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How Much Moisture Do Cover Crops Use

How Much Moisture Do Cover Crops Use,
NRCS in Kansas Collecting Soil Moisture Data

By Gary Parks, Soil Scientist
Natural Resources Conservation Service
Hutchinson, Kansas

The soil health initiative is happening nationwide. There has been much publicity, acceptance, and some downright skepticism throughout much of the United States. Here in Kansas, there is a considerable amount of interest. However, without hard data to show local producers interested in the concept, even on a relatively small scale, it’s a hard step to take.

“Why would I want to grow a cover crop when I’m trying to conserve soil moisture for my cash crops?” “We don’t have enough rain in our part of the country.” “That will never work here, it is just too dry of a climate.” “How much moisture does the cover crop use up?” These are common concerns and questions when discussing cover crops with many producers.

Kansas has a wide range of annual precipitation. The precipitation ranges from less than 16 inches in the western counties to 48 inches in the southeastern corner of our State. In an attempt to answer questions and provide data to our customers, the Natural Resources Conservation Service (NRCS) and local area producers are working together. A five-year cooperative study to monitor and collect soil moisture changes between no-till and no-till with cover crops is underway. The study is taking place state wide on lands where producers want to help provide answers for their neighbors and NRCS. Study locations include: Barber, Cloud, Decatur, Ford, Gove, McPherson, and Wallace counties. Prior to any equipment being placed in the ground, each site has a full soil profile description documented; active carbon samples are collected from each plot randomly and mixed together for a composite sample. Bulk density samples are collected for horizons where sensors are placed: 4, 8, 14, 20, 36 and 48 inches. The data will be collected at least quarterly during the five-year study. The data will be reviewed for each download for trends, problems, or malfunctions in the equipment.

General Study Requirements:

It is preferred that the study sites have been in no-till for a minimum of three years; plot sizes of 200 by 500 feet (2 plots) or alternating treatment strips of 150 by 150 feet are laid out. The soil must be uniform within the plots, and benchmark soils are preferred for the study. There are four data loggers per field to monitor soil moisture. Soil moisture will be monitored at 4, 8, 14, 20, 36 and 48 inches. One data logger will monitor soil temperature and log the rain gauge, with soil temperature recorded at 4 inches (4 sensors) and 20 inches (1 sensor).

The study participants (landowners) are committed to allow the study to take place for five years, plant a cover crop mix of at least three species in the no-till with cover crop plot annually. The timing of planting is dependent on the cash crops grown so it may be summer, fall, or spring.

A fall planting that is carried into the spring and allowed to grow until termination before planting the cash crop can count for an additional year.

NRCS state, area, and local offices will install the equipment, conduct soil sampling, and troubleshoot any equipment issues. The local NRCS office will collect data from data loggers quarterly, and be available to move fence posts and data loggers at planting and harvest. This is expected to create 8—10 visits to the site per year.

For more information on soil health, please contact your local NRCS office or conservation district office located at your local county U.S. Department of Agriculture (USDA) Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.