engleski

The effect of sewage sludge and sludge compost on soil fertility, organic matter content and yield of perennial ryegrass (Lolium perenne)

The effect of anaerobically stabilized sewage sludge and sludge compost on the chemical properties, organic matter (OM) content and quality, and macro- nutrient amounts of acidic sand and calcareous chernozem soils was studied. The impact on the yield and nutrient uptake of perennial ryegrass test plant was also evaluated. The amendments were added to the soils in a proportion of 1 % and 3 % rates. The composting process and the compost additive (green waste) increased the pH and decreased the organic carbon and nitrogen contents of the sewage sludge. The pH of the acidic soil was increased especially by compost treatments, while the sewage sludge application lowered the pH of the calcareous chernozem from the alkaline range to near neutral. The OM and dissolved organic carbon (DOC) showed moderate, total N slight, while NH4-N, NO3-N and P substantial increases as a result of the applied treatments. Biomass yields followed a similar trend on both soils: sewage sludge amendment showed a strong effect even at the 1 % treatment rate while increasing the compost addition to soil led to a more gradual growth of ryegrass yields. As a result of the studied treatments, the plant N contents also increased in some cases.

sewage sludge ; compost ; organic matter quality ; perennial ryegrass

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