Triple-cropping Dairy Forage Production Systems Through Conservation Tillage in California's San Joaquin Valley

Triple-cropping Dairy Forage Production Systems Through Conservation Tillage in California's San Joaquin Valley

Summary

This Western SARE project was initiated in 2008 at three San Joaquin Valley dairies to evaluate potential benefits of conservation tillage-enabled triple cropping as a means for producing more silage and thereby removing more manute nitrogen from dairy corrals. Side-by-side comparisons of standard tillage double cropping versus conservation tillage triple cropping are ongoing. Silage growth and nitrogen accumulation have been sampled and soil nitrogen has also been determined at key times during each crop. Silage yields have also been determined for each crop. Data are now being compiled to calibrate a manure N management model that will help guide efficient applications.

Objectives/Performance Targets

The objectives of this project are:

1) to increase the reliability of triple-cropping dairy forage production with the use of CT practices as a means of increasing forage biomass and nutrient uptake by determining production rates and N removal in triple-cropped forage fields compared to standard double-cropped fields,
2) to evaluate triple-cropping compared to standard double-cropping forage production in terms of whole dairy nitrogen budgets and profitability,
3) to extend widely information developed by the project to dairy farmers, consultants and industry groups via a variety of extension education means, and
4) to track changes in the adoption of CT forage production practices in the SJV as evidenced by CT acreage surveys conducted by California’s CT Workgroup and CT equipment sales records

Accomplishments/Milestones

Field evaluations of triple-cropping, the production of three forage crops in a given year, vs standard double-cropping practices have been established at the San Joaquin Valley dairies of Frank Gwerder in Modesto, CA, and Danny Petersen in Turlock, CA. Biomass production and tissue nitrogen content for each of the crops in these dairy silage fields have been sampled and determined at about weekly intervals through the first year. Soil nitrogen has also been monitored at key times during each crop cycle and soil and air temperature information has also been collected. Data from these monitoring activities are now being compiled and summarized. In addition, large-scale field yield determinations have been made in conjunction with each partner farmer. In the coming annual cycle of this study, we will continue with this field monitoring and also use these data to parameterize the APTRAC Manure N Management Model. An adjunct evaluation of twin-row strip-tilled corn vs single-row strip-tilled corn was also initiated at the dairy of Dino Giacomazzi in Hanford, CA.

During the past year of this study, we have also documented two potentially significant constraints of the conservation tillage (CT) practices that were used to facilitate triple-cropping at these dairies. At the Petersen dairy, manganese deficiency occurred in the strip-till triple-cropped corn crop and reduced silage yield. Our current hypothesis as to the cause of this problem is nutrient stratification in the soil of the CT system. To address this situation, a shallow disking was done prior to corn planting in 2009. At the Gwerder dairy, problems aligning the corn planter following strip-tilling were observed and resulted in reduced forage production in the CT system. This situation has been discussed with Frank Gwerder and we are now planning to remedy it in the next corn planting.

During this year, we also took advantage of a visit to California of John Landers, noted no-till expert in Brazil, by hosting public seminars on zero tillage at the dairy farms of Frank Gwerder in Modesto and Tom Barcellos in Tipton, CA. Information related to the goals and initial experiences of this project were also presented at our CT Workgroup’s display at the 2009 World Ag Expo in Tulare, CA in February.

Impacts and Contributions/Outcomes

This project is still in its data collection and summary phase. We are now beginning to dedicate time toward consolidating information that we’ve collected, applying it to the APTRAC N Management Model, and targeting more extension education events for San Joaquin Valley dairy producers.

Collaborators: