Develop a Decision Support System for Land Application of Manure Affecting the Groundwater Quality in Manitoba

Project: MLMMI 99-02-03

Objective

Develop a computer based Decision Support System to calculate the available nutrients to plant growth.

Performer

R. Sri Rarkjan
University of Manitoba

Details

Status: Completed
Started: 2000-01-04
Completed: 2001-12-11

Funding Partners: who have contributed to MLMMI in support of this project:
Manitoba Pork Council and industry groups - $29,250

Amount Funded: $29,250.00
Performer Funded: $10,000.00
Total Cost: $39,250.00

Activity

First Interim Report due July 4/00.
Reporting dates changed to Aug 4/00, Feb 4/01 and Aug 4/01.
Interim report received Aug 4/00 and Feb 21 /01.
Final report due July 4, 2001.
Request for extension to Dec 4/01 received and granted.
Final Report Received Dec 11, 2001.

Summary

Traditionally, livestock operations have remained as part of a mixed-farming operation closely integrating the feed production and manure disposal within the farm. With the expansion of the livestock industry, newer operations of 2500 sow farrow-to-weaner and 6,000 hog finishing operations have become more popular due to the economies of scale. As the operations become larger, the increasing volume of manure generated within a small area requires a larger area for land disposal. However, if the nutrient value of manure can be demonstrated then the manure will become a valuable resource rather than a waste that needs disposal.

The Sustain2 computer simulation model is a decision support system (DSS) that is designed to show the economic and environmental impact of land application of manure for a given soil, crop, and weather combination. The Sustain2 model follows the on-farm nitrogen cycle from feed to nitrogen excretion, N losses during collection, storage, spreading, nitrogen conversions in the soil, crop uptake, and eventual leaching of any remainder to the groundwater. Different management practices such as application rate, time and frequency of application, and different forms of nitrogen in manure are used as input and the impact is simulated over a five-year period. The nitrogen in manure has to mineralize to an inorganic form before it can be taken up by the plant as a nutrient. When nitrogen is mineralized to the nitrate form, it becomes highly water soluble facilitating easy uptake by plants. However, the high solubility also leads to increased leaching of nitrates beneath the root zone. By balancing the amount of water applied to the crop with crop water needs, the amount of water leaching beneath the root zone could be controlled. This can minimize the quantity of nitrates moving beneath the root zone and protect the ground water quality in the long term.

The Sustain2 model provides output showing the distribution of nitrate and water content within the root zone as a function of time. It also shows the quantity of nitrate leaching beneath the root zone. The Sustain2 model can be used to assess the impact of different dates of manure application as well as application rates. The Sustain2 Model output, presented below, shows distribution of nitrate in the root zone “before” and “after” adopting a best manure management plan. The accumulation of nitrate within the root zone is reduced after the adoption of the best management plan. The model provides the ability to simulate the impact of alternative manure management plans.

Documents

Full Report

Manitoba Pork represents 624 Manitoba hog farms