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Home > Protecting Our Lands & Waters > Clean Water Fund > Groundwater & Drinking Water Protection > Water Quality and Irrigation Research at Rosholt Farm > Research Design, Sampling, and Weather Data

Research Design, Sampling & Assessments, Weather Data


The research design, treatments and research questions were the same at both the Rosholt Farm and Dakota County location.

  • Three crop rotations; corn on corn, corn following soybeans, and soybeans following corn
  • Nitrogen practices included different products, rates and application times. Nitrogen rates range from 0-280 lbs/ac. View a table of Nitrogen Rates and Treatments.
  • Plots were irrigated by a linear irrigation system at Rosholt Farm and under a center pivot in Dakota County

Water Sampling & Plant Assessment Person pouring a water sample into a Hach Ultraviolet Spectrophometer for nitrate analysis

Water that escaped below the root zone of growing crops was analyzed for both volume and nitrate-nitrogen concentration. Suction tube lysimeters were used to collect soil water for nitrate analysis while drain gauges were used to measure he soil and water volume. Both pieces of monitoring equipment were buried in trenches below the surface so normal tillages and other farming operations could be performed.

Water samples were collected once per week during the cropping seasons (May-October) and after any significant rain event. Water samples were analyzed on-site using a Hach Ultraviolet Spectrophotometer (image to right). Additionally, researchers used high-tech, in-field chlorophyll meters to measure plant nitrogen concentrations and provide information about plant nutrition during the growing season.

Weather Data

At Rosholt Farm, a weather station capable of measuring minimum and maximum daily temperatures,Ag weather station wind speed, relative humidity, solar radiation, and rainfall was installed. These measurements are used to calculate local evapotranspiration (ET) potential. Having a weather station on-site provides an accurate method of identifying crop water needs and helps eliminate under and/or over-watering. Access to information about local climate conditions enables crop producers to apply the right amount of water at the right time, minimizing the loss of water and nutrients.

The weather data from this site is available on-line through the Ag Weather Network and has gained popularity with local Coops, irrigators and the general public.

 

 

 

MDA Contacts

Dan Langseth
Fertilizer Management Adviser
Dan.Langseth@state.mn.us ~ 320-808-5834
Rosholt Farm

Ryan Lemickson
Fertilizer Management Adviser
Ryan.Lemickson@state.mn.us ~ 612-209-9181

Bruce Montgomery
Fertilizer Section Manager
Bruce.Montgomery@state.mn.us ~ 651-201-6178