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

Final Report for SW99-056

Project Type: Research and Education
Funds awarded in 1999: $142,380.00
Projected End Date: 12/31/2004
Matching Non-Federal Funds: $15,810.00
Region: Western
State: Colorado
Principal Investigator:
Dr. Abdelfettah Berrada
Colorado State University-Southwestern Colorado Research Center
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Project Information

Abstract:

Winter wheat after a 14-month fallow produced the best seed yield in two out of four years, due to earlier planting and more available soil moisture at planting. Soil moisture availability and wheat yield were enhanced by MT and NT management. Wheat-based systems that included a crop each year were less successful due to the dry conditions that prevailed throughout the study period (2000-2004). The Wheat-Corn-Bean rotation showed promise but it was not clear how corn benefited the system. More research is needed to determine the optimum cropping intensity in the unique environment of southwestern Colorado and southeastern Utah.

Project Objectives:

Research objectives:

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

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

Educational objectives:

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

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

Introduction:

The project area includes Dolores, Montezuma, and San Miguel counties in southwestern Colorado and San Juan County in southeastern Utah. Approximately two-thirds of the cropland (350,000 acres total) in the project area is non-irrigated. Crop yields are limited by the low and erratic precipitation (long-term annual average of 13 to 16 inches), the short growing season (100 to 150 frost free days), and poor soil fertility. The two major crops, winter wheat and dry bean (primarily pintos), produce an average of 20 bu/acre and 400 lb/acre, respectively (http://www.nass.usda.gov/co/, http://www.nass.usda.gov/ut/).

The combination of fine, weakly structured, silty soils and relatively steep sloping terrain (predominant slopes are 1 to 6%) subjects this primarily “clean” tilled area to potentially severe water erosion. The principal erosion hazard is due to spring runoff from melting snow and occasional high intensity rains in late summer or early spring. Wind erosion is not as serious a threat as water erosion but can be severe in the springtime on bare ground, particularly in dry years.

One way to minimize soil erosion is through minimum- and no-till practices. The adoption of such practices in the project area is lagging compared to other regions in the United States, based on reports published by the Conservation Technology Information Center. Farmers’ concerns about conservation tillage include problems associated with operating edible dry bean equipment in wheat residue and maintaining adequate weed and insect control. Research results at the Southwestern Colorado Research Center show that winter wheat can be grown successfully with no-till (NT) and minimum-till (MT) management systems in either the wheat-bean or the wheat-fallow sequence (Berrada et al., 1995). In contrast, NT dryland dry bean production was not successful. Bean yield in NT systems was significantly lower than in conventional systems, even though soil water storage had been improved by the NT practice. Surface soil compaction appeared to be the primary constraint in NT beans.

Minimum-till wheat-bean management would compete better with conventional tillage than NT. However, the use of herbicides should be minimized to make the system profitable. Timing of tillage and herbicide application is essential to achieving good weed control. Fall tillage may be replaced with an application of glyphosate (Roundup) or glyphosate + 2,4 D to control volunteer wheat and winter annuals. Leaving as much crop residue on the soil surface as possible during winter and early spring should help conserve valuable moisture. One or two timely subtillage operations in the spring will control troublesome weeds such as Russian thistle (Salsola tragus L.), prickly lettuce (Lactuca serriola L.), and volunteer wheat that may have emerged in the spring. Trifluralin (Treflan 4EC) applied at 1 pt/acre and incorporated as close to bean planting as possible could be used to control redroot pigweed (Amaranthus retroflexus L.) and prostrate pigweed (A. blitoides S. Wats.).

Wheat-bean rotation should be preferable to wheat fallow since it produces a crop each year. Residual N from the bean crop should enhance wheat yield and its protein concentration. A positive wheat yield response to up to 60 lb N/acre was observed at the Southwestern Colorado Research Center (Stack and Fisher, 1992). The primary objective of fallowing in semi-arid environments is to allow as much soil moisture storage/availability as possible to minimize crop failure. Dry beans, however, obtain most of their water from the upper two feet of soil, thereby leaving some subsoil moisture to the wheat crop (Brengle., 1970; Yonts, 1996). Winter wheat after dry bean is usually not planted until early to mid October, but a September planting is more desirable. Late planting not only reduces wheat yield, it also increases the risk of soil erosion because wheat plant establishment may not occur until early spring (Hammon et al., 1999).

Most of the cropland in the project area is in CRP, alfalfa, winter wheat, dry bean, or pasture. Minor crops include oat, safflower, corn, and chickpea. Chickpea can be grown using similar equipment and production practices as with dry bean. Chickpea is more frost tolerant than dry bean and, thus, can be planted earlier. Competitive chickpea yields and good seed quality have been produced in southwestern Colorado, but late planting and/or late summer rains can delay maturity and increase the incidence of green and stained seeds (Berrada et al., 1999). Little information is available on how chickpea and other minor crops fit within the soil-climate-cropping systems of southwestern Colorado and southeastern Utah.

Research

Materials and methods:

Sites and experimental design:

One field trial was established in 1999 at the Southwestern Colorado Research Center in Yellow Jacket, CO and two on farmers’ fields in 2000. The on-farm trials were located at Eastland, UT and Goodman Point, CO. The choice of cropping systems was based on previous research results and growers’ interests. Conventional tillage was compared to MT management in winter wheat-fallow and winter wheat-dry bean rotations, at Yellow Jacket and Eastland. Alternative crop rotations at these two locations were managed using MT only. Cropping systems tested at each location are listed below.

Site: Yellow Jacket, CO
1. Conventional Tillage Winter Wheat-Fallow (CT Wheat-Fallow)
2. Minimum Tillage Winter Wheat-Fallow (MT Wheat-Fallow)
3. Conventional Tillage Winter Wheat-Dry Bean (CT Wheat-Bean)
4. Minimum Tillage Winter Wheat-Dry Bean (MT Wheat-Bean)
5. Minimum Tillage Winter Wheat-Safflower-Spring Oat (Wheat-Safflower-Oat). This treatment was changed to Wheat-Safflower-Fallow in 2002.
6. Minimum Tillage Winter Wheat-Safflower-Dry Bean (Wheat-Safflower-Bean)
7. Minimum Tillage Winter Wheat-Chickpea (Wheat-Chickpea)
8. Minimum Tillage Winter Wheat-Corn-Dry Bean (Wheat-Corn-Bean)
9. Three-year alfalfa (Alfalfa)

Site: Eastland, UT
1. Conventional Tillage Winter Wheat-Fallow (CT Wheat-Fallow)
2. Minimum Tillage Winter Wheat-Fallow (MT Wheat-Fallow)
3. Conventional Tillage Winter Wheat-Dry Bean (CT Wheat-Bean)
4. Minimum Tillage Winter Wheat-Dry Bean (MT Wheat-Bean)
5. Minimum Tillage Winter Wheat-Safflower-Fallow (Wheat-Safflower- Fallow)
6. Minimum Tillage Winter Triticale-Corn-Safflower (Triticale-Corn-Safflower).
7. Minimum Tillage Winter Triticale-Dry Bean (Triticale-Bean)

Site: Goodman Point, CO
1. Three-year chickpea monoculture (Chickpea)
2. Three-year dry bean monoculture (Pinto Bean)
3. Winter Wheat-Chickpea rotation (Wheat-Chickpea)
4. Winter Wheat-Dry Bean rotation (Wheat-Bean)

The elevation at the three sites ranges between 6800 and 6900 ft. above sea level. The frost-free season is 100 to 120 days for summer crops such as dry bean. Normal precipitation (1971-2000 average) at Yellow Jacket is 15.9 inches per year, of which approximately 40% comes from snow (http://www.wrcc.dri.edu/index.html). Monthly average precipitation ranges from 0.6 to 1.9 inches, with June being the driest month. Precipitation amount and distribution is similar at Eastland and Goodman Point. The soil is also similar. It consists of wind-deposited material overlying sandstone (Price et al., 1988). The predominant soil type at Yellow Jacket and surrounding areas is Wetherill loam (fine, silty, mixed, mesic Aridic Haplustalfs). It is well drained, deep to moderately deep, and suitable for cultivation of annual and perennial crops, except on steep slopes where soil erosion hazard is high. Slopes of 1 to 6% are common in the cropland.

Each phase of each crop rotation was present each year. Therefore, there were 20 treatments at Yellow Jacket, 16 at Eastland, and six at Goodman Point. The treatments were assigned at random to the plots within each block (Randomized Complete Block Design). The number of blocks (replications) was three at Yellow Jacket and two at Eastland and Goodman Point. Plot size was based on land availability and equipment size such as planter and combine width. Plots were 42.5 ft. x 140 ft. at Yellow Jacket, 120 ft. x 400 ft. at Eastland, and 38 ft. x 2640 ft. at Goodman Point.

Plot management:

The staff at the Southwestern Colorado Research Center managed the field trial at Yellow Jacket. The farm owner managed the trial at Goodman Point. Three farmers and the research staff were involved in the management of the trial at Eastland. The farm owner and his assistant planted and harvested wheat and safflower and did most of the tillage. Another farmer planted and harvested pinto beans and a third farmer planted and harvested corn. The farm owner at Eastland received half of the bean and corn crops, in cash. This arrangement was made because the farm owner did not have the equipment to grow beans or corn. The principle investigator and the project field coordinator assisted with fertilizer and herbicide application and other field operations at Eastland, on an as needed basis.

Cultural practices in CT Wheat-Fallow and CT Wheat-Bean were typical of those used by dryland farmers in the project area. Minimum-till management was based upon the best practices developed at the Southwestern Colorado Research Center, the type and availability of tillage, planting and spraying equipment, and other factors such soil condition and weed infestation. The basic premise was to leave as much crop residue on the soil surface as practical, while minimizing the use of herbicides to keep the costs down.

All the plots at Goodman Point were managed conventionally with heavy reliance on tillage to control weeds. No fertilizer was applied to any of the treatments throughout the duration of the experiment (2000-2003). The whole plot area was in alfalfa in 1993 to 1999. No fertilizer was applied to the CT treatments at Yellow Jacket and Eastland. Nitrogen, P, or Zn fertilizer was applied to the MT treatments based on soil test results. None of the treatments were fertilized in 2002-03 due to drought.

Measurements:

Climatic Data: Precipitation and temperature data were obtained from the Yellow Jacket weather station, which is fairly representative of the climatic conditions at the other two sites. On-site measurements of rainfall were made with a rain gauge.

Soil Testing: Composite soil samples were taken prior to fall and spring plantings at each site and in December 2003 in selected treatments at Yellow Jacket. Sampling depth was generally 0 to 1 ft. and 1 to 2 ft. except when the soil was too dry, in which case only the top foot was sampled. The soil was analyzed for pH, organic matter, and available N, P, and Zn.

Soil Water Availability: Soil samples were taken with a hydraulic probe before planting and after harvest of each crop, in 1-foot increments, down to 4 ft., depending on soil conditions. No measurements were made at Goodman Point in the fall of 2001or 2002. The soil samples were weighed, dried for 48 hours at 105oC, and re-weighed to determine their water content. Bulk density values used to convert soil water content by weight to soil water content by volume were obtained from previous experiments at Yellow Jacket. The wilting point of representative soil samples was determined with the pressure chamber method. Available water is the difference between total soil water at field capacity minus water content at wilting point. When the difference was < 0.0 available water was set to zero.

Soil penetration resistance: Penetration resistance, utilizing a manual push cone penetrometer, was measured at the 0 to 12-in soil depth (0 to 18 in. in 2001), in 2.0-in. increments. Measurements were made in June 2000 and 2001 at Yellow Jacket only.

Crop Yield: Seed yield at Eastland and Goodman Point was estimated from the whole-plot weight. The harvest from each plot was loaded into a truck and weighed with a commercial scale at the nearest grain elevator. A sample was taken from each plot to determine test weight, percent moisture, and/or percent protein. Corn at Eastland was chopped for silage and weighed in the same manner as the grain crops. Its moisture content was determined by drying three samples in an oven at 80o C, for 48 hours.

Wheat, oat, safflower, and corn at Yellow Jacket were harvested with a plot combine in two 4 ft. x 140 ft. strips. The seed was cleaned and weighed. Seed test weight, percent moisture, and percent protein (wheat and triticale) were measured as well. Chickpea and pinto bean were undercut with knives mounted on a tractor, raked with a bean rake, and left in the field to dry for one to two weeks. A 40- to 60-ft. section of a representative windrow was threshed with a plot combine. The seeds were cleaned and weighed and a sample was saved for test weight, moisture, and protein measurements.

Alfalfa at Yellow Jacket was cut once a year, usually by mid June, and baled (small bales) after it was sufficiently dry (18% moisture). The bales were counted and weighed and samples taken from a few bales to determine alfalfa hay percent moisture and relative feed value (RFV).

Crop residues: Crop residues at Yellow Jacket were estimated from three 1.5 ft. by 3 ft. areas per plot, chosen at random. Plant material was removed from the soil surface, put in paper bags, and left to dry for several days before weighing it. The line and point method of evaluating soil crop residue cover was used at Goodman Point and Eastland since the plots were much bigger than at Yellow Jacket. Measurements were made before planting and after harvest. Fewer measurements were made in 2002 and 2003 than in 2000 and 2001 due to drought.

Pest evaluation: Pheromone traps were used to catch pale western (Agrotis orthogonia Morrison) and army cutworm [Euxoa auxiliaris (Grote)] moths at Yellow Jacket and Eastland in the summer and early fall of 2002 and 2003. This was part of a Western Region IPM project (www.cutworm.org).

Research results and discussion:

a. Year 2000

Winter wheat:

Winter wheat yield was about average at Eastland due to adequate fall precipitation and stored soil moisture during summer fallow. A spring application of 40 lb N/acre in MT plots caused a substantial increase in wheat yield (28.9 vs. 23.3 bu/a). Wheat protein content was not affected by N application.

At the Yellow Jacket site, winter wheat yield was significantly higher after summer fallow than after spring crops. The lowest yield was obtained after chickpea, probably due to extensive soil moisture extraction by chickpea as compared to pinto bean, which has a shallower root system. Winter wheat after spring oat failed completely due to too much competition from volunteer oat.

Spring crops:

Extremely dry conditions throughout most of the 1999-00 season resulted in complete failure and/or poor yield of spring crops and alfalfa at all three sites. Pinto beans and chickpeas were planted the same day at Goodman Point. Usually, pinto beans are not planted until early to mid-June to avoid the possibility of a killing frost. Chickpeas are more frost tolerant and can be planted two to six weeks earlier than pintos. Pinto beans were not harvested and chickpeas only averaged 141 lb/acre. The combination of severe drought and low soil moisture content at planting contributed to the low yields at Goodman Point. The whole field had been in alfalfa for seven years until late summer 1999 when alfalfa was killed using a noble blade implement. The farm owner-operator used to grow mostly winter wheat and pinto beans. However, because of low wheat prices and the desire to minimize production costs, he switched to an alfalfa (7 yr.)-bean-chickpea rotation. All the chickpea and some of the pinto bean acreage were grown organically, allowing for a higher margin of profit than traditional farming. Alfalfa is grown for hay and averages 1 to 2 tons/acre/year at $80 to $100/ton. Alfalfa is known to improve soil structure and fertility and minimize soil erosion. We hypothesize that alfalfa, because of its taproot system, used up most of the available soil moisture prior to its termination in 1999. The fall of 1999 was extremely dry, as were the months of December, February, and April allowing for very little recharge of the root zone prior to the planting of pinto beans and chickpeas on 18 May. Additional stress may have resulted from too much residual N (60 lbs in the top 2 ft.), which could have favored vegetative growth at the expense of seed production.

b. Year 2001

Climatic conditions:

Cumulative precipitation from Oct. 2000 through Sept. 2001 was 11.4 in. or 72% of normal. Only the Oct’00, Apr’01, and Aug’01 precipitation was above normal. A late freeze on 13 Jun. caused considerable damage to pinto beans at Goodman Point and to corn at Yellow Jacket. The corn grew back because the growing point was below the frost line but the beans had to be re-planted. There was also some damage to winter triticale (10 to 15% of aborted seeds) at Eastland, UT.

Winter wheat and winter triticale:

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 nitrate N 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 the toe slope produced much more wheat than those situated in the summit.

Spring crops:

The frequent rains in August helped boost bean yield because they occurred during flowering and pod formation. Conversely, they delayed chickpea maturity and harvest by promoting new growth. Chickpea yield at Yellow Jacket was very low (192 lb/acre), primarily due to 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 CT Wheat-Bean and bean after corn in MT Wheat-Corn-Bean 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-à-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.

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 oat. 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 reduced the incidence of pigweed and Russian thistle but did not affect safflower yield at Eastland. The effectiveness of Treflan was probably reduced by the dry conditions during and following its application.

c. Conclusions–2000 and 2001 Results

Winter wheat yield at Yellow Jacket was much higher in 2001 than in 2000 due to more rain and snow 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) cropping systems. Wheat yield in Wheat-Chickpea and Wheat-Corn-Bean was similar to that of 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. Both treatments had similar soil N and P soil test levels at planting. 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 (14 Sept.) and wheat after chickpea (27 Sept.) was well established in the fall of 2000, providing little opportunity for weeds to thrive, and eliminating the need for an herbicide application in the spring of 2001. All other wheat was seeded on 17 Oct. and did not emerge until January or 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 nitrate N at planting in wheat following bean, except in CT Wheat-Bean, than in wheat following fallow. More information on the 2000 and 2001 results can be found in Berrada et al. (2002).

d. Year 2002

Climatic conditions:

The 2001-02 crop season was one of the driest on record in the Four Corners area. It followed two years of below-average precipitation. The cumulative precipitation at Yellow Jacket, from October 2001 through August 2002, was 3.5 in. or 24% of normal. September rainfall was above normal (2.68 in. vs. 1.56 in.) but came too late for most of the 2002 crops.

Winter wheat and winter triticale:

Winter wheat production at the Yellow Jacket site averaged 12.5 bu/acre with a big difference between wheat after fallow and wheat after spring grains. Wheat after a 14-month fallow averaged approximately 21 bu/acre compared to 4 bu/acre (0 to 8.7 bu/acre) on average for wheat after pinto bean, chickpea, corn, oat, or safflower. The higher wheat yield after fallow is likely due to earlier seeding and more available soil moisture at planting. This is similar to what happened in the Year 2000, although wheat yields were generally higher in 2000 than in 2002 due to slightly better weather conditions in 2000. Wheat after fallow produced significantly more grain with MT (24.7 bu/acre) than with CT (17.2 bu/acre) management in 2002 at Yellow Jacket, which could be attributed to more available soil moisture at planting with MT.

Winter wheat production at Eastland and Goodman Point was worse than at Yellow Jacket because of late planting and low moisture availability. At Eastland, wheat after fallow was re-seeded twice due to soil crusting and did not emerge until spring e.g., at the same time as wheat after pinto bean. Still, wheat after fallow (11.4 bu/acre) out-produced wheat after beans (4.3 bu/acre). Winter triticale produced approximately 6 bu/acre after pinto beans and less than 1 bu/acre after corn (after safflower). Wheat after pinto beans averaged 4.7 bu/acre at Goodman Point. Wheat after chickpeas produced less than 1 bushel per acre both at Yellow Jacket and Goodman Point. Wheat protein averaged 19% at Goodman Point, 17% at Yellow Jacket, and 15% at Eastland.

Spring crops:

At Yellow Jacket, oat, safflower, and corn had good emergence and stand but ran out of water quickly. Chickpeas and pinto beans were planted in mostly dry soil resulting in poor emergence and growth because there was very little precipitation through July. Similar conditions existed at Eastland and Goodman Point. None of the spring crops were harvested at any of the experimental sites. Safflower production at Eastland was estimated at 150 lb/acre in Wheat-Safflower-Fallow and 400 lb/acre in Triticale-Safflower-Corn.

Cutworm activity:

Cutworm activity was monitored at Yellow Jacket and Eastland as part of the Western Region IPM Cutworm Regional Survey and Forecast Project. Cutworm outbreaks represent serious but sporadic events in southwestern Colorado and southeastern Utah. The main crops that are attacked are winter wheat and alfalfa. The two main species of concern are the army cutworm [Euxoa auxiliaris (Grote)] and the pale western cutworm (Agrotis orthogonia Morrison). Very little cutworm activity or crop damage was observed in 2002. Adult cutworm moth totals (average of two traps) for Eastland were 484 pale western cutworms and 213 army cutworms during an 11-week period in August through October. This corresponds to a high risk for potential damage in 2003 from pale western cutworms and a low risk for potential damage from army cutworms. The moth totals for Yellow Jacket were 369 pale western cutworms and 1473 army cutworms in 13 weeks (20 Aug. to 12 Nov.). These numbers correspond to a high risk for potential damage in 2003 from both species. The threshold for potential damage the following spring is 200 moths for pale western cutworm and 800 moths for army cutworm.

e. Year 2003

Climatic conditions:

Cumulative precipitation at Yellow Jacket from October 2002 through September 2003 was 12.8 in. or 80% of normal. Precipitation in April through August 2003 was 44% of normal.

Wheat production at Yellow Jacket:

Winter wheat production at Yellow Jacket averaged 25.4 bu/acre, with significant differences among treatments. Wheat after pinto beans or chickpeas produced the highest yield (26 to 30 bu/acre). Wheat after fallow and wheat after bean after safflower (Wheat-Safflower-Bean) produced the lowest yield (22 to 25 bu/acre). Wheat grain protein concentration was highest in MT Wheat-Bean and in Wheat-Safflower-Fallow, and lowest in MT Wheat-Fallow.

Winter wheat was planted on 26 Sept. in all the treatments, unlike in previous years when wheat was planted earlier after fallow than after spring crops. Spring crops in 2002 were not harvested due to extremely low production; therefore, it was possible to plant wheat the same day in all the treatments.

There was very little soil moisture (0-4 ft) at planting, except in MT Wheat–Fallow and MT Wheat-Corn-Bean. MT Wheat-Fallow was managed as No-Till (NT) in 2002 and 2003. No fertilizer was applied to any of the treatments in the fall of 2002 or spring of 2003 due to drought. Soil test results and grain protein concentration indicate that MT (NT) Wheat-Fallow would have benefited from N fertilization. Soil test nitrate N levels in the fall of 2002 were low in MT and CT Wheat-Fallow and adequate in the other treatments based on a yield goal of 30 to 40 bu/acre. The reason for the high soil nitrate N in Wheat-Safflower-Fallow is unknown. Soil test P levels were in the medium range in all the treatments.

Wheat and triticale production at Eastland:

There were no significant differences in wheat or triticale yield among the treatments at P ≤ 0.05. Differences between Wheat-Safflower-Fallow, which had the lowest yield (13.5 bu/acre) and MT Wheat-Fallow, which had the highest yield (21.3 bu/acre); and between MT Wheat-Fallow and CT Wheat-Fallow (15.7 bu/acre) were significant at P = 0.13. The coefficient of variation was 14.9%. Wheat grain protein concentration was low (10.3 to 11.5%) compared to that of triticale (12.6 and 13.4 %).

Wheat at Eastland was planted on 20 Sept. in all the wheat plots, at 75 lb/acre. Triticale was planted on 27 Sept. at 51 lb/acre. Equipment availability dictated the planting date at Eastland. Wheat seeding rate was somewhat high for this environment; 50 to 60 lb/acre is more common. Soil moisture content on 19 Sept. was very low. All the treatments could have benefited from N and P fertilizer, but none was applied due to the perception that the fertilizer would not be economical and could be detrimental to the crop in a drought situation. In addition, soil test results were not available prior to wheat or triticale planting.

Wheat production at Goodman Point:

Winter wheat at Goodman Point was planted on 2 Oct. in dry conditions but was followed with a nice rain. Wheat yield averaged 19 bu/acre, with no significant difference between Wheat-Bean and Wheat-Chickpea. Wheat grain protein concentration averaged 16.5%. Soil NO3-N level in the fall of 2001 and 2002 was high (21 to 25 ppm), while P level was low.

Spring crops:

Spring crop production was generally poor due to dry conditions during the growing season. Soil moisture at planting was adequate but precipitation in April through July was substantially below average. There were no significant differences in dry bean yield at Yellow Jacket or Eastland. Chickpea at Goodman Point produced 52 lb/acre more grain after chickpea than after winter wheat, but the average yield was only 322 lb/acre. More chickpea was produced at Yellow Jacket (653 lb/acre) than at Goodman Point, although seed quality at Yellow Jacket was poor (high percentage of green and stained seeds). Safflower averaged 437 lb/acre at Yellow Jacket and 653 lb/acre at Eastland. At Eastland, safflower produced 236 lb/acre more grain in Wheat-Safflower-Fallow than in Triticale-Corn-Safflower.

No fertilizer was applied to any of the spring crops in 2003, even though soil test N, P, and Zn levels were very low. There was a big drop in nitrate N concentration at Goodman Point in the spring of 2003 compared to the fall of 2002. The high soil nitrate N levels at Goodman Point in 2000 through 2002 were due to the residual effect of alfalfa.

Cutworm damage:

The high moth population in August through October 2002 coupled with favorable climatic conditions (good precipitation and mild temperatures) in the fall of 2002 and winter of 2002-03 resulted in an outbreak of army cutworm. Damage to winter wheat was extensive before the plots were sprayed with Mustang at 2.5 to 3.5 oz/acre. Spraying was completed on 20 Feb., 22 Mar., and 4 Apr. 2003 at Yellow Jacket, Goodman Point, and Eastland, respectively.

f. Conclusions (2002 & 2003)

Wheat and triticale production was extremely low in 2002, with the exception of Wheat-Fallow at Yellow Jacket. Wheat in Wheat-Fallow, at Yellow Jacket, was planted one month earlier than wheat in the more intensive crop rotations. There was more available moisture at planting in Wheat-Fallow, particularly with NT management. No-Till Wheat-Fallow out-produced CT Wheat-Fallow by 7.5 bu/acre due to more available moisture and N and P fertilization.

Wheat after fallow in Eastland also produced more grain than wheat after bean, but the top yield was only 13 bu/acre. Valuable soil moisture and growth potential were lost in Wheat-Fallow and Wheat-Safflower-Fallow, as the wheat was re-seeded twice.

Spring crops produced very little or no seeds in 2002. The generally poor crop yields in 2002 were indicative of the exceptionally dry conditions during most of the growing season. Precipitation from October 2001 through September 2002 was 35% of normal and that from April through August 2002 was 21% of normal. Precipitation for the same periods in 2002-03 was 80 and 44% of normal, respectively. Consequently, crop yields were generally higher in 2003 than in 2002.

At the Yellow Jacket site, Wheat-Bean (CT and NT), Wheat-Chickpea, and Wheat-Corn-Bean produced the highest wheat yields in 2003. No-Till and CT Wheat-Fallow produced similar yields, even though there was more available soil moisture at planting in NT than in CT. No-Till Wheat-Fallow had lower soil test NO3-N at planting and lower grain protein concentration than CT Wheat-Fallow. It could have benefited from N fertilization. Wheat at Yellow Jacket was planted the same day in all the treatments, unlike in 1999-2001. There were no significant differences in wheat yield, among treatments, at Eastland or Goodman Point, in 2003.

Dry bean production in 2003 averaged 382 lb/acre at Yellow Jacket, 412 lb/acre at Goodman Point, and 191 lb/acre at Eastland; with no significant differences among treatments. Beans at Eastland were cut late, resulting in substantial shattering and harvest losses.

g. Overall conclusions

Winter wheat after a 14-month fallow (Wheat-Fallow) produced the best seed yield at Yellow Jacket in 2000 and 2002 and at Eastland in 2002; probably due to earlier planting and/or more available soil moisture at planting, compared to the more intensive crop rotations. A significant decrease in winter wheat yield can be expected when planting is delayed past the optimum date of mid- to late September (Hammon et al., 1999). Wheat after dry bean is usually not planted until early to mid-October. In dry years, such as was the case in 1999-00 and 2001-02, a long fallow period may be necessary to ensure that there is enough moisture at planting for adequate wheat seed germination and stand establishment. Minimum till (2001) and NT (2002 & 2003) management enhanced soil water storage and wheat yield in Wheat-Fallow at Yellow Jacket.

A confounding factor when comparing CT Wheat-Fallow to MT Wheat-Fallow is the fact that MT Wheat-Fallow benefited from N and P fertilization, except in 2003. Conventional Till Wheat-Fallow and CT Wheat-Bean were intended to represent typical farming practices in the project area, which rarely include the application of any fertilizer.

Another confounding factor is the fact that winter wheat after fallow was planted earlier than wheat after a spring crop, except in the fall of 1999 and fall of 2002. We did this because we were more interested in comparing cropping systems than individual cropping practices. Ideally, separate experiments should be conducted to compare CT and MT with and without fertilizer addition and to compare Wheat-Fallow to other crop rotations by varying wheat planting date e.g., 15 Sept., 1 Oct., and 15 Oct.; to match field conditions—time it takes to plant wheat after harvest of the previous crop.

Spring crops did poorly throughout the study period, particularly in 2000 and 2002. Corn appears to be a good crop in rotation with winter wheat and dry bean, for reasons yet to be determined. However, corn yields were low compared to other areas with similar annual precipitation amounts. The short growing season and rainfall distribution (low rainfall in May through mid-July) are not conducive to high corn yields, particularly under dryland conditions. Producing corn for silage is probably a better alternative than producing corn for grain in the project area. With little corn acreage in the project area, corn plots were easy targets for birds, game, and other pests.

Chickpeas did not do as well as expected in rotation with winter wheat. They were planted earlier than pinto beans but often matured later. Uniformity of chickpea seed maturity was a concern when emergence was non-uniform. Chickpeas performed well in other trials at Yellow Jacket but a number of challenges need to be addressed before they can be recommended for large-scale production in the project area.

Safflowers produced around 800 lb/acre in Wheat-Safflower-Bean in 2001 at Yellow Jacket and in Wheat-Safflower-Fallow in 2003 at Eastland. Safflower production potential in the project area is 1200 to 1500 lb/acre with no irrigation. Chemical weed control (Treflan PPI) was beneficial to safflower at Yellow Jacket, but the net receipts per acre were negative. Safflowers, because of their deep taproots, tend to deplete soil moisture more than other crops such as pinto beans or corn. Our data suggest that Wheat-Safflower-Fallow is preferable to Wheat-Safflower-Bean or Wheat-Safflower-Oat in the project area. Growing safflower and dry bean back-to-back on the same field is not recommended due to disease concerns such as bacterial blight, which infects both crops.

Residual soil nitrate N from alfalfa at Goodman Point was high and could have sustained average wheat and bean production for a couple years. However, the combination of dried up soil profile at the end of the alfalfa production cycle (7 years) and below average precipitation in 2000 through 2003 was detrimental to crop production.

h. Literature citations for Section No. 3 and 6

Berrada, A., G.A. Peterson, P.D. Ayers, T.M. Hooten, R.W. Hammon, R.L. Sharp, and J. Skouson. 2002. Developing Sustainable Dryland Cropping Systems in SW Colorado and SE Utah Using Conservation Tillage and Crop Diversification: 2000 & 2001 Results. Agric. Exp. Stn. Tech. Bull. TB02-2, Colorado State Univ., Ft. Collins, CO.

Berrada, A., Mark W. Stack, Bruce Riddell, Mark A. Brick, and Duane L. Johnson. 1999. Chickpea: A Potential Crop for Southwestern Colorado. p. 206-213 In: Jules Janick (ed) Perspectives on New Crops and New Uses, ASHS Press, Alexandria, VA. Proceedings of the Fourth National Symposium ‘New Crops and New Uses Biodiversity and Agricultural Sustainability’, Phoenix, Arizona, November 8-11, 1998.

Berrada, A., M.W. Stack, D.V. Sanford, and A.G. Fisher. 1995. Management systems for dryland wheat and bean production in southwestern Colorado-Conservation tillage project, 1989-93. Agric. Exp. S¬tn. Tech. Bull. TB 95-2, Colorado State Univ., Ft. Collins, CO.

Brengle, K.G., H.O. Mann, and K.A. Schliebe. 1970. Yield and water use with dryland crops in Colorado. Agric. Exp. Stn. Tech. Bull. TB 11, Colorado State Univ., Ft. Collins, CO.

Hammon, R.W., D.V. Sanford, M.W. Stack, A. Berrada, and F.B. Pears. 1999. Dryland winter wheat planting date and Russian wheat aphid studies in southwestern Colorado, 1990-1998. Tech. Rep. TR 99-2. Colorado State Univ., Ag. Exp. Stn., Dept. of Bioagric. Sci. and Pest Management, Southwestern Colorado Research Center, Fruita Research Center.

Stack, M.W., A.G. Fisher. 1992. Winter wheat fertilization for southwestern Colorado: 1986-1989. Tech. Report TR 92-2. Agric. Exp. Stn. Southwestern Colorado Research Center. Colorado State Univ., Ft. Collins, CO.

Yonts, C.D. 1996. Irrigation requirements. p. 24-26 In: Schwartz, H.F., M.A. Brick, D.S. Nuland, and G.D. Franc (ed). Dry bean production and pest management. Regional Bull. 562A. Colorado State Univ., Univ. of Nebraska, and Univ. of Wyoming.

Research conclusions:

This project proved that intensive cropping systems that produce a crop each year were agronomically feasible in the semi-arid environment of southwestern Colorado and southeastern Utah. However, they may be difficult to sustain during extended dry spells, as was the case in 2000 to 2003. The choice of crops in winter wheat-based crop rotations will depend on market conditions, soil moisture availability, known synergies as well as incompatibilities among crops, and other factors. For instance, winter wheat-safflower-dry bean and winter wheat-safflower-oat did not do well in the project area, mainly because safflower dried up the soil profile. Winter wheat-safflower-fallow appears to be more sustainable. The economic feasibility of the dryland cropping systems tested in this project has not been determined.

No-till (NT) and minimum-till (MT) practices were beneficial for they generally allowed more water storage and availability than did conventional tillage (CT). Their impact on soil erosion was not measured but study after study has shown that NT and MT are effective in reducing runoff and soil erosion. Sound nutrient management is essential to the viability of dryland cropping systems, particularly with MT and NT, given the often enhanced water availability and higher C/N ratio compared to CT.

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

a. Outreach
Several meetings were held in Dove Creek, Colorado, between July and December 1999 to explain the purpose of the WSARE project and seek a cooperator from Dolores County. The project objectives and results were discussed at the following events:
– Research Center Conference in Fort Collins, CO on 1/10/01 (20)
– Soil & Crop Science seminar in Fort Collins, CO on 1/18/01 (40)
– Dryland Farming Workshop in Dove Creek, CO on 2/8/01 (55)
– Advisory Board Meeting in Cortez, CO on 2/21/01 (33)
– Colorado Agricultural Experiment Station Managers’ Tour on 6/29/01 (15)
– Field Day and SARE Tour on August 16 and 17, 2001 (124 on Day 1, 12 to 14 on Day 2)
– 2001 ASA Annual Meetings in Charlotte, NC (poster presentation)
(The approximate number of participants is shown in parentheses.)

A workshop was organized on 20 Feb. 2002, in conjunction with the Southwestern Colorado Research Annual Advisory Board Meeting to discuss the 2000-2001 results and explore new avenues for research and education in the project area, such as organic farming and crop rotations involving a cover crop. A total of 34 people attended the workshop. The Principal Investigator later visited with several area farmers and gave presentations at Soil Conservation District meetings in Monticello, UT and in Dove Creek and Cortez, CO to discuss the WSARE project and present a proposal for its continuation beyond 2003. Tours of the field trials were planned for the summer of 2002 but cancelled because of the drought. A limited survey was conducted to find out more about cropping systems, challenges, and farming trends in the project area. This information along with the project and other research results was used in an oral presentation made by the PI at the ASA/CSSA/SSSA Annual Meetings in Indianapolis, IN on November 13, 2002.

The production of a video featuring the WSARE project was scheduled for the spring and summer of 2003 but was cancelled due to personnel changes at the Southwestern Colorado Research Center.

b. Publications

Technical Bulletins:
Berrada, A., G.A. Peterson, P.D. Ayers, T.M. Hooten, R.W. Hammon, R.L. Sharp, and J. Skouson. 2002. Developing Sustainable Dryland Cropping Systems in SW Colorado and SE Utah Using Conservation Tillage and Crop Diversification: 2000 & 2001 Results. Agric. Exp. Stn. Tech. Bull. TB02-2, Colorado State Univ., Ft. Collins, CO.

A second and final Technical Bulletin is being prepared and will be submitted for review in July 2004.

Published abstracts:
Berrada, A. and G. A. Peterson. 2000. Development of Sustainable Dryland Cropping Systems in SW Colorado and SE Utah. Agron. Abstracts p. 132, Amer. Soc. of Argon., Madison, WI.

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.

Berrada, A. 2002. An In-Depth Look at Cropping Systems in SW Colorado and SE Utah. Agron. Abstracts, Amer. Soc. of Agron., Madison, WI. (on CD-ROM).

Popular press:
‘Alternative crop management may increase profit, researcher say’ by Jim Mimiaga. Page 2B in the Cortez Journal, 12/18/99. Account of the meeting held in Dove Creek on 12/9/99 to discuss the SARE project with area producers.

Project Outcomes

Project outcomes:

Enterprise budgets show a negative return for most of the cropping systems tested. This was to be expected because of the exceptionally dry conditions throughout the study period. Further data analysis and interpretation are required before meaningful recommendations can be made based on the economic analysis.

Farmer Adoption

The adoption by area farmers of alternative cropping systems and practices proposed by this project has not been researched. Large adoption would not be expected due to the complexity of the project, its short duration, and drought, all of which limit the scope of the project’s findings. Up to 50 farmers were exposed to this project through direct participation in field trials, field days, and workshops. It is believed that this project contributed to increased awareness of crop diversification, minimum tillage, nutrient management, and organic farming. Farmers need to be flexible and willing to adopt new technologies to adapt to variable market and climatic conditions.

Recommendations:

Areas needing additional study

More time should be allowed for the expression of the soil-climate-cropping systems interactions. The three-year winter wheat-corn-bean should be investigated further, to determine its feasibility. No-till and MT practices in the project area should be refined and adequate training provided for their use. An effort should be made to evaluate alternative crops on a regular basis. The most promising ones should be tested for their suitability in crop rotations. Concurrently, training should be provided on marketing strategies for alternative crops.

The alfalfa-based cropping system at Goodman Point merits more testing, for it offers a potentially viable system for organic bean production in the project area. Alfalfa is one of the major crops in the project area and provides several benefits: protection against soil erosion, N fixation, and soil quality enhancement. There is also a good market for alfalfa hay produced in southwestern Colorado, as well as for organically produced pinto beans and chickpeas.

A big challenge for the sustainability of crop production in the project area is the low level of organic matter and nutrients in the soil. Strategies for enhancing soil fertility should include sound fertilizer management, green manure, and the inclusion of legumes in crop rotations and should be addressed through research and demonstration.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.