Site-specific Manure Management for Improving Soil Quality

Project Overview

Project Type: Research and Education
Funds awarded in 2006: $131,332.00
Projected End Date: 12/31/2010
Region: Western
State: Colorado
Principal Investigator:
Dr. Raj Khosla
Colorado State University

Annual Reports


  • Agronomic: corn


  • Animal Production: manure management
  • Crop Production: conservation tillage
  • Production Systems: agroecosystems, holistic management
  • Soil Management: organic matter, soil analysis, soil quality/health

    Proposal abstract:

    An innovative approach called “Site-Specific Management Zones” classifies farm fields into productivity level management zones (high, medium and low). Past research has clearly shown that variable rate fertilizer application using management zones, i.e., applying higher rates of fertilizer on high management zones and lower rates on low management zones, results in overall increases in grain yield, net $ returns and reduction in environmentally-sensitive nutrient loads into soil.

    The above approach, although scientifically logical, has faced resistance from farmers in adoption. Farmer concern is that the approach recognizes variability in productivity potential; however it does nothing to improve the yield-limiting factors of low and medium management zones to enhance grain yields of those areas.

    Farmers have hypothesized that application of higher levels of manure on poor producing areas over time will enhance soil quality, water holding capacity, organic matter, other soil properties, and will enhance grain yield and net $ return of such areas. If the above
    approach, as suggested by farmers, works it creates an economically sound method of disposing manure for enhancing soil quality and sustaining productivity. However, no data currently exist that provide recommendations on how much and when to apply manure on
    respective management zones.

    We have designed a three-year project to research, educate and extend the utility of the site-specific management zone technique to manure management strategies. Expected outcomes include increased knowledge, change in attitude and improved skills in site-specific
    manure management. Long-term goals include enhanced soil quality and grain yield, improved sustainability of crop production systems and protected water quality.

    Project objectives from proposal:


    The overall objective of this project is to research, educate and extend the utility of the site-specific management zone technique to manure application strategies. These strategies will be compatible with farming practices in the western Great Plains.

    Specific objectives are: [Individual(s) responsible for each objective are listed in brackets]

    1. Demonstrate and compare five manure management strategies applied across site-specific management zones delineated on farmers' fields to assess their impact on productivity and soil quality. [Khosla and Davis]

    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). [Petersen and Davis]

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

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

    5. Develop a network of farmers to conduct on-farm trials, 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. [Khosla, Davis, and Bosley]

    Successful attainment of objectives above will lead to overall project goals, i.e., to enhance soil quality and grain yield, reduce soil erosion potential, improve sustainability of crop production systems and protect water quality.

    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.