Project Introduction

The primary research objective throughout this program has been to develop methods that farmers can use (or contract out) to document the impact of grazing by geese on crop yield. We have worked with wheat and grass seed crops but believe that our techniques are adaptable for other crops.

Yield is affected by many factors within a field. It is therefore important that factors influencing yield are identified by location within the field and adequately measured. For example, it is important to accurately map areas that are damaged by standing water or flooding. In some cases the factors affecting yield may interact with each other. Soil parameters and fertility affect crop productivity and lead to variation in crop growth and yield across a field. Thus, farm fields are characterized by areas with varying potential to produce crop output. Across a given field, one could find variability with respect to soil type, nutrient status, landscape position, organic matter content, water holding capacity, and so on. Because variation in these factors leads to fluctuation in yield, we need to record and map as many variables as possible. In order to analyze goose grazing impacts from other factors, grazing exclosures are added to a field. In this case all other factors are similar (fertilization, soil classification, topography, farming techniques, etc.) and the differences are the result of goose grazing. Separating goose grazing from other factors that influence yield is critical for ensuring good results. We think that frequent field visits are prerequisite to a well-executed study. It is important to map where, when, and how intensely geese graze.

The integration of geographical information systems (GIS), ground-truth data collection via geo-positioning (DGPS), platform photography with selected measurements, and yield-mapping systems provides the tools to document impacts of wild geese on grain and seed crops. This combination of tools is effective in documenting, quantifying, and spatially delineating wild goose grazing impacts. We believe the methodology presented in this manual is relevant to the broader agricultural community. This approach should provide farmers and wildlife agency personnel with reliable information as they work together to evaluate goose impacts.


This manual provides protocols and methods to quantify and statistically analyze goose-grazing impacts on field crops. The manual is divided into three parts and each part has two sections.

The first part describes procedures that growers can follow, with or without technical assistance. These procedures include setting up goose-proof exclosures as outlined in Section A. Section B describes how to perform the ground truthing and monitoring of goose activity. Other impacts are also recorded during field visits, such as water damage, deer/elk grazing, etc. Areas are mapped and delineated with a hand-held GPS unit.

The second part describes procedures that typically will be provided by a technical assistance provider with computer skills - particularly GIS (Geographical Information Systems) applications. Procedures described in this section include building base maps, developing various GIS data layers (goose grazing, soil type, water impacts), and analyzing yield data. Data analysis is discussed in section A, which also includes a discussion of how base maps are created. Section B describes how a GPS works, compares different types of GPS, and identifies what information should be collected.

The third part covers key recommendations that the growers and service providers should carefully follow to improve the likelihood that quality data will be collected. There are pitfalls that can be avoided easily with proper planning. Section A highlights some major areas that require special attention to ensure that reliable information is collected, processed, and analyzed. In section B we included step-by-step instructions on how to construct a camera platform that facilitates vertical photography for monitoring plant growth, cover, and development.

Altogether, this manual provides growers, conservation professionals, and farm-service businesses with a comprehensive methodology to quantify goose impacts that includes step-by-step instructions, supplementary information, and pictures.
This information is compiled on the enclosed CD-ROM as of November 30, 2003 and at one central web site (http://www.oregonstate.edu/dept/range/gooseproject) for easy retrieval and recently updated information.

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