Iowa State University Extension and Outreach Field Agronomists have completed their fall survey of subsoil moisture in northwest Iowa. Subsoil moisture sampling in Iowa dates back 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. 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.
| LOCATION | Fall ’25 | Spring ’25 | Fall ’24 | Spring ’24 | Fall ’23 |
| Akron | 5.41 | 6.98 | N/A | 9.86 | 6.26 |
| Battle Creek | 6.02 | 9.2 | 7.37 | 8.56 | 4.79 |
| Calumet/Sutherland | 8.84 | 8.36 | 7.88 | 10.61 | 8.11 |
| Castana | 2.80 | 4.7 | 4.18 | 4.13 | 2.65 |
| Rossie | 8.60 | 9.64 | 7.03 | 9.34 | 9.10 |
| Doon | 7.53 | 10.25 | 7.22 | 9.25 | 3.55 |
| Estherville | 5.88 | 5.96 | 3.28 | 7.51 | 5.70 |
| Ireton | 9.62 | 9.88 | 7.82 | 10.2 | 5.80 |
| Kanawha | 10.00 | 8.75 | 7.68 | 7.79 | 5.40 |
| Lawton | 6.82 | 9.87 | 3.44 | 8.83 | 5.68 |
| LeMars | 6.90 | 8.98 | 6.21 | 9.88 | 6.28 |
| Marcus South | 6.18 | 9.31 | 5.76 | 8.48 | 7.49 |
| Newell | 3.62 | 8.74 | 5.81 | 9.69 | 5.28 |
| Rolfe | 4.98 | 7.49 | 4.17 | 6.36 | 5.88 |
| Sanborn | 8.51 | 7.52 | 8.10 | 9.86 | 6.75 |
| Schaller | 8.50 | 8.30 | 3.62 | 8.81 | 6.70 |
| Sibley | 9.31 | 7.3 | 6.60 | 10.2 | 6.31 |
| Spirit Lake | 7.48 | 6.63 | 3.57 | 6.45 | 7.55 |
The table shows that there was some recharge of soil moisture this fall after late October and early November rains. 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 about 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 fall of 2025 with the fall of 2024 values denoted by ().
2025 Drought Monitor
This fall, between October 1 to November 11, northwest Iowa received around 1.5-3 inches of rain. This is around 1-2 inches below normal for northwest Iowa during the fall. The eastern edge of the northwest region received the greatest amounts of rain so far this fall, and that is reflected in the large plant available moisture observation for Hancock County. Since the start of the growing season, most of northwest Iowa received 1-5 inches of rain greater than normal, and would normally receive around 22-25 inches of rain.
Despite overall wetness during the growing season, fall precipitation totals have been slightly below normal, resulting in some areas of abnormal dryness and moderate drought in northwest Iowa. Compared to this same time last year, there are fewer areas of drought across the state, and less severe levels of drought in northwest Iowa. Information on how the US Drought Monitor is developed can be found on the US Drought Monitor website.
Look for updated survey results next spring, or 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 November 13, 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
