Reducing Nitrogen and Phosphorus Excretions from Dairies in Gooding and Jerome Counties, Idaho

Project Overview

Project Type: Research and Education
Funds awarded in 2002: $145,672.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $19,379.00
Region: Western
State: Idaho
Principal Investigator:
Alexander Hristov
University of Idaho

Annual Reports


  • Agronomic: barley, corn, cotton, soybeans, sugarbeets, hay
  • Animal Products: dairy


  • Animal Production: feed formulation, feed rations, manure management, mineral supplements, feed/forage
  • Education and Training: extension, on-farm/ranch research
  • Farm Business Management: agricultural finance
  • Production Systems: agroecosystems


    Nine commercial Idaho dairies (12,700 cows) were involved in all phases of this project. Nutrient flow data at farm level were collected and feeds, manure, milk, and soil samples were analyzed for various nutrients. The efficiency of whole-farm nutrient use varied greatly among participating dairies. Exporting nutrients as manure or crops, in addition to milk, was the key for achieving whole-farm balance. Levels of dietary phosphorus (P) exceeded current recommendations for high-producing dairy cows. Following our intervention, seven of the participating dairies adopted reduced P feeding, which resulted in reduced fecal P concentrations and improved the estimated farm P balance.

    Project objectives:

    1) Collect data on the nutritional (N and P) status of representative dairies in Gooding/Jerome counties. These case studies will provide the needed database on the current nutritional practices in relation to nutrient balance in an area having a high density of dairy cows.

    2) Based on current research, propose to the cooperator dairies modifications of existing nutrition practices that will result in more efficient on-farm nutrient utilization and overall reduction in N and P excretions into the environment.

    3) Monitor the results of implementing the nutritional changes on the efficiency of nutrient utilization and N and P balance in the participating dairies.

    4) Analyze the effect of the nutritional changes on the chemical properties of the manure and the economics of using manure on croplands.

    5) Estimate the radius to economically transfer accumulated manure by size of the dairy operation.

    Additional objective:

    7) Estimate whole-farm balance of K for the participating dairies.

    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.