Reakcja kukurydzy na użyźnianie gleby lekkiej wapnowanym osadem ściekowym oraz jego mieszankami z ziemią spławiakową i popiołem ze słomy

In a three-year-long experiment the reaction of potted maize grown in acid light loamy sand to a single addition of lime-treated sewage sludge, its mixtures with sugar-beet washing earth from sugar plant sediment tanks and with ash from straw burning stations was studied. Lime-treated sewage sludge from a sewage plant in Zamosc was applied in two concentrations – 2 and 5% of weight, which corresponded to 56 and 140 Mg DM ha-1, as well as in the same concentrations but with an admixture of sugar-beet washing earth from a sugar plant sediment tanks in Werbkowice (10% of weight, corresponding to 280 Mg ha-1) and ash from straw burning stations (corresponding to 0.9 Mg DM ha-1). The sewage sludge fulfilled all the requirements needed for its agricultural utilization. The maize yield three years after a single treatment with 2 and 5% addition of lime-treated sewage sludge was comparable with standard mineral fertilization applied every year to maize grown as green fodder. The proportion of cobs and the amount of N, P, Ca and Mg increased in the fodder proportionally to the applied concentration of the sludge. The additional admixture of sugar-beet washing earth from a sugar plant sediment tanks and of ash from straw burning stations enhanced the fertilizing effect of the sludge and was particularly beneficial when combined with higher, i.e. 5%, proportion of sewage sludge. The agricultural utilization of lime-treated sewage sludge is worth recommending even if its fertilizing properties do not exceed those of mineral fertilizers, because it enables not only the removal of unwanted waste, but it also helps to improve soil properties, to bring back the elements taken out from the environment and to limit the use of artificial mineral fertilizers. Combining the use of sludge with other kinds of waste additionally enhances its properties, increases its efficiency and broadens the possible range of uses