Comparison of the Effects of Some Organic Compounds and Their Biochar on Some Soil Properties

Nowadays, recycling of organic wastes produced in food and medicinal factories by applying them to agricultural lands as organic fertilizers is the focus of attention. The present study was carried out to compare the effect of applying organic wastes of four factories in Fars and Khuzestan provinces and their biochars on some of the chemical properties of a calcareous soil. An experiment was conducted for two months in a completely randomized design based on a factorial arrangement (9 × 4), including 9 organic waste types (filter cake, bagasse, bagasse-biochar, sugar beet, sugar beet-biochar, licorice, licorice-biochar, soybean meal and soybean meal-biochar) at 4 rates of application (0, 1%, 2% and 3% by weight) with three replications. The results showed that interaction effects of organic waste types and rates, on the soil available phosphorus (P), soil DTPA-extractable iron (Fe), copper (Cu) and manganese (Mn) concentrations and electrical conductivity (EC) were significant. The soil amended with soybean meal had the highest nitrogen (N) and Cu content. Filter cake was a good source for P, zinc (Zn) and Fe and sugar beet pulp was a good source for Mn. There was no significant difference in the amounts of available nutrients between raw organic materials and their biochars. Although the increase in the level of application of these wastes by two to three percent by weight increased the accessibility of these elements, the application of higher levels of these wastes was accompanied by 33% to 166% increase in soil electrical conductivity; so, widespread use of these wastes should be done more cautiously.