Why Do They Do That? – Crop Scouting

crop scoutLast summer my time was spent walking the corn and soybean fields of Southeast Iowa searching for weeds and pests that did not belong in the field. But why was I needed as a crop scout? Farmers’ livelihoods depend on their crops. Weeds and pests can easily overtake the field if not carefully controlled. It was my responsibility as a crop scout to identify the weeds and other possible concerns in the field and inform the farmer.

So what are crop scouts looking for in the field? First they look for any abnormalities in the plant. When plants are off-colored, chewed, stunted or dead, that could indicate issues that the farmer needs to be aware of. The causes could be soil, pest, or nutrient related, but it is important to determine the cause of the problem so it can be solved quickly.

The purpose of scouting is to give a representative assessment of the entire field. While scouting, it is important to look at multiple areas of the field. It depends on the size of the field for how many samples are taken. The rule of thumb is to check a minimum of five locations in fields of less than 100 acres. In fields greater than 100 acres, a minimum of 10 samples should be taken. Taking random samples is imperative to having a representative assessment of the field. Scouts do not just focus on the entrance, edges, waterways, high, and low areas, but rather randomly select various spots in the field to collect samples and stand counts. 

A crop scout keeps busy early in the season identifying weeds that are in the field. Scouting for weeds before planting seeds allows the farmer to know what weeds are growing in the field, the growth stage of the weeds, and the weed populations. Controlling weeds before they reach four inches tall can help eliminate yield loss. After the weeds have grown over four inches tall, they are harder to control.  Knowing what weeds are in the field allows the farmer to make better management decisions while it is easier to combat the weed issue in the field.

Scouting after the seeds are planting can show farmers seed damage, early pest damage, and many other factors. When plants start emerging, taking stand counts helps the farmer decided if they need to replant. They can also evaluate their management decisions and make changes for next years planting season. When taking a stand count measure 1/1000 of an acre. This measurement can be found by using the table below. Then count the number of plants in the measured area. Take at least six samples throughout the field. Then take the average number of plants and multiply it by 1,000 to calculate the final plant population per acre in the field. Most farmers plant corn at a rate of 29,000 to 38,000 seeds per acre and soybeans at a rate of 130,000 seeds for 21 inch row spacing and 210,000 seeds for 7 inch rows per acre based on 90% germination and 90% emergence rate.

crop row spacing

Crop scouts also keep a watchful eye out for insects. The scout must identify the insects present in the field, what ones are harmful, the amount of insects, and assess the damage caused by the pests. Damage can be seen by observing the foliage, seed heads and pods, stems and roots. By swinging a net over the top of the crop canopy, scouts are able to capture insects in the net and get an accurate estimate of how many insects there are per square meter. Inspecting the top individual leaves for insects can also be done in addition  to using a sweep net. It is important to observe the stem and roots to look for any signs of damage. Punctures on the stem can indicate insect damage. Signs of chewing can be an indication of insect damage even when you do not see any insects at the time of the scout.

Knowing the symptoms of plant diseases, is another important skill for crop scouting. Plant diseases can be caused by weather, fertilizers, nutrient deficiencies, herbicides, and soil problems. Watch this video for a quick rundown of corn diseases from an Iowa State University Field Pathologist.

Farmers want to make sure they know what is occurring in their fields, so they are sure to scout for weeds, pests, and diseases. Next time you drive by a corn or soybean field, take a look to see if there is someone out scouting a field.


P.S. Did you ever spend time walking fields as a crop scout? Tell us about your experience in the comments below.

Why Do They Do That? – Burning Fields and Ditches

This time of year you may see billowing plumes of smoke rising up across Iowa. Menacing blazes are seen by motorists traveling the state roads. Ditches are being burned and in some cases entire fields get burned. But, why?

Seventy-one years of Smokey the Bear have ingrained in us that fires are bad. We see their destructive power when they level a house or destroy a forest. But, throughout history fires have been an essential tool in land management.

042115_Burn_Meier1Each spring farmers and other land managers use controlled burns (also called prescribed burns) to put nutrients back into the soil and revitalize the land. These intentionally set fires serve a valuable purpose. At the end of the growing season plants will leave a lot of dead matter above the ground where it does not easily decompose. Fire breaks down that plant matter and releases the nutrients so they are available to the soil and can help promote future plant growth. These prescribed burns are often applied to road side ditches where dead plant matter can build up quickly.

Fires can also help seed new plants. Many seeds have a thick outer shell that needs to be broken before the seed will start to germinate. Fire can break this shell and then the seed ends up laying in a nutrient rich bed to start growing. Healthy soil is the primary goal of using fire as a tool. Secondary goals of prescribed burn include brush and weed control. Fires can even help control ticks and parasitic worms that might infect livestock that graze on the land.

OLYMPUS DIGITAL CAMERANative Americans also used prescribed burns to manage grasslands long before we started farming in Iowa. Native Americans saw the improved plant growth after a fire and how the animals they hunted gravitated to this new growth. They used fire to manage the grasslands and ensure the herd health of the animals they hunted.

Farmers Take Great Care

stelprdb5294229Prescribed burns or controlled burns are effective because they are controlled. Land managers set fires in the spring when the ground is still wet and there is high humidity. This makes the fire easy to control and direct. It is also important to pick a day with very little wind. Too much wind can make the fire large and uncontrollable.

Land owners doing prescribed burns are careful to never leave them unattended. They carefully monitor the fire in progress. They often work with the local fire department to ensure the fire stays under control. And of course they are sure to obtain the appropriate permissions and permits necessary to do prescribed burns.

grassWhile fire might initially cause ugly, charred pieces of land, it is an important tool to create lush, rich vegetation.

– Will