EFFECT OF SEWAGE SLUDGE COMPOST TREATMENT ON CROP YIELD

Abstract

Due to the increasing number of sewage cleaning plants, the amount of sewage
sludge also increases. We have to solve the environmentally sound disposal of the
sludge. Results of many experiments show that sewage sludge and sewage sludge
compost can be recycled as nutrient suppling material in agriculture. Municipal
sewage sludge compost could cause the occurrence and accumulation of toxic
elements in the soil. A small-plot experiment with sewage sludge compost was
established in the spring of 2003. The applied compost contains 40% sewage
sludge, 25% straw, 30% rhyolite, 5% betonite. The small-plot experiment was retreated
in the autumn of 2006, 2009, 2012and 2015. There are 4 treatments in five
blocks, where the sewage sludge compost was applied at a rate of 0, 9, 18 and 27
tha-1 and then ploughed into the soil. Triticale as autumn cereal, maize and green
pea as spring crops were sown in crop rotation every year. Plant samples were
collected before harvesting. In this paper the results of crop yield between 2010-
2012 are presented. Crops of triticale and maize were higher in the treated plots
than in control one in 2010 and 2011. Treatment effect was not observed on green
pea yield.The results show that the effect of applied compost doses depends on
plant species and time. Our aim is to maintain this unique long-term experiment for
studying the composted sewage sludge as a nutrient and organic matter source,
applying it similarly to the farmyard manure.