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The aim of the study was to assess the physiological status of Brassica seedlings grown in two types of soils following a single application of smoke water (SW). One soil was contaminated with heavy metals from a local smelter, and another was sandy and poor in nutrients. Three-week monitoring indicated that soil composition was the primary factor affecting chlorophyll fluorescence (CF) parameters, growth, and development of seedlings, and the contaminants affected the plants more than the lack of nutrients. SW aggravated the negative impact of heavy metals, which became visible when the plants transiently suffered from the heavy metal exposure. Most of CF parameters changed suddenly but then the trend reversed indicating that plants gradually adapted to the specific conditions. However, this was not reflected in the final biomass of the seedlings. This might be due to redirection of photosynthates towards protective mechanisms against toxic effects of metals.

Due to the fact that soils in Poland are mostly light soils, there is a need to improve their physical, chemical and biological properties. In addition, as a result of the decrease in the number of farm animals, a decrease in production of natural fertilizers can be observed. Low production of natural fertilizers speaks in favor of agricultural use of municipal sewage sludge in Poland. Municipal sewage sludge is composed of large quantities of macronutrients necessary for plants. This waste also contains significant amounts of organic substance. Chemical properties, including a high content of nitrogen, phosphorus, and often calcium, speak in favor of environmental use of municipal sewage sludge. Increasing requirements with respect to environmental protection cause the necessity to assess the effects of using organic waste for fertilization. In a farm located in the commune of Iwanowice (Małopolska province), municipal sewage sludge was applied under spring barley cultivation. The soil on which municipal sewage sludge was applied was classified into the category of heavy soils with neutral reaction. When assessing the content of available nutrients (P, K, Mg) in the soil, their low content was determined. After application of municipal sewage sludge in a dose of 24 Mg fresh matter per hectare, which corresponded to 5.34 Mg DM·ha−1, under spring barley, beneficial changes in chemical properties of the soil were observed. An increase in soil abundance in organic carbon and total nitrogen was observed, as well as an increase in the content of available forms of phosphorus, potassium and magnesium. Based on the results of the conducted chemical analyses, it was established that biomass of spring barley fertilized with sewage sludge contained more macronutrients (N, P, K, Na, Ca and Mg), which improved its feed value. The field experiment showed that application of municipal sewage sludge increased uptake of macronutrients by spring barley.

Municipal sewage sludge contains considerable amounts of macro and microelements essential for plant nutrition. With decreasing use of natural and organic fertilizers, there is a need to search for alternative sources of organic matter (which is a substrate for humus reproduction). In a field experiment carried out on heavy soil with neutral reaction, the effect of single application of municipal sewage sludge in a dose of 5.34 Mg⋅ha -1 DM was compared to an equivalent dose of mineral fertilizers. The test plant was spring barley. After application of municipal sewage sludge, slight positive changes in the chemical properties of the soil were observed. The sewage sludge increased the yield of spring barley grain and straw by, respectively, 14 and 13% in relation to treatment with mineral fertilization. Spring barley fertilized with sewage sludge contained more elements than barley grown only on mineral fertilizers. It was shown that application of municipal sewage sludge to the soil had a significant effect on increase in nutrient uptake by spring barley. Fe was taken up in the highest amount, followed by Al and Mn, and Co was taken up in the smallest amounts. Utilization of Fe, Mn, Co and Al from sewage sludge by spring barley was at 6.0, 4.7, 0.7 and 0.7%, respectively of the amount applied to the soil with this waste. The mass ratios (Fe:Mn, Fe:Al, Mn:Co) analyzed in spring barley biomass were much wider in straw than in grain. In terms of grain feed value, Fe:Mn ratio in grain and straw was greater than optimum.

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