by Bob Buchanan, Alberta Agriculture, Barrhead, Alberta
Over the past three years, the Zoology Department of the University of Alberta and Regional Agricultural Engineering Technologists from Alberta Agriculture have been working on a joint project to improve water quality in farm dugouts. The project is an excellent example of how research and extension specialists can work together. Over the three years the project has moved quickly from research in 1988, to on-farm demonstrations in 1989 and to province wide acceptance in 1990. Initially, the liming project focused on algae control but the treatment controls a much broader spectrum of dugout water problems.Liming involves the use of hydrated lime (calcium hydroxide) to settle out algae, phosphorus, sediment and some colour from the water The hydrated lime is mixed with water and sprayed evenly across the dugout surface. The attached sketch shows a typical dugout liming system. Dugouts will require from about 500 to 2000 pounds of hydrated lime. The proper dosage is determined by measuring the dugout volume and testing the alkalinity level of the water. Hydrated lime will cause temporary increases in the pH of the water. Although there are no direct health concerns with high pH (10), it is recommended that the water not be used for livestock, poultry and human consumption until the lime settles. Generally the lime will settle out completely in 3 to 10 days after the treatment.
Hydrated lime is a very corrosive chemical Safety equipment must be worn while handling to protect skin and eyes from chemical burns. The liming treatment cannot be used on dugouts stocked with fish, or fishkill will result. In Alberta most farm dugouts are lime treated by custom applicators. Most custom applicators have all the necessary equipment for water testing, safe handling and applying the hydrated lime.
In 1990, over 700 farm dugouts across Alberta were treated with hydrated lime. The number of custom applicators has grown to 15 in 1990. The costs of a custom lime treatment ranged from $200 to $500 per dugout. The hydrated lime treatment showed dramatic results in some heavy duty dugouts in the Spirit River - Rycroft areas even after heavy rains in June turned the dugouts to mud soup. Over 90% of farmers were very happy with the improvement in dugout water quality following the hydrated lime treatment. Dugouts treated in 1988 and 1989 showed improvement in water quality for one to two years after treatment.
Although the dugout liming treatment has been very successful in improving dugout water quality in Alberta the treatment has not yet been proven Saskatchewan and Manitoba. Further investigation is required.
It is important to realize that dugout water quality is extremely variable across the prairies and from one farm to the next. Dugout water quality is affected by soil conditions, dugout depth and shape, the type of agriculture runoff and plant and algae growth. There are many dugout management practices available for improving water quality such as algae and weed control, liming, aeration, bank erosion protection, grassed waterways and runoff controls to allow only good water quality to enter the dugout. All of these management techniques are important. Dugout liming is just one management tool.
In Alberta further work is underway to determine the effectiveness and feasibility of the hydrated lime treatment for controlling rooted dugout plants, colour removal and softening of dugout water.