Influence of farm compost on soil quality and crop yields

Intensification of agriculture was attended with an increased productivity and efficiency leading to significant increases in food production. However agricultural intensification can have negative consequences such as increased erosion, lower soil fertility, reduced biodiversity and a reduction in soil organic matter (SOM) content resulting in an inevitable decline in the quality of agricultural soils. The application of compost can contribute to agricultural sustainability as continuous and adequate use of compost with proper management has been shown to have many advantages. Most of the research on compost done so far, has focused on the use of municipal solid waste compost. Farm compost is another type of compost. It is made of ingredients which are available on the farm like wood chips and bark, manure, slurry, straw, crop residues, mowed grass and soil. The use of farm compost is popular in organic farming and there is a growing interest to use it in non-organic farming. However, there is a lack of information on the agronomic value and environmental impact of farm compost. Therefore, the aim of this study was to assess the influence of repeated farm compost applications on crop yields and soil quality. The research was done on a pre-established trial site. The experiment started in 2004 and combines a crop rotation of potatoes, fodder beet, forage maize and Brussels sprout with the addition of farm compost. The rotation takes four years and every crop is grown every year. While evaluating the soil quality, it is important to integrate physical, chemical and biological indicators since the correct functioning of a soil depends on an immense number of physical, chemical and biological properties. In this present research, soil bulk density (physical), total organic carbon and hot-water extractable carbon (chemical) and earthworms, microbial biomass-C and nematodes (biological) were used as indicators to determine soil quality.
Repeated applications of farm compost increased soil organic carbon content, hot-water extractable carbon, earthworm numbers, microbial biomass-C and reduced soil bulk density. Our results confirm the potential benefits of farm compost application for soil quality by improving the physical, chemical and biological properties of the soils. Furthermore the effect of farm compost on crop yields became significant for all crops after the fourth year of compost application underscoring the ability of compost amendments to support crop yields over time.


Key Words: farm compost, indicators of soil quality, crop yields, long term field experiment