A Four-Year Study on Influence of Biosolids/MSW Cocompost Application in Less Productive Soils In Alberta: Nutrient Dynamics

Compost Science & Utilization, (2006), Vol. 14, No. 1, 68-80

M. Zhang (1), D. Heaney (2), B. Henriquez (3), E. Solberg (4) and E. Bittner (5)

1. Department of Plant, Animal and Soil Sciences, School of Natural Resources
and Agricultural Science, University of Alaska Fairbanks, Alaska
2. Norwest Labs, Edmonton, Alberta, Canada
3. Crop Diversification Centre North, Alberta Agriculture, Food and Rural Development,
Edmonton, Alberta, Canada
4. Sun Mountain Inc., Alberta, Canada
5. Drainage Branch, City of Edmonton, Gold Bar Wastewater Treatment Plant,
Edmonton, Alberta, Canada

Composting municipal solid waste and biosolids and applying it on arable land have become an alternative way to treat waste in large municipalities in North America. However, cost of compost transportation and application constrains the compost use on the land further away from where it is produced. A four-year experiment was conducted (1998-2001) in less productive soils in Alberta to determine the effect of once in four year application of cocompost on soil nutrient dynamics and crop N uptakes. There were three crop blocks: barley (Hordeum vulgare L.), wheat (Triticum aestivum L), and canola (Brassica rapa), and they were rotated annually. The compost was only applied in 1998 at a rate of 50, 100 and 200 t/ha. Soil samples were taken in spring of every year after initial compost application to determine extractable N, P, K, S, Cu, Zn, Soil pH and EC. Each year, crops were harvested and N uptake was determined. Total concentrations of an array of heavy metals in the first year and fourth year after compost application were determined as well. The results showed that the release of N from the compost was high in the first year after compost application and then declined in each subsequent year. Similar to that release pattern was sulphur. The release of phosphorus from compost was steady throughout the four-year experimental time. Crop N uptake from compost application varied with crops and sites. The over all N use efficiency for three crops and two sites was 11%, 3%, 1% and 2% for the first and subsequent three years. The total heavy metal concentrations in the compost amended soils in the first and fourth year after compost application were similar, and they were below the standard of Canadian Fertilizer Act. Our results showed that N released from compost occurred mostly in the first two years after application, suggesting that an application frequency of once in every second year may be better than the once in every four year application strategy, especially with 100 t/ha application rate.

Copyright 2007, The JG Press, Inc.