Farm and Field

Drainage control systems boost corn, soybean yields

By Herald-Whig
Posted: Jan. 22, 2017 12:01 am

University of Missouri agronomists found corn and soybean yields increase by 20 percent or more when they use drainage control systems.

A combination of drainage and subirrigation boosts corn yields by 45 percent and soybean yields by 20 percent in claypan soils, said Kelly Nelson, MU Extension agronomist at the Greenley Research Center in Novelty where a system allows excess water to drain and be retained as needed.

Nelson said research shows how proper drainage protects the environment and cuts input costs. The drainage water management system reduced nitrate loss by 70 percent and phosphorus loss by 80 percent.

The structures can be described as boxes buried in the ground with slides, or gates, that allow adjustment of the water table in the soil. Water is sped up for drainage or slowed for irrigation, based on soil needs.

The system may not be cost-effective or necessary for all sites. "Benefits must outweigh the cost," Nelson said, who found reduced yields if the system is not properly designed and installed.

Properly drained fields can be planted 10-14 days earlier, often leading to increased yields, Nelson said. MU research shows undrained, saturated fields affect crop health even after a single rainfall event, and excess water flow also leads to soil compaction.

Greenley Research Center plans to upgrade its system in 2017. A large-scale drainage water management system will be installed in cooperation with the Missouri Land Improvement Contractors of America and U.S. Department of Agriculture's Natural Resources Conservation Service at the 240-acre farm. The planned installation includes a large lake and closed-loop system.

More information on drainage research in Missouri is available at greenley.cafnr.org/muds.

Irrigation app

Farmers using irrigation will benefit from a new University of Missouri Extension web application.

Producers can register for the free Crop Water Use web app at www.cropwater.org.

Subscribers receive a dedicated account and website link they can share with farm employees who control irrigation pumps. The application can be used on both mobile devices and desktop computers.

In several watersheds in Missouri, the application will help growers qualify for financial incentives from the Natural Resources Conservation Service by adopting weather-based irrigation scheduling.

CWU estimates crop water use based on data from MU Extension weather stations across the state. Rainfall is estimated from the National Weather Service grid based on latitude and longitude. Crop evapotranspiration (the amount of water lost from plants and soil through evaporation) is calculated from weather data and predicted crop growth stage. Required data in the setup include field location from Google maps and factors such as soil texture, crop type, planting date, rooting depth and irrigation method.

A dryness index warns when soil water deficits are near the irrigation trigger for each field. A unique feature of the application is the projection of irrigation needs in each field for the coming week which helps with spraying, cultivating and labor decisions.

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