Iowa State University Extension and Outreach Field Agronomists have completed their spring survey of subsoil moisture in northwest Iowa. Subsoil moisture sampling in Iowa dates to February 1954 when ten sites were chosen for soil moisture sampling. In 1959, the sampling increased to 22 locations, and in 1971, 61 locations were sampled. Today, 18 locations are sampled in northwest Iowa.
The sites were selected for being typical for the major soil type in the area of sampling. Each site that was selected has little or no water run-on and no ponding. A 40-feet-by-40-feet area is designated for sampling at the locations, and GPS helps ensure sampling is done at the same location each spring and fall. Spring 2025 results can be found in the table along with past moisture sample results.
Table 1 compares the results of the last 4 sampling periods from Spring 2025 to Fall 2023
| Location | Spring 2025 | Fall 2024 | Spring 2024 | Fall 2023 |
|---|---|---|---|---|
| Akron | 7.0 | N/A | 9.9 | 6.3 |
| Battle Creek | 9.2 | 7.4 | 8.6 | 4.8 |
| Calumet/Sutherland | 8.4 | 7.9 | 10.6 | 8.1 |
| Castana | 4.7 | 4.2 | 4.1 | 2.7 |
| Doon | 10.3 | 7.2 | 9.3 | 3.6 |
| Estherville | 6.0 | 3.3 | 7.5 | 5.7 |
| Ireton | 9.9 | 7.8 | 10.2 | 5.8 |
| Kanawha | 8.8 | 7.7 | 7.8 | 5.4 |
| Lawton | 9.9 | 3.4 | 8.8 | 5.7 |
| LeMars | 9.0 | 6.2 | 9.9 | 6.3 |
| Marcus South | 9.3 | 5.8 | 8.5 | 7.5 |
| Newell | 8.7 | 5.8 | 9.7 | 5.3 |
| Rolfe | 7.5 | 4.2 | 6.4 | 5.9 |
| Rossie | 9.6 | 7.0 | 9.3 | 9.1 |
| Sanborn | 7.5 | 8.1 | 9.9 | 6.8 |
| Schaller | 8.3 | 3.6 | 8.8 | 6.7 |
| Sibley | 7.3 | 6.6 | 10.2 | 6.3 |
| Spirit Lake | 6.6 | 3.6 | 6.5 | 7.6 |
The values we see in the table align with numbers we expect to see in the spring based off our historical data. Although last spring appeared to be much wetter, the data we collected shows some values slightly above and some slightly below what we saw in 2024. Soil moisture is reported in inches of plant available moisture after calculations account for plant available and plant unavailable moisture. A full profile in northwest Iowa can hold around 10-11 inches of plant available moisture.
Soil moisture is sampled to a depth of five feet in one-foot increments at predetermined locations in the spring and fall. Moisture samples are taken to a depth of 5 feet as corn and soybeans can root to this depth. In years with reduced rainfall, understanding ways to conserve soil moisture is important. Methods of moisture conservation include reducing surface runoff, reducing tillage applications, and increasing ground cover with crop biomass.
The following are the values of plant available moisture for the spring of 2025 with the spring of 2024 values denoted by ().
Between the fall and spring sampling dates, from mid-November 2024 to April 14, 2025, northwest Iowa received around 5-8" of precipitation. This was slightly below normal for the area, but the areas near the Clay and Buena Vista County line did receive almost 2” of precipitation above normal. Windy, dry (low dew point temperature), and warm conditions in March allowed for some evaporation from the soils into the atmosphere. On average, during this time period, temperatures were 1-3 degrees warmer than normal. Locations with the greatest precipitation also were cooler.
April, May, and June are the wettest months in the year in Iowa. Typically, 0.70”-0.95” of precipitation is expected per week at this time. Year to date, we are slightly below normal for precipitation in the northwest climate division region. Current outlooks from the Climate Prediction Center show increased chances for above average precipitation in the next two weeks. For hourly forecast information, go to the National Weather Service and type your ZIP code in the search bar on the top left-hand corner for your location-specific forecast.
In summary, this year’s subsoil moisture results show most locations going into the growing season with average levels of soil moisture. This allows for favorable soil conditions for planting and a head start on moisture needed to raise the crop. A corn or soybean crop needs about 20 inches of moisture to raise a normal crop. Use the Iowa Environmental Mesonet website to keep track of precipitation for your farm.
For more information, contact Leah Ten Napel at 712-541-3493 or Gentry Sorenson at 641-430-6715.
Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Integrated Crop Management News, and Iowa State University Extension and Outreach. If this article is to be used in any other manner, permission from the author is required. This article was originally published on April 21, 2025. The information contained within may not be the most current and accurate depending on when it is accessed.
- Field Agronomist in NW Iowa
- Field Agronomist in NW Iowa
- Weather and Climate Extension Specialist