This practical "how-to guide" provides guidance on using conservation tillage under furrow irrigation to growers, crop consultants, and public sector practitioners. This guide incorporates 4 years of field research done near Fort Collins and years of work done on the Western Slope as well as wisdom and experience of local farmers practicing conservation tillage.
Project Field Work
A demonstration site comparing three tillage systems has been established at the CSU Agricultural Research, Development and Education Center (ARDEC) north of Fort Collins, Colorado on a dedicated 14 acre field. We are using strip-till, modified no-till, and conventional tillage equipment in field-length plots (>1000ft), each replicated twice within the field to control for variability.
To demonstrate that tillage systems under furrow irrigation are possible with high amounts of residue, the plots are managed under continuous corn using appropriate fertility, insect, and weed best management practices for the area. Crop measurements during the growing season include emergence date, population count, and crop growth stage progression.
Runoff during irrigations is quantified using furrow flumes and recording pressure transducers. Irrigation advance times have been quantified for all systems using an average of the first five furrows progressing to the end of the row. We collected water samples for all five irrigations during last season's growing season, and will collect several times this season.
Three composite water samples will be collected, one initially, one an hour, and one two hours after runoff begins. Samples will be analyzed for total soluble N and P, ortho-P, nitrate-N. We quantify sediment in water samples using Imhoff cones.
We schedule irrigation timing and amount according to soil moisture tension measured using WaterMark resistance blocks and crop evapotranspiration (ET) from the Colorado Agricultural Meteorological (CoAgMet) weather station located on ARDEC, and neutron probe data. Grain yield is quantified from each system using a grain combine with a GPS enabled yield monitor.
In order to conduct an economic comparison of the systems considered, input costs are tracked throughout the cropping season. These included, but are not limited to, labor requirements for all field work, fuel, and fixed and variable equipment costs for tillage operations, fertilizer, pest control and harvest.
The farmer-managed demonstration site(s) were used for our field day last year and will hopefully be utilized again this year. They also serve as sites for educational video production and crop production according to their crop rotations. Crops in the rotation may include corn, sugarbeets, or drybeans. Watermark sensors may also be installed in these fields for soil moisture monitoring to aid in irrigation scheduling and track soil moisture through-out the growing season.