The application of biochar to screen printing liquid waste polluted land, its effect in soil, mustard greens to heavy metals (Fe, Cr)

Purpose The purpose of this paper is to analyse the screen printing liquid waste polluted soil physical, chemical and biological characteristics, with the unpolluted soil, and to analyse the application of some types of biochar towards the growth of mustard greens plants and the concentration of heavy metals Fe, Cr on the screen printing liquid waste polluted soil. Design/methodology/approach This research was conducted in a green house by using fully randomized design, split plot design pattern, with three replications. The main plot is the type of biochar, and the subplot is the dosage of biochar. The biochar consists of four types (B1 = chicken manure biochar, B2 = coconut shell biochar, B3 = rice hulls biochar and B4 = mahogany woods biochar). The dosage of biochar consists of four levels (D0 = control, D1 = 5 ton/hectare, D2 = 10 ton/hectare and D3 = 15 ton/hectare). The tested variable is being analysed by using analysis of variance (ANOVA). Findings The screen printing liquid waste polluted soil physical, chemical and biological characteristics analysis shows that the soil pH is neutral, a low C organic, a low N total, a high P, CEC and base saturation, while the texture is soft. The analysis results of rice hulls biochar physical, chemical and biological characteristics are quantitatively better in comparison with chicken manure biochar, coconut shell biochar and mahogany biochar. The quantitative application of rice hulls biochar15 ton/hectare dosage can increase the growth of mustard greens, and also, it recovers the soil characteristics by heavy metals total rate of 14.11 ppm Fe and 0.95 ppm Cr from the plant, while 209.05 ppm Fe and 4.12 ppm Cr were found in the soil. Originality/value This is one of few studies the biochar to screen printing liquid waste polluted lands. Currently, numerous kinds of chemical substances have been applied in a form of fertilizer and pesticide into the soil. Other activities like transporting the crop residues, and the contamination of irrigation water that is caused by screen printing liquid waste, have also affected the soil. It becomes degraded where the soil becomes compact and losses its nutrients, and it is containing heavy metals material that is toxic for plants. Biochar is applied into the polluted soil to improve the soil, which is hard to decompose and is long-lasting in the soil. These days, both the raw or ready food products are exposed to the heavy metals with a large and concerning number, especially in big cities which most of the soil is polluted.