As part of the Minnesota Department of Agriculture’s (MDA’s) mission to assist farmers with resource management and protection, the MDA is measuring water runoff quantity and quality from farm fields to determine practices best suited to protect our water and soil resources. One of the tools used in this work is a rainfall simulator. The rainfall simulator produces a storm event with a chosen rainfall intensity to a confined soil surface area. We measure water runoff volume, sediment, and nutrients.
Purpose of on-farm research is to:
- validate research generated on Agricultural Experiment Stations;
- point out differences with Agricultural Experiment Station data; and
- relate to farmers directly through data collection and demonstration.
On-farm research incorporates the complexities of working farms.
What does the rainfall simulator do?
The rainfall simulator is used in on-farm research and demonstration. We are able to apply a storm event with a chosen rainfall intensity to a confined soil surface area, 24’ long by 3’ wide. We measure:
- water runoff volume;
- sediment load;
- phosphorus; and
- nitrogen.
Because we know how much water was applied and how much ran off, we can calculate how much water infiltrated into the soil. By allowing the water to enter the soil, it is available for use by the crop rather than as run-off from the farm field.
Collecting water runoff samples
from a rainfall simulation plot in pasture.
Photo courtesy Mark Zumwinkle, MDA.
Discovery while a rainfall event is occurring:
Most importantly we provide the educational experience for farmers, landowners, and natural resource agents to witness how much water moves off or infiltrates into the soil. This is an opportunity for them to discuss alternatives, to hybridize their management, and to adapt tillage equipment to optimize water flow and crop development (possible win-win).
Observing rainfall infiltrating into the soil provides important insights into the physical properties of soil that affect crop production. These properties include: surface sealing, macroporosity, aggregate stability, and the interaction between these properties, crop residue, and the plant canopy.
Rainfall simulation evaluates the effectiveness of cropping infiltration with systems to maximize water infiltration into the soil. Systems studied includes conservation tillage, cover crops, pasture system, and manure management.
View of the rainfall simulation set-up. Photo courtesy Mark Zumwinkle, MDA. |
Collecting water runoff samples from a rainfall simulation plot in soybeans. Photo courtesy Mark Zumwinkle, MDA.
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MDA Contact
Mark Zumwinkle, Soil Scientist/Researcher
Mark.Zumwinkle@state.mn.us ~ 651-201-6240
Ag Marketing & Development Division
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