Improving Agricultural Sustainability through Drainage Water Management Practices

Improving Agricultural Sustainability through Drainage Water Management Practices

Summary

The impact of controlled drainage on drain flow and water table depth was determined using a modified version of the paired watershed approach.

Controlled drainage was found to reduce drainage outflow during both summer and winter treatment.  The data depicted that controlled drainage was able to maintain water table depth at higher levels in the controlled field than the uncontrolled field.

Preliminary results were presented at the NCR-207 and ADMS-TF (Agricultural Drainage Systems Task Force) spring meetings that facilitated discussions on controlled drainage results from different states.

Objectives/Performance Targets

The main objective of this project was to access the impact of drainage water management on reducing tile outflow from drained fields, increasing available water and crop yield through paired-field studies on three farms in Indiana.
We also formulated intermediate and long-term desired outcomes, although they were not expected to be accomplished during the course of the project. The desired intermediate-term outcomes will:

1. Enable farmers to make more informed decisions on whether or not the adoption of the practice would be profitable for them, and
2. Enable federal, state, local, and non-governmental soil conservation and water quality organizations to make decisions about supporting drainage water management as a best management practice.

The desired long-term outcome is that farmers will adopt the practice (if it is determined to be successful at increasing yield, promoting improved water quality and reducing nitrate losses).

Accomplishments/Milestones

Rating curves were developed using stage measurements from circular flumes and flow measurements. The rating curves were used to estimate flow for periods when there were no flow sensors implemented.  Data collect from actual flow meters and that calculated from rating curves were used to evaluate the effects of controlled drainage. Daily flow measurements were used to analyze the differences between treatments. The repeated measures mixed model was used to replace the ANOVA model of the paired watershed approach in order to account for the serial correlation in hydrologic data.

The water table depth was analyzed both as seasonal averages and using the modified paired watershed method. The average daily water table depth was used for paired analysis and showed that controlled drainage was effective at maintaining the controlled water table at depth closer to the surface most of the time. The seasonal averages also showed that in most cases the controlled water table was closer to the soil surface than the uncontrolled water table.

DRAINMOD simulations were suspended in spring of 2008 in order to revise flow methods that directly influenced the results from the model. The revisions to flow were completed in November of 2008 and did not occur in sufficient time for recalibration of model in 2008.

Future work includes recalibration of DRAINMOD, preparation of dissertation and papers for publication.

Impacts and Contributions/Outcomes

The NCR-207 and ADMS-TF meeting were hosted at Purdue in 2008 and attendees were able to visit one of my research locations. Visitors from across the North Central Region were able to learn of the work we are doing and share their expertise. Detailed results of the impact of drainage water management on plant available water, and on reducing tile outflow will be discussed in the final report.

Collaborators: