engleski

Effects of biochar and sugar factory lime application on soil pH in acidic soils

Soil reaction, expressed as a pH value, is an indicator of acidity or alkalinity of soil and can strongly influence physical, chemical and biological processes in soil, plant nutrition and fertilizer efficiency. Furthermore, the soil acidic reaction causes increased mobility of aluminium in the soil. If toxic concentrations of aluminium are reached, they will have negative effects on root growth, i.e. decreased growth and development of the whole plant. Plants can grow and develop in soils of different soil reactions, but the optimum reaction is between slightly alkaline and slightly acidic. The aim of this research was to determine the differences between the effects of biochar and sugar factory waste lime on soil reaction in acid soils. Currently mostly used soil conditioner for acid soils in Croatia is sugar factory waste lime, which is a by-product from the production of sugar and contains 30% Ca. Biochar is the product obtained through the pyrolysis of waste biomass. In agriculture, it is used as soil conditioner and can have positive effects on several physical, chemical and biological soil properties. The research was carried out on stationary field trials at two locations on acid soils in Osijek- Baranja, and Virovitica- Podravina County, Croatia. Experimental design was a split-plot with four repetitions and the crop used was corn. Biochar was the main factor which was compared to liming with sugar factory waste lime. The treatment were: C - control, B1 - 5 t ha-1, B2 - 10 t ha-1, B3 - 15 t ha-1 of biochar and L1 optimal dose of sugar factory waste lime that was calculated for each field trial location. Two steps of sub factors were also applied, F0 - without fertilization and F1 – with recommended fertilization. Soil samples were taken in V3 and silking stages of corn growth. Initial soil analysis revealed a strongly acidic soil reaction at the location Osijek-Baranja (pH 5.12) and very strongly acidic reaction at location Virovitica- Podravina (pH 5.0). The average soil pH value in V3 stage of corn growth was 5.42 and was under a very significant influence of soil conditioner and fertilization treatment. The highest pH values were measured in treatment with liming and compared to other treatments the differences were at 99% significance. The average pH value in silking was 5.93 and its variation was under significant influence of soil conditioner treatment. Again, the highest soil pH values were measured in soil samples with liming and non- fertilized soil samples had a higher pH value than soil samples where fertilization was applied (99% significance). Also, in the silking on both locations, significantly higher soil pH value was measured in treatment B3 (95% significance) compared to C, B1 and B2 treatment, indicating a positive effect of biochar on soil reaction. The most common soil conditioning measure conducted on acid soils is liming, which has already been proven to be the fastest way to raise soil pH. This statement was confirmed by this research, but it must be noted that together with liming we usually must implement many other different soil restauration measures like humization especially in degraded soils. It can be concluded that biochar, is a powerful soil enhancer that positively affects several important physical, chemical and biological soil properties, and it can be easily used as soil conditioner for acid soils, especially if we consider its prolonged action in soil.

biochar ; sugar factory waste lime ; acid soil ; soil restauration measures ; soil reaction

nije evidentirano