Developing Sustainable Dryland Cropping Systems in SW Colorado and SE Utah Using Conservation Tillage and Crop Diversification

Developing Sustainable Dryland Cropping Systems in SW Colorado and SE Utah Using Conservation Tillage and Crop Diversification

Summary

This was the second year of the SARE project in southwestern Colorado and southeastern Utah. The 2000/01 season was not as dry as the previous season but it was 4.5 inches below normal (11.38 versus 15.88 in.). A frost on June 13 caused damage to pinto bean, corn, and triticale. Bean yields were higher in 2001 than in 2000 at Goodman Point and Yellow Jacket in Colorado and Eastland in Utah. Bean after winter wheat in CT wheat-bean and bean after corn in MT wheat-corn-bean produced significantly more than bean after safflower at Yellow Jacket due to more available soil moisture at planting. Winter wheat yield was extremely low at Goodman Point, probably because of the dry conditions in the spring of 2001 and high residual soil nitrogen. Poor wheat stand at Eastland resulted in low yield compared to 2000. Winter wheat yield at Yellow Jacket was significantly higher in MT wheat-fallow than in CT wheat-fallow due to N and P fertilizer and more available soil moisture at planting in MT wheat-fallow. Winter wheat after chickpea or after pinto bean in wheat-corn-bean was similar to MT wheat-fallow. The application of Treflan E.C. in the spring, prior to planting beans (1.0 pt/acre) or safflower (1.5 pt/acre) may not have been needed or effective due to the dry conditions during and after application.

Objectives/Performance Targets

Research Objectives:

1. Determine the effectiveness of alternative soil and crop management systems on crop yield, soil and water conservation, soil fertility, and pest management.

2. Evaluate the costs and returns of these systems in the context of the whole farm enterprise.

Educational Objectives:

1. Increase grower awareness and adaptation of conservation tillage practices.

2. Provide information on alternative cropping systems and how they can be used to enhance the sustainability of dryland cropping systems in the project area.

Accomplishments/Milestones

The 2000/01 season was not as dry as the previous season but it was 4.5 in. below normal (11.38 vs. 15.88 in.). Only the Oct’00, Apr’01, and Aug’01 precipitation was above normal. A late freeze on June 13 caused considerable damage to pinto beans at Goodman Point and to corn at Yellow Jacket. The corn grew back since the growing point was below the frost line but the beans had to be re-planted. There was also some damage to triticale (10 to 15% of aborted seeds) at Eastland, UT.

The “abundant” rains in August helped boost bean yield since they occurred during flowering and pod formation. Conversely, the August rains delayed chickpea maturity and harvest by promoting new growth. Chickpea yield at Yellow Jacket was very low (192 lb/acre), primarily because of poor soil management and weed control. It was much higher at Goodman Point (412 lb/acre) and quite profitable since it was grown organically.

Bean after winter wheat in the conventional tillage (CT) wheat-bean rotation and bean after corn in the minimum tillage (MT) wheat-corn-bean rotation produced significantly more seeds (646 lb/acre)than bean after safflower after wheat (395 lb/acre) at Yellow Jacket. There was substantially less soil moisture in 0 to 4 ft. at bean planting after safflower than after winter wheat or corn. The application of Treflan E.C. at 1.0 pt/acre PPI in MT wheat-bean did not appear to make a difference vis-a-vis weed control and bean yield (495 lb/acre) compared to CT wheat-bean, probably due to the dry conditions in May and June. Treflan application increased bean production costs, which far exceeded the gross income in MT wheat-bean. There were no significant differences in seed yield among the bean treatments at Eastland, UT.

Winter wheat yield at Goodman Point had a good stand and was growing vigorously until about mid-May when it started showing signs of drought stress. The wheat plots were in chickpea or pinto bean in 2000 and in alfalfa in 1993-1999. The combination of high residual soil N-NO3 and dry conditions in May, June, and July contributed to the extremely low yield at Goodman Point (7.3 bu/acre). Winter wheat and triticale grain yields at Eastland were lower in 2001 than in 2000 due to poor stand (50 to 60% of normal), low soil moisture content at planting, and dry conditions during flowering and grain fill. Wheat and triticale yield ranged from 11 to 21 bu/acre, with no significant differences among treatments. There was a large variation in wheat yield between replications 1 and 2 in CT wheat-bean and MT wheat-safflower-fallow due to topography e.g., the plots situated in toeslope produced much more wheat than those situated in the summit.

Winter wheat yield at Yellow Jacket was much higher in 2001 than in 2000 due to higher precipitation in 2000/01 and earlier seeding in three out of seven treatments. Winter wheat in MT wheat-fallow produced significantly more (33 bu/acre) than CT wheat-fallow (24.6 bu/acre) or wheat after bean in the CT wheat-bean (21.3 bu/acre) and MT wheat-safflower-bean (24.0 bu/acre) rotations. Wheat after chickpea and wheat after bean in wheat-corn-bean was similar to MT wheat-fallow. The application of 50 lb of N and 25 lb of P2O5 per acre to MT wheat-fallow in the fall of 2000 greatly enhanced wheat yield compared to CT wheat-fallow, which was not fertilized. There was slightly more available soil moisture at planting in MT than in CT wheat-fallow. The early-planted wheat, i.e., wheat after fallow (Sep. 14) and wheat after chickpea (Sep. 27) was well established in the fall of 2000, providing little opportunity for weeds to thrive, and eliminating the need for a herbicide application in the spring of 2001. All other wheat was seeded on Oct. 17 and did not emerge until January of February. Wheat after bean had a significantly higher grain protein concentration (15.4 to 17.1%) than wheat after fallow (12.1 and 12.8%). The soil tested higher in N-NO3 at planting in wheat following bean, except in CT wheat-bean, than in wheat following fallow.

There was no significant difference in the seed yield of safflower (586 lb/acre avg.) planted after winter wheat or corn at Eastland, UT. Safflower at Yellow Jacket did much better in the wheat-safflower-bean rotation (801 lb/acre) than in the wheat-safflower-oat rotation (220 lb/acre). Wheat in wheat-safflower-oat had failed in 2000 due to drought and too much competition from volunteer wheat. There was adequate moisture for safflower seed germination and stand establishment in both crop rotations but more soil moisture was available in the top 4 ft. in wheat-safflower-bean than in wheat-safflower-oat. Precipitation from planting to harvest was 3.4 in. at Eastland and 4.6 in. at Yellow Jacket. Treflan E.C. was applied at 1.5 pt/acre and incorporated to the soil prior to planting safflower in wheat-safflower-fallow at Eastland and wheat-safflower-bean at Yellow Jacket. It may have reduced the incidence of pigweed and Russian thistle at Yellow Jacket but it did not appear to affect safflower yield at Eastland. The effectiveness of Treflan was probably reduced by the dry conditions during and following its application.

The complete results of the SARE project in 2000 and 2001 will be published in a technical report in 2002. There will be extensive sampling in 2002 to assess the effects of cropping systems on soil physical and chemical properties and a comprehensive analysis and interpretation of the three-year results. There are many factors and interactions that must be considered when analyzing data from cropping systems experiments. We should have a clearer picture of how each cropping system performs at the end of next season (third year of the SARE project) than we do now, given the cropping intensity (two and three-year rotations), and the large variation in precipitation amount and timing from year to year. Hopefully, next year will not be as dry as 2000 or 2001.

Impacts and Contributions/Outcomes

There was excellent collaboration among the farmers, extension agents, NRCS staff, and university scientists and support staff who contributed to the SARE project in 2001. A large amount of data was collected and participation to the outreach activities was generally excellent. The SARE project objectives and results to date were discussed at the meetings and outreach activities listed below. The numbers in parentheses indicate the approximate number of participants, the majority of which were producers and agricultural business representatives.

1. Research Center Conference in Cortez, CO on 1/10/01 (20)
2. Soil & Crop Science seminar at Fort Collins, CO on 1/18/01 (40)
3. Dryland Farming Workshop in Dove Creek, CO on 2/8/01 (55)
4. Advisory Board Meeting in Cortez, CO on 2/21/01 (33)
5. Colorado Agricultural Experiment Station Managers’ Tour on 6/29/01 (15)
6. Field Day and SARE Tour on August 16 and 17, 2001 (124 on Day 1, 12 to 14 on Day 2)
7. 2001 ASA Annual Meetings in Charlotte, NC (poster presentation)
Berrada, A, G.A. Peterson, and R.W. Hammon. 2001. Evaluation of alternative cropping systems in SW Colorado and SE Utah. ASA, CSSA, SSSA Annual Meetings Abstracts, Oct. 21-25, 2001. Charlotte, NC.

In addition, the SARE project was featured in the 2001 Report of the Colorado Agriculture Experiment Station (a copy will be mailed).

The workshop held on Feb. 8 included presentations on dryland wheat, grazing and pasture management and panel discussions on organic farming and value-added products.

There was a notable increase in farmers’ participation to the outreach activities organized by the Southwestern Colorado Research Center in 2001 compared to previous years and could be attributed to the SARE project. There was also an increase in inquiries about crop rotations, alternative crops, cover crops, and organic farming.

Several ideas have emerged on how to enhance the sustainability of dryland cropping systems in southwestern Colorado and southeastern Utah. For example, there is a shift in thinking from two-year rotations to three-year rotations and from conventional farming to more environmentally sound and potentially more profitable cropping systems. These and other ideas will be discussed at a meeting on Feb. 20 in Cortez, CO and could serve as the basis for refining and continuing research on dryland cropping systems in the San Juan Basin. Other activities planned for 2002 include field tours in July and August and a video production on the SARE project.