better methods for determining grasshopper density is to count the number of grasshoppers using the square foot method. With this method sample at multiple sites about 50 to 75 feet apart. Select a point several feet away and visualize a one-foot square area around the point. Walk toward the point counting any grasshoppers you see in or jumping out of this area. Repeat 18 times, total the number of grasshoppers, and divide by 2; the resulting number will be the number of grasshoppers per square yard.

A request for technical assistance to evaluate the need for grasshopper control in rangeland may be submitted to USDA-APHIS, by contacting David Nielsen at (402) 434-2348 or by email at David.Nielsen@usda.gov

Grasshopper Control

A grasshopper integrated pest management program called Reduced Agent and Area Treatment (RAATs) was developed by researchers at the University of Wyoming to improve grasshopper control in pastures and rangeland. Insecticides are applied in alternating strips, reducing application costs by 50 to 60% and reducing the amount of insecticide used by 65 to 70% compared to conventional broadcast treatments. The RAATs system provides up to 85% control depending upon the rate of growth of the forage, the size of the grasshoppers and coverage obtained.

Two insecticides can be used with the RAATs application method: Dimilin® 2L, and Prevathon®. Dimilin®2L works by interfering with the molting process of grasshoppers and Prevathon® works by contact/ingestion. Both insecticides should be applied when most of the grasshopper population is second or third instar nymphs or when the grasshoppers average ¾-inch long.

For other grasshopper control product options, please contact your local UNL Extension Office. Before using any pesticide, please read and follow label instructions.

Source: Dave Boxler - Nebraska Extension Educator (BeefWatch – June 13, 2024