Residue Management in Furrow Irrigated Reduced Tillage Systems

OBJECTIVES
The project team wanted to reduce tillage across fields so that it becomes a cost-efficient practice.

ABSTRACT
Randy Hines operates a furrow-irrigated farm in western Colorado near Delta on heavy tight clay soil. His primary crops are corn, pinto beans, alfalfa and some vegetables. Furrow irrigation requires a clean surface, which has meant plowing under the corn stalks for rotations that follow corn. As an alternative to plowing, Hines proposed to build a tillage tool that will incorporate corn stalks into a 60-inch bed, at the same time ripping so he can irrigate every other 30-inch row.

He hopes to show how reduced tillage can replace the moldboard plow by reducing erosion from irrigation and wind, which will promote a healthy and sustainable farming environment. While the high residues present a challenge, Hines says he believes it will work and will be applicable to all types of crops grown in the area.

The trial showed that minimum tillage can be used successfully with crops and soils in western Colorado.

SPECIFIC RESULTS
The tillage tool was assembled using a heavy tool bar and carrier on which to attach the ripper bedders. Rotary tines on another toolbar were specially designed to windrow the stalks into the 60-inch beds.

In 2000, the fields were disked twice then marked out with the ripper-bedder. Fertilizer was applied at the same time. The rotary tines were then used to windrow the stalks, and the corn was planted. Hines says the bedder was built to combine tillage operations, and it did, cutting in half the number of trips across the field before planting. A few uneven beds in a few fields resulted in poor population stands, but the overall corn crop progressed well.

Hines added PAM to the irrigation water in some test strips and noticed reduced sediment washing down the furrows, although the PAM did not greatly influence erosion control. On the other hand, he saved two irrigations on fields under minimum tillage compared with the plowed fields.

"The increase of the organic matter content of the soil has a positive impact on the water-holding capacity of the soil," he says.

Splitting nitrogen applications seemed to work best. When all of the nitrogen was applied at planting, there wasn't enough to carry the crop to summer's end. That may have resulted from excess residue in the furrow, which slowed the water advance, resulting in deep percolation and leaching of nitrogen below the root zone. Or, speculates Hines, it could have been an application problem.

Herbicide application, minimized to a one-pass post treatment, was basically efficient. Field bindweed presented some problems, but an application of 2,4-D in the fall - as opposed to a spring application - provided optimal control with the least impact on corn yields.

In 2001, Hines followed the same tillage practices in the stalks, except that he bedded a little earlier and gusty winds blew residue into some of the furrows.

While corn yields in 2001 were basically the same as in 2000, hybrid response varied by the amount of residue cover in the beds. Those with early growth traits performed better. Hines observed that surface residue affecting seed emergence could be reduced with a residue manager on the planter that would throw the residue away from the irrigation furrow. He tried a modified version with fair results, but suggests that a Yetter version that moves the residue to one side might be the better choice.

Also in 2001, he planted yellow beans in the corn stalks using the same minimum tillage practices used for the corn plantings. He plowed one field for comparisons, which showed the minimum tilled plots used less water and had fewer weeds with no yield reduction.

In just two years, the organic matter has increased to 2% from 1 to 1.2% before the trials. Earthworms are now seen where none were seen before.

Hines is now working on a tillage tool that can be used after harvest in the fall. It will be a one-pass operation that he anticipates will help conserve moisture, allow the beds to warm up in the spring and reduce the incidence of stalks blowing into the furrows.

"The results of this trial, which are still being conducted through trial and error, have been successful," says Hines. "Minimum tillage can be done in our clay type soil with furrow irrigation."

POTENTIAL BENEFITS
Using the results of this project, Hines and other farmers in the area will be able to employ minimum tillage in their operations. Some of the advantages they will find are these:

1. Reduced labor and time owing to fewer trips across the field. A 500-acre farm could save 225 hours.
2. Lower machinery costs, estimated at $5 an acre in reduced wear and maintenance.
3. Reduced operating costs. Minimum tillage reduced average fuel use by 6 to 7 gallons an acre compared with moldboard plowing, which, on a 500-acre farm, would amount to a savings of $2,750. The use of nitrogen fertilizer was also reduced to 0.75 to 1 unit of nitrogen under minimum tillage compared with 1.25 units on plowed ground. In addition, minimum tillage saves on herbicide by reducing herbicide applications to one under minimum tillage from two under plowing.
4. Less soil erosion, up to 90% less in some areas, resulting in less silt in rivers and less runoff of fertilizers and pesticides.
5. Reduced water use because of improved infiltration. The crop residue helps the water soak into the soil and results in less loss to evaporation.
6. Increased organic matter, which encourages microbial life, and increased earthworms. Other soil benefits are sequestration of carbon and reduced wind erosion.
7. Improved wildlife habitat because of crop residue providing shelter and food for birds and small animals.

FARMER ADOPTION AND DIRECT IMPACT
Area farmers showed interest in Hines' reduced tillage, and several are experimenting with the practice in their own operations. They have planted winter wheat in minimum tillage corn, onions in hay ground and oat cover crops and corn in bean ground.

"Before our project there was little minimum tillage done in our valley," says Hines. "After seeing the results there are more acres every year not being plowed."

FUTURE RECOMMENDATIONS OR NEW HYPOTHESES
The project's final report recommends providing more funds for the local extension office to follow up on individual projects, which would allow producers to continue managing an economical and sustainable farm enterprise that promotes a sound, healthy environment.

DISSEMINATION OF FINDINGS
Hines shared his project's plans and accomplishments personally with other farmers and through workshops and field days. His farm was visited in 2000 during Colorado State University's Ag Production Field Day, and he shared the results during a grower panel at the CSU Ag Production clinic in the spring of 2001. In the summer of 2001, Hines exhibited his crops and equipment during a CSU field day and demonstration tour, and he was slated to appear at another clinic in the spring of 2002.

In addition, in February 2001 Hines had a bulletin board exhibit at the Ag Forum in Denver, and in October that year the Tri River Conservatory viewed his crops and minimum tillage practices.

PRODUCER INVOLVEMENT
The Randy Hines farm and family were the main producers involved in the project, but it was estimated that an average of 40 producers attended each of the workshops, tours and field days.