Use of Domestic Geese to Control Weeds for Agriculture and Forestry Applications in Alaska

Use of Domestic Geese to Control Weeds for Agriculture and Forestry Applications in Alaska

Summary

Weed control is a major problem and expense for Alaskan growers. For lack of alternatives, most Alaskan farmers and nurserymen use herbicides or hand control. We are studying an alternative method of weed control, the use of weeder geese. Domestic geese are voracious herbivores and prefer many plant species that are also noxious weeds. When released into fields of crops that they find unpalatable, domestic geese can be an effective, economical and ecologically sound method of weed control.

The idea of using domestic geese to weed crops is not new. Before the development of the first organic herbicides in the 1940s, 200,000 geese controlled weeds in the cotton fields of California's San Joaquin Valley. They have been used in such crops as berries, potatoes, carrots and onions, and are used today in commercial mint production in the Pacific Northwest. We feel that weeder geese have the potential to control weeds in a large variety of important crops. Particularly where herbicide use is problematic, weeder geese may be more economical than other forms of weed control. Lack of information about the challenges and potential positive outcomes of such an approach may be the primary factor limiting their use.

At northern latitudes, cold soil temperatures slow the breakdown of agricultural chemicals. Herbicides degrade much slower in such areas than they do in temperate climates. This slow break-down leads to problems with crop rotation, inhibiting the growth of crops in subsequent years and increasing the risk of chemicals leaching into ground water. This ACE research project conducted the first controlled investigation of the use of domestic geese compared with herbicides to control weeds in an interior Alaska Christmas tree plantation. We also conducted two on-farm trials to find out how farmers felt about using geese for weed control in other crops.

Objectives

Overall objectives for the two-year study are:

(1) To determine whether geese effectively control common agricultural weeds without damaging crops.

(2) To compare the cost and efficacy of four different methods of weed control (geese, hand-control, geese-with-supplemental-hand-control, and herbicides).

(3) To determine the impact of weeder geese on soil chemistry and water quality, with special attention to the increased nitrogen loads expected in geese-weeded areas.

(4) To compare the growth rates of weed-fed geese with geese subjected to more conventional pen raised/grain feeding practices.

Annual Progress Report for 1992

The study began in 1992. Highlights from first-year results follow.

Domestic geese were effective weed-control agents: crop growth in the goose-weeded plots was equal to that in the herbicide-weeded plots, and significantly greater than in the unweeded plots.

Geese did not cause soil compaction, as has been suggested in other literature. By returning weedy plant material to the soil in the form of nutrient-rich feces, geese reduced the crop's need for supplemental fertilizer.

Trampling by geese caused significant crop mortality among trees less than three years old. Changes in cultural practices (such as not using geese in plantations until the second or third year of tree growth) would prevent this.

Weed populations in the goose-weeded plots shifted toward species the geese found unpalatable. Thus, a combination of weed-control methods is advised. Weeder geese are likely to reduce rather than replace the use of herbicides.

Farmers in the farm trials found that:

Timing of geese introductions to potatoes is crucial. Geese will eat very young potato plants but will not touch older plants.

The geese were ineffective in raspberries and were most effective in strawberries. Trampling was a problem in carrots and lettuce.

The geese did not eat pineapple weed (Matricaria matricarioides); because this weed is a major problem in this area, supplemental weed control of this species was necessary.

Geese need to be herded around farm fields, increasing labor costs.

In the second year of our project, 1993, we will test ways of limiting crop trampling problems. We will analyze the cost of several weed control methods, including hand control by hoeing. And, we will document the fate of the herbicide Velpar in our herbicide-treated plots.