The Effect of Biochar Derived from Municipal Pruning Wastes at Different Pyrolysis Temperatures on Maize Growth and Soil Chemical and Microbial Properties
Project no. 21328 · Status: Kapanmış · 2019
Summary
Increasing energy costs, greenhouse gas emissions and concerns about the non-recyclable nature of fossil fuels have led to significant research in the conversion of biomass to biofuels and other value-added renewable products. Pyrolysis, one of the processes that stand out among biomass conversion technologies, is a relatively simple technique in which organic material is heated in the absence of oxygen. The research was conducted as a pot study at Ege University Faculty of Agriculture Soil Science and Plant Nutrition Department's experimental greenhouse in 2020. The pot experiment was set up in a randomized plot design with three replications (n = 45). Biochar was obtained at three different pyrolysis temperatures (300, 500, 700 °C) from municipal pruning waste. The effects of biochar treatments at a rate of 0, 10, 20, 30 and 60 t ha-1on some biological (soil respiration, dehydrogenase activity) and chemical properties (pH, electrical conductivity-EC, organic carbon, cation exchange capacity-KDK, N as total, P, K, Ca, Mg, Na, Fe, Cu, Zn, Mn and B as available), as well as maize yield (fresh plant biomass), were investigated. According to the statistical analysis of the data obtained from the pot experiment results; statistically significant effects of "PYROLYSIS TEMPERATURE", "TREATMENT" and "PYROLYSIS TEMPERATURE x TREATMENT" factors on dependent variables were determined (P<0.01). Depending on the biochar applications, the parameters examined showed significant changes between -48% and 141% when compared with the control soils (P<0.05). The effect of biochar applications obtained at different pyrolysis temperatures on dependent variables showed statistically significant differences. It has been determined that biochar obtained at 300 °C pyrolysis temperature can be biodegraded more easily than biochar obtained at 500 and 700 °C. Therefore, biochar obtained at 300 °C pyrolysis temperature has made the most positive contribution regarding microbial activity, and its doses of 20, 30 and 60 t ha-1 can be recommended. Similarly, available phosphorus and boron anions showed the most positive effect from biochar applications at 300 °C pyrolysis temperature. Moreover, with the application of 60 t ha-1, the available boron concentration achieved the highest increase. Although it varies according to the raw material obtained from biochar, it has been determined that biochar with high pH has the potential to increase the pH value of soils by 0.5-6.2% in 75 days. This situation is considered as an important result in the improvement of acidic soils. The decrease in EC value, which is an indicator of soil salinity, with 700 °C and 20, 30 and 60 t ha-1 treatments, is an important result for the improvement of saline soils. The potential to increase CEC, which is a parameter significantly affected by all biochar doses, has been obtained by 31.3%. No effect of independent variables on soil Mn, Fe and Cu was found. In the yield parameter, an increase of 71.4% was determined at a rate of 60 t ha-1 of 700 °C. Biochar, which is an organic soil amendment, has different effects at different pyrolysis temperatures and application doses. Therefore, it may be recommended to determine the pyrolysis temperatures and application doses depending on the properties of the soil to be improved and supported. In addition, it is considered important to ensure that biochar can be included in the "Regulation on Organic, Mineral and Microbial Origin Fertilizers Used in Agriculture".