Site-specific Manure Management for Improving Soil Quality

Site-specific Manure Management for Improving Soil Quality

Summary

Precision manure management is a multidimensional concept that converges the best manure management practices along with precision agricultural techniques. Our first year of project work indicates that the variable rate application of animal manure across productivity level management zones is potentially a good strategy for enhancing grain yield of low producing areas of the spatially variable farm fields. While, improvements in soil quality (as hypothesized) have yet to be observed over time, there is significant interest among farmers in learning “how to enhance the value of manure and its utilization for production and soil quality purposes.”

Objectives/Performance Targets

1. Demonstrate and compare five manure management strategies applied across site-specific management zones delineated on farmer fields to assess its impact on productivity and soil quality.

2. Demonstrate and compare the improvement in soil quality parameters (as measured by pH, bulk density, aggregate stability, water retention, organic matter content, electrical conductivity, and sodium adsorption ratio).

3. Demonstrate and make economic comparisons of site-specific management zone based manure management strategies to estimate differences in economic returns among the strategies.

4. Evaluate the impact of manure management strategy on water quality risk through the use of P Index and the N Leaching Index.

5. Develop a network of farmers to conduct on-farm trials and provide hands-on training via field days, farm tours, and extension workshops in the design, implementation, and analysis of field-scale farm trials using innovative site-specific management zone techniques.

Accomplishments/Milestones

As outlined in the project proposal, we started our project in October of 2006. Since then we have accomplished several things as planned in the project. They are:

We formed the project management team in fall of 2006. The management team meets periodically as per the need of the project to discuss the project plans and progress.

In early spring of 2007, we contacted the cooperating growers who provided their land and helped us in establishing demonstration studies on their farms and organizing on-farm summer field days.

We organized two hands-on workshops in cooperation with the grower organization (Colorado Conservation Tillage Association) in January of 2007 and two field days in late summer (August) of 2007. Both workshops and field-days provided an opportunity to speak to a number of growers in our region and receive their input on project plan, design, and implementation.

For 2007, we planned to establish our project work on five locations. This included two locations at the CSU ARDEC research and demonstration farm, northeast of Fort Collins, CO, and three on-farm locations, two in Brush, CO and one in Gill, CO. Two demonstration fields were soil sampled in Brush with cooperating farmer Dave Wagers, and one field was soil sampled in Gill with cooperating farmer John Larson. Following soil sampling, management zones were delineated for all the fields. While the preparation work (soil sampling and management zone delineation) was completed for demonstration fields in time, demonstration projects could not be accomplished on the two fields in Brush, CO. This was primarily because of weather conditions, i.e., unusual wet spring with intermittent snowfall in northeastern CO (till late spring of 2007) that led to the inability of the farmer to spread the manure. By the time the fields were dry, it was too late to make spring applications of manure, incorporate the manure and get the soil in shape for a favorable seedbed to attain a successful dryland corn crop. Hence the research and demonstration project was conducted only on three locations in 2007.

Over the summer months of 2007, graduate student Edwin Moshia, who is working on this project as part of his Ph.D. dissertation, initiated laboratory incubation studies to evaluate soil N mineralization potential of manure applied on soil across productivity potential management zones. [Note that although soil N mineralization study was not a part of this project, we believe that it will greatly complement the project findings in understanding the reasons behind soil N-mineralization under different manure application rates across management zones].

Crops from the demonstration fields were harvested at maturity in October/November. Data collected from crop harvest were analyzed to compare the various manure management strategies of the project. Following harvest, soil samples were acquired to assess and monitor the changes in soil quality parameters across the manure management strategies, as outlined in the project proposal. Soil analyses for soil quality parameters are being conducted in Dr. J. Davis’s (Co-PI of the project) laboratory at CSU. Soil analyses work is currently in progress.

Our plan is to conduct the research and demonstration project on 5 locations in 2008. Based on the lessons learned from 2007 and to avoid the failure (as that happened in spring 2007 due to weather conditions), the project team decided to select the demonstration fields at the cooperating farmer’s farm in fall 2007. Soil sampling was performed, management zones delineated and manure was “fall-applied” instead of “spring-applied.” The cooperating farmer was more enthused about such a manure application strategy in fall versus spring.

Preliminary data from the on-going project was presented as an oral paper at the American Society of Agronomy and Soil Science Society of America Meetings in Louisiana in November. We also presented the first-year findings of this work at the Great Plains Soil Fertility Meetings in Denver, CO in March of 2008.

Please note the progress reported above relate primarily to objectives 1 and 5, partly to objectives 2 and 4 as that involves soil sampling and monitoring over time. The objective 3 work is under progress that involves economic analyses, and the finding will be reported at a later date.

Impacts and Contributions/Outcomes

Based on the summary of evaluations from the two “hands-on workshops” and two “field days” conducted in 2007, we impacted over 65 individuals who attended the workshops and fields days. This includes farmers, crop advisors, extension agents, NRCS and EPA personnel and participants from USDA-ARS, university faculty and students. Total acres impacted as reported by the participants were 108,450 acres, out of which 55,450 acres were farmer owned and 53,000 were consulted upon. The crops impacted were forages, alfalfa, corn, wheat, sugar beets, barley, sunflower, pinto beans, safflower, and vegetables. The weighted average value of our workshop as reported by the participants was about $2.33/ac which would translate into an economic impact of over $250,000.

Collaborators: