Conservation Tillage Benefits in a Cotton Centered Crop Rotation System

Conservation Tillage Benefits in a Cotton Centered Crop Rotation System

Summary

Conservation tillage practices reduced the number of cultural operations required to grow a cotton crop. Barley and grain crop residues and conservation tillage increased the infiltration of irrigation water into coarse-textured soils, slowed irrigation advance times, and increased the amount of irrigation water used at two out of three sites. Adequate cotton weed control was achieved in conservation tillage systems using only postemergence herbicides; weed-sensing, intermittent spray technology reduced the amount of spray volume and herbicide used. Cotton yields in conservation tillage systems were similar to the yields in conventional tillage systems at two sites and greater at Coolidge.

Objectives/Performance Targets

The goal of this project is to provide cotton growers in the southwestern United States with the necessary economic, agronomic and physical information required to adopt conservation tillage practices, to utilize cover crops or double crop small grains with cotton, and to utilize weed sensing sprayer technology. To achieve this goal, five objectives/performance targets have been established:

1. Evaluate the planting of cotton into cover-crop residues or into small grain crop stubble without preseason tillage.

A barley cover crop and a barley crop harvested for grain will be planted and then cotton will be planted into either the herbicide-desiccated barley cover crop or into the grain crop stubble using a no-till cotton planter. In addition, a no-till, randomized complete block experiment will be established to evaluate how grain straw and stubble should be managed to obtain optimum growth of the following cotton crop. The effects of variety, height of stubble at the time of cotton planting, removal of straw, and other factors will be evaluated. The no-till treatments will be compared to a conventional cotton production system (i.e., the standard practice treatment) that involves pre-plant discing, listing and shaping of beds on some farms, planting, and cultivation for weed control after planting. Additionally, conventional cotton will be planted following a barley cover crop terminated by discing, and following a barley grain crop. Field preparations prior to conventional cotton planting will include discing to incorporate the grain crop residues into the soil prior to cotton planting. The amount of biomass produced by the cover and small grain crops will be measured by clipping 0.25 m2 quadrats, and percentage of ground covered by residues will be measured after cotton is planted. Agronomic data on cotton and small grain growth and development, and crop yields will be collected.

2. Evaluate a weed sensing sprayer and a post-emergence herbicide weed control program in minimun-till cotton.

Since cover crops and grain stubble can suppress weed emergence, it may be possible to eliminate the use of preemergence herbicides in no-till cotton. This hypothesis will be tested by dividing each subplot in half and treating one half of each plot with pendimethalin (a soil applied preemergence herbicide) following cotton planting. Roundup Ready cotton varieties will be planted in all experiments and prior to the fifth true-leaf cotton growth stage, Roundup (glyphosate) will be sprayed over the crop row in all treatments. At later growth stages Roundup and other herbicides will be post-directed at the base of the cotton plants. In the minimum-till treatments, the inter-row space will be sprayed using a hooded sprayer; two hoods will contain Weed Seeker spray units and other hoods will contain standard continuous spray nozzles. In the conventional cotton treatments, the inter-row space will be cultivated and sprayed as necessary with the growers standard post-directed herbicide sprayer. All cultivations and the volume of spray and the amount of chemical used in all herbicide applications will be recorded in order to determine the economics associated with different weed control practices and the degree to which weed sensing sprayer technology can reduce the amount of herbicide introduced into the environment. Weed control operations will be conducted as needed by treatment in response to weed emergence. The type and density of weed species emerging in all treatments will be recorded at times corresponding to herbicide applications. Data will be used to determine the effects of preemergence herbicide, tillage, cover crop, grain stubble on weed populations and the efficiency of the weed sensing sprayer.

3. Evaluate changes in soil properties such as organic matter content, crusting, water infiltration and associated changes in fertility and irrigation practices.

A variety of soil and water measurements will be made over the 3 year course of this project to document beneficial changes in soil characteristics. The top 12 inches of the soil profile will be sampled prior to cotton planting and after cotton harvest to determine the amount of nitrate nitrogen in the soil for crop fertility management and to monitor changes in soil organic matter content (measured as total organic carbon), carbon/nitrogen ratios and estimated sodium percentage (ESP) . The water holding capacity of the top foot of the soil profile will also be measured gravimetrically. During cotton seedling establishment, the effects of soil crusting and compaction will be monitored by comparing cotton plant emergence relative to the number of seed planted and by comparing cotton emergence between treatments. Early in cotton season when barley residue levels are highest, water infiltration will be measured using ring infiltrometers and irrigation advance times will be measured. Cotton nitrogen status in-season will be monitored using petiole tissue samples. Nitrogen will be applied using traditional side-dress applications in the conventional main plots and by water-run nitrogen in the minimum-till plots.

4. Collect and compare operational, agronomic (i.e., plant growth), and cost data for minimum-till and conventional production systems.

For each experimental site, detailed records of all crop input and field operations including the time required to perform various operations will be maintained along with information on the tractors and other equipment needed to perform operations so that detailed crop budgets can be developed for each treatment. The crop budgets will include both operational costs (cash costs) and equity and capital costs. These budgets are essential to documenting the potential to reduce long-term production costs in conservation tillage systems and the economic benefits of minimum-till cover crop or double crop systems in Arizona. The crop budgets will also document what costs increase or decrease in conservation tillage cotton production systems. An economic analysis of the weed sensing sprayer used in conjunction with other weed control practices will be done to determine if the savings in time and chemical along with eliminating tillage for weed control can justify the capital cost of the Weed Seeker sprayer technology.

5. Disseminate information on alternative production practices.

A multifaceted approach involving field days, Extension meetings, publications and web sites will be used to disseminate the results of the research and the crop budgets and other economic data. We will conduct field days to introduce the project and its objectives at appropriate times, possibly at each experimental site depending on grower interest. We will attempt to demonstrate the impact of cover crops on cotton stand establishment and the method of no-till planting in grain stubble. Preseason or early season meetings with cotton producers will be conducted during the spring of each year and the results obtained to date shared with producers. A survey of meeting attendees will be conducted to solicit input on the project and gauge the level of interest in adopting conservation tillage practices among growers. Research reports will be written following cotton harvest each year and photographs and other information will be posted on a University of Arizona crop production web site. Presentations will also be made at national meetings such as the Cotton Beltwide meetings, the Agronomy Society meetings and the Western Society of Weed Science meeting.

Accomplishments/Milestones

1. Evaluate the planting of cotton into cover-crop residues or into small grain crop stubble without preseason tillage.

Field trails were established in October and November of 2001 by planting barley crops on three commercial farms (Fast Track farms, Coolidge; A Tumbling T Ranch, Goodyear; and John Thude Farms Partnership’s Paradise Ranch) and at an experiment station (University of Arizona Marana Agricultural Center). The experiment at Paradise Ranch encountered numerous difficulties including loss of the first cotton planting due to water management problems with the center-pivot irrigation system. Therefore, no 2001-2002 data will be presented for this site but we are continuing to work with this grower and hope to collect data during the 2002-2003 cropping year. The treatments varied among the three remaining sites and were strongly influenced by what our farmer cooperators were willing to investigate.

Fast Track Farms; Coolidge, AZ; Greg Wuertz
Tillage/cover crop treatments
–Conventional tillage/winter fallow, conventional cotton planting
–Minimum tillage/oat cover crop, no-till cotton planting
–Minimum tillage/Solum barley cover crop, no-till cotton planting

Tumbling T Ranch; Goodyear, AZ; Ron Rayner
–Fall no-till Solum barley planting for grain crop/spring no-till cotton planting
–Fall minimum tillage Solum barley planting for grain crop/spring no-till cotton planting
–Fall minimum tillage Solum barley planting for grain crop/spring minimum tillage cotton planting

University of Arizona Marana Agricultural Center
–Conventional tillage/winter fallow, conventional cotton planting in April (early planting)
–Conventional tillage/winter fallow, conventional cotton planting in late May/early June (late planting)
–Minimum tillage/no-till planting of barley cover crop, no-till early cotton planting
-subplots (3) were Brittle-stem barley, and two subplots of Solum barley
–Minimum tillage/no-till planting of Solum barley grain crop, late no-till cotton planting

Discussions with growers quickly eliminated using wheat in a double crop scenario with cotton because wheat requires several more weeks than barley to reach maturity for grain harvest. Although they were interested in seeing the experiment conducted, particularly Ron Rayner, none of our commercial growers were willing or able to provide sufficient space to investigate straw management aspects of a small grain-cotton double crop scenario. Thus, we added an additional experimental site at the Maricopa Agricultural Center that will be planted in the fall of 2002 to achieve this objective in our proposal. The Maricopa Agricultural Center site will also increase our educational opportunities.

At Coolidge (Table 1), oats and barley cover crops were of similar height (13.2 in compared to 13.0 in) and produced similar amounts of biomass (873.28 kg/A vs. 860.40 kg/A). Individual oat plants were much shorter in stature and appeared to produce far less biomass than the Solum barley on an individual plant basis. However, there were so many barley volunteers in the oat cover crop that most of the biomass in the oat cover crop was barley accounting for the lack differences between treatments. The Solum barley appeared to be a superior cover crop compared to oats when produced on limited resources at Coolidge. At Marana, Solum barley plants were significantly taller than brittle stem barley plants (Table 2); however, there was no statistical difference in their biomass. The barley grain yield at Marana was 7,613 lb/acre. No cover crop assessments were made at Goodyear and grain yields at Goodyear were not measured in spring 2002 because the grower harvested without contacting any of the project participants.

Project participants Clay, Husman, and McCloskey purchased six Yetter Farm Equipment 2976 residue manager/coulter assemblies using non-project funds. These were bolted onto John Deere Maximerge planters at Marana and Coolidge to plant cotton without tillage on beds into barley cover crop residues or barley stubble remaining after grain harvest. The Yetter 2976 residue managers did a good job of moving residue and cutting a seed line with a fluted coulter resulting in good seed placement in the dry beds. At Marana where the soil is a clay loam, substantial weight had to be added to the 4-row planter (about 200 lb/row) to achieve operation of the residue managers and soil penetration of the coulter and planter units. At Coolidge, the combination of a 6 row planter and a sandy loam soil resulted in good soil penetration and it was not necessary to add extra weight to the planter. The Goodyear site was planted with the growers existing cotton planter which was already adapted for no-till cotton planting into grain stubble. Overall the results from the Marana, Coolidge and Goodyear sites indicated that the no-till cotton planting methods did not negatively affect cotton seedling emergence compared to conventional tillage/planting methods (Tables 3-5). However, at Marana, there was a significantly less emergence in the conventional tillage, winter fallow treatment compared to the other treatments. This was caused by the high air and soil temperatures which dried out the seed bed before the germination and emergence were completed despite planting the seed in moisture. The traditional practice in these types of Marana soils in the normal early April to early May planting window is to plant to moisture, however, in the future, late cotton plantings following grain harvest will be dry planted and irrigated to obtain a stand based on this year’s experience.

Work this year identified a major problem that will have to be addressed prior to adoption of minimum or conservation tillage practices. Arizona has a “plow down” requirement following cotton harvest to facilitate pink bollworm control that has the effect of promoting tillage. The regulations require growers to disrupt cotton stem/tap root-soil connections to kill the cotton plants which most growers accomplish by shredding stalks, pulling the roots loose from the soil with a root puller (this step is often omitted) and disking twice. The regulations were recently modified to allow growers to plant a small-grain crop based on data showing that the combination of cold winter temperatures and irrigation of the small-grain crop resulted in a lack of pink bollworm emergence from the cotton stalks in the spring. If we could plant barley on cotton beds after shredding the cotton stalks our experimental fields would be in compliance.

In Marana, we experimented with several types of tillage implements; some specially modified to reduce passes across the field, but were unable to obtain beds that could be planted with a conventional grain drill without using conventional tillage practices. We concluded that not working or physically disrupting the cotton beds and using a specialized no-till grain drill would be necessary to plant barley on cotton beds following cotton harvest and stalk shredding. A suitable no-till grain drill was unavailable in Arizona so at considerable expense ($3,000 of non-project funds) a John Deere 1560 no-till grain drill was trucked to Marana from California to plant the Marana experiment and then shipped back to California. This planter was able to do an excellent job of planting barley on stale cotton beds and had no trouble slicing through cotton stalks/roots. The acquisition of a no-till grain drill is probably the single most important barrier to the success of our tillage project and it will be considerable challenge to obtain one given the cost involved (over $22,000). In addition, we have no experience in trying to plant cotton with the Yetter 2976 residue managers on stale beds containing both decaying cotton stalks and barley stubble or cover crop residues. Thus, this next year of experimental operations at Marana will be quite interesting and should provide much needed information on the adoption of reduce tillage practices in Arizona.

For this objective, more work is needed to determine to what extent tillage can be reduced, the height at which cotton stalks should be shredded to accommodate no-till planting practices and what equipment is required to provide acceptable results in Arizona cotton production systems. In addition, cover crop management and straw management options after grain harvest need to be further investigated to determine optimum conditions for cotton growth and a no-till grain drill needs to be purchased. Our long-term objective is to reduce tillage as much as possible but occasional tillage to rebuild the cotton beds will be necessary after some period of time, perhaps every two or three years. Experience indicates the logical time to do this tillage is in the fall after cotton harvest. However, the types of tillage operations (e.g., SunDance row cultivator with Bigham Paratill ripper shanks) that could be use to accomplish this with a minimum of passes over the field need to be identified and tested.

2. Evaluate a weed sensing sprayer and a post-emergence herbicide weed control program in minimum-till cotton.

An existing 6 row hooded sprayer equipped with Redball model 410 conservation spray-hoods was modified by obtaining two modified Redball 410 hoods and purchasing and installing three WeedSeeker intermittent-spray units from Patchen (now NTech Industries, Inc.) in each 28 in wide hood. Roundup Ready cotton varieties were planted at all experiment sites. A proposed preemergence Prowl (pendimethalin) application was not made at any of the study sites as proposed because the great amount of barley residues and stubble present in the conservation tillage plots was thought to be sufficient to bind and inactivate the herbicide before it reached the soil surface. Thus, weed control in all conservation tillage treatments was obtained using postemergence herbicides.

WeedSeeker spray units under the Redball 410 hoods were compared to conventional continuous spray nozzles in other 410 spray hoods in terms of the spray volume applied and annual morningglory (Ipomoea spp) control which was the predominant weed at Marana. Spray volumes of either application system did not vary significantly between similar treatments but the WeedSeeker hoods applied 48-80% less spray volume and herbicide (Roundup UltraMax) than the conventional nozzle hoods (Table 6). Although weed control was similar in all treatments, initially (07/10/02), annual morningglory control in the Solum barley cover system (61.25%) was significantly lower than in the other treatments and by the final evaluation on 08/02/02, the late-planted cotton/Solum barley grain crop system achieved 99% control, and was statistically better that the others treatments (Table 7). This latter result may have been due to a later planting date and thus smaller weeds being present at the time of application.

At Coolidge, there were small savings of 7 and 5 gallons per acre (GPA) of herbicide spray using the WeedSeeker system compared to the conventional nozzle hoods at the first post-directed spray date in the oat and barley cover crop systems, respectively, for the control of horse and common purslane (Table 8). On 07/16/02, the WeedSeeker system did not provide any spray volume savings among the oats and barley cover crop systems probably due to the poor control of common purslane by the first application of Roundup Ultramax. This poor control resulted in a high density of plants and near continuous spraying by the WeedSeeker spray units during the next herbicide application. The conventional tillage system gave the best control of common purslane by combining mechanical and chemical weed control methods (Table 9). There was no difference in weed control between the WeedSeeker equipped 410 hoods and the conventional nozzle equipped 410 spray hoods. At Goodyear, initial control of volunteer barley and horse purslane using Roundup UltraMax at 26 or 40 oz/A was significantly better than using Select or Fusilade at 8 oz/A and Roundup UltraMax at 40 oz/A tended to give better control of volunteer barley and horse purslane than at 26 oz/A (Table 10). The weed density at the Goodyear site was relatively low, and Roundup UltraMax applied in July resulted in 84-100% control of volunteer barley, junglerice, horse purslane and volunteer alfalfa (Table 11).

For this objective, additional work will focus on improving and optimizing weed control in the minimum or conservation tillage treatments. Weed control can be improved by improving the timing of herbicide applications (i.e., spray smaller weeds) and by using herbicide tank mixtures earlier in the season. In addition, some work on setting the sensitivity of the WeedSeeker units and setting of background is needed to improve weed control and more data is needed on the length of time required to conduct weed control operations for use in the development of crop budgets.

3. Evaluate changes in soil properties such as organic matter content, crusting, water infiltration and associated changes in fertility and irrigation practices.

Soil samples were collected at each site in each plot from the top 12 in of the soil profile at the start of the experiments in the fall of 2001 to evaluate changes soil properties. Because of the potential for changes in the experiments at the end of the first year of work and because laboratory soil analysis results vary from run to run, the soil samples are being stored so samples can be analyzed simultaneously to determine changes in soil organic matter over time. Soil samples will be collected each fall after cotton harvest to monitor soil organic matter content. An additional set of soil samples were collected at each site and analyzed for textural properties as part of the irrigation studies. The Coolidge site contained the greatest amount of sand of three surface irrigated sites (Figure 1). Although there was some variation between depths at Coolidge, overall, the percentages stay fairly constant with clay slightly increasing with depth while sand slightly decreases. With clay contents remaining above 40% in the top 2 ft of the soil profile, the Marana soil contained the highest percent of clay of the experimental sites (Figure 2). The sand and silt contents did vary slightly with a relatively large change at the 2-ft depth. Soil classifications for each layer ranged from clay to sandy clay but overall the soil at Marana would be classified as clay soil. The Goodyear site had a large percent of silt, greater than 50%, throughout the upper 30 inches of the soil profile (Figure 3). The clay content was higher in the top 2 ft and then decreased to almost equal the percentage of sand at the 30-inch depth. The soil types ranged from silty clay loam to silty clay to a silt loam but overall, this soil would be classified as a silty clay loam. Crusting of the soil did not appear to be a problem at any of the sites based on cotton emergence and stand establishment (Tables 3 to 5) and fertility management was similar in both the conventional and minimum tillage treatments.

To assess the impacts of minimum tillage on irrigation practice, two major types of analyses were conducted. The first was to assess the impact of the tillage treatment on infiltration. Minim mum tillage should enhance and increase infiltration, by leaving old root channels intact allow the water to flow deeper through the soil vadose. Also, surface trash should help to slow the advance of the water front, giving increased opportunity time. However, in many situations in surface irrigation, increased infiltration may actually hinder the movement of water down the field, causing excessive water to be applied and reducing irrigation efficiency.

The impact of reduced tillage on irrigation practices was assessed by analyzing infiltration and irrigation water advanced times. Minimum tillage practices would be expected to increase infiltration by leaving old root channels intact allowing the water to flow deeper through the soil vadose. Also, surface organic residues usually slow the advance of the water front resulting in increased opportunity time. However, in many situations in surface irrigation, increased infiltration may actually hinder the movement of water down the field resulting in excessive water use and reducing irrigation efficiency. At Coolidge and Marana, which had furrow configurations, a furrow infiltrometer was used for infiltration assessment; at Goodyear, a double-ring infiltrometer was used. Due to the large sand content in the soil at the Coolidge site, the infiltration rate was high with 10 and 7 acre-in of water infiltrating the soil in a 4-hr period in the minimum and conventional tillage treatments, respectively (Figure 4). The Marana site contained a much higher concentration of clay than the Coolidge site. Both conventional and minimum tillage systems infiltrated an average of 4 acre-in of water with soil almost reaching full saturation in the 4 hr period (Figure 5). The Goodyear site was silty, and the soil was moist at the time of assessment. Within 4 hr infiltration period, an average of 1.5 acre-in of water infiltrated the minimum tillage treatment while 1 acre-in of water infiltrated the conventional tillage treatment with both tillage systems approached a zero infiltration rate at the end of 4 hr (Figure 6). These results indicate that on coarse textured soils, conservation tillage practices did increase infiltration time as expected. In the finer textured soil at Marana there was initially a slightly faster infiltration rate but little difference over the 4 hr measurement period.

At Coolidge, with a fairly shallow slope of 0.06%, irrigation water reached the end of the conventional plots in about 1 hr but did not reach the end of the conservation tillage plot after 8.5 hr (Figure 7). The growers set times for irrigating the conventional and conservation tillage plots were 6 and 12 hrs, respectively. The Marana field had a slope of 0.08% and the average set time for both the conservation and conventional tillage treatments was 8 hrs; however, advance times in wheel rows were shorter than in non-wheel rows (Figure 8). At Goodyear, with a field slope of 0.12%, advance times averaged 3 and 4 hr, respectively, in the conventional and conservation tillage systems (Figure 9). In-field borders placed perpendicular to the water flow were constructed at Goodyear by the grower to slow down the advance of water in the conventional tillage treatment. At Coolidge and Marana, conservation tillage plots (76.5 and 39.38 acre-in, respectively) received more water than the conventional plots (55.5 and 37.19 acre-in, respectively). At Goodyear, both tillage systems received the same amount of water (67.4 acre-in). Thus, as expected, minimum or conservation tillage practices increased irrigation advance times and the amount of water applied to the cotton crop at Coolidge and Marana but the greater field slope at Goodyear appeared to minimize the effect of tillage practices on irrigation advance times and the amount of water applied. At Coolidge, the low slope and low flow rate on a sandy soil led to excessive water use. The long set time meant inefficient irrigation, causing an additional 21 inches of water to be applied. At Marana, a high clay content and additional surface trash on the conservation tillage plots did not impact irrigation management, and flow rate did not differ among the tillage systems. At Goodyear, the presence of surface trash on the no-till plots helped to slow down the water front, an effect similar to the construction of in-filled borders on the reduced tillage plots. The increased irrigation time and water use in the conservation tillage treatment at Coolidge caused difficulties for the grower despite increasing cotton yield (see below). Thus, the Coolidge experiment was reconfigured prior to planting barley in fall 2002 to reduce the size of the experiment and allow the use of borders to better control the irrigation water. It is expected that these changes will allow the grower to apply a greater head of water to the conservation tillage treatments and reduce irrigation times and water use.

For this objective, additional work will focus on continuing to collect soil samples for determining organic matter content and continuing to measure the irrigation infiltration, advance times and water use in all of the experiments. These data will provide information for educational purposes and for developing the crop budgets.

4. Collect and compare operational, agronomic (i.e., plant growth), and cost data for minimum-till and conventional production systems.

Agronomic data was collected at all experimental sites along with the relevant crop production records from both participants and growers. Cotton plant heights in July at Marana were significantly greater in the early-planted cotton/minimum tillage plots compared to the other treatments but plant heights later in the season did not significantly differ among the treatments (Table 12). Height-to-node ratios (HNR) were statistically similar among the treatments. At Coolidge, conventional tillage cotton plants were significantly shorter than the conservation tillage cotton plants (Table 13). While HNR were similar among the treatments initially, the conventional tillage plants later had lower HNR than the conservational tillage plants (Table 13). At Goodyear, the treatments in which cotton was planted without tillage in the spring (i.e., spring no-till) were characterized by taller plants and greater height-to-node ratios (Table 14). Thus, at all sites, treatments with the least amount of tillage were characterized by taller plants with increased height-to-node ratios.

Seed cotton yields Marana showed that early-planted cotton in either a conventional or reduced tillage system significantly out-yielded late-planted cotton (Table 15). Early-planted cotton lint yield in the conventional tillage system (1140 lb/A) was similar to that of the early-planted cotton in the reduced tillage system (1089 lb/A). The late-planted cotton in the conventional tillage system produced the least amount of lint (827 lb/A) and the late-planted cotton in the reduced tillage system produced 927 lb/A. At Coolidge, the conservation tillage systems with either an oat (1007 lb/A) or barley (1089 lb/A) cover crop substantially out-yielded the conventional tillage system (880 lb/A) in terms of lint production by 14.4 % and 23.8 %, respectively (Table 16). This was probably due to the greater amount of irrigation water applied in the conservation tillage treatments as discussed above. There were no differences in cotton yields among the tillage systems at Goodyear (Table 17).

For this objective, additional work will focus on continuing to collect agronomic data at all of the experimental sites including replicated yield data for the grain harvests at Goodyear. Emphasis will also be placed on documenting the cultural practices used in each treatment at each site since it has been somewhat difficult to obtain all of the desired grower records. As our knowledge of the appropriate equipment and cultural practices for conservation tillage at each site increases, crop budgets will be developed to assess the viability of conservation tillage practices as discussed in the objective/performance targets for this objective. After one year of work, our data base of knowledge and experience is not complete enough to allow us to begin working on these budgets.

5. Disseminate information on alternative production practices.

After one year of work, our experience and knowledge base is not yet sufficient to allow us to make progress towards achieving this objective. However, we have raised the awareness in Arizona regarding conservation tillage practices through our routine contacts with growers, through our grower participants talking to other growers, and through a presentation on a farm tour at the Marana Agricultural Center in October 2002. Addition of the Maricopa Agricultural Center site will increase our potential for educational outreach and we look forward to making more progress on this objective in the future.

Impacts and Contributions/Outcomes

In all honesty, the impacts and outcomes of this conservation tillage project are somewhat limited after one year of work. There is a steep learning curve for the adoption of conservation tillage practices and as a group we are still on that curve. We have made considerable progress in identifying the appropriate equipment for conservation tillage practices at each site and in raising the awareness of others regarding conservation tillage practices. For example, our farmer cooperators were impressed with the operation and performance of the Yetter 2976 residue managers. We also improved the Coolidge experiment to make it feasible to conduct the experiment at that site over the long term and we adding the Maricopa Agricultural Center experiment on straw management. However, there is much work remaining to be done. The experiments now in progress and the knowledge gained in the first year of the project will allow us to successfully achieve all of our project objectives in the future.

Collaborators: