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Aim: Chicken manure is known to produce strong odors during aerobic composting, which not only pollutes the surrounding environment but also leads to the loss of valuable nutrients like nitrogen and sulfur, thus reducing the quality of the fertilizer. Methods: In this study, we explored the use of biochar combined with MgO desulfurization waste residue (MDWR) as a novel composting additive. Our approach involved conducting composting tests, characterizing the compost samples, conducting pot experiments, and examining the impact of the additives on nitrogen retention, deodorization, and compost quality. Results: Our findings revealed that the addition of biochar and MDWR significantly reduced ammonia volatilization in chicken manure compost, demonstrating a reduction rate of up to 60.12%. Additionally, the emission of volatile organic compounds (VOCs) from chicken manure compost treated with biochar and MDWR decreased by 44.63% compared to the control group. Conclusions: The composting product treated with both biochar and MDWR (CMB) exhibited a 67.7% increase in total nitrogen (TN) compared to the blank control group, surpassing the other treatment groups and showcasing the synergistic effect of these two additives on nitrogen retention. Moreover, the CMB treatment facilitated the formation of struvite crystals. Furthermore, our pot experiment results demonstrated that the CMB treatment enhanced vegetable yield and quality while reducing nitrate content. These findings highlight the significant impact of MDWR on nitrogen retention, deodorization, and compost quality enhancement, thereby indicating its promising application prospects. [ABSTRACT FROM AUTHOR]

Zinc lignosulfonate (Zn-LS) is a kind of organic fertilizers made from the by-products of paper industry. With leach and plot treatments, this paper studied the difference of the biological availability between Zn-LS and an inorganic Zn-fertilizer on calcareous soil of north Guangdong Province. The results indicated that the Zn of Zn-LS was less absorbed by calcareous soil. In soil B, when applying 10 mg x kg(-1) Zn, the dissolved amount of Zn-LS was 65.2% higher than that of inorganic Zn-fertilizer, corn grew well, and its biomass was higher. In soil A, when applying 10 mg x kg(-1) Zn of Zn-LS, the biomass of corn increased by 16.3%, and its Zn content was 81.2% higher. Therefore, biological availability of Zn-LS was better than that of inorganic Zn fertilizer.

Indoor cultivation experiment and plot field experiment were conducted to study the effect of lignosulfonates on urea nitrogen transformation in soil and the mechanism of controlling nitrate pollution in vegetable. Results showed that lignosulfonates behaved inhibition effect on urea hydrolysis compared with the contrast treatment, the contents of remainder urea nitrogen treated with lignosulfonates was more than that of another kind of urease inhibitor hydroquinone in soil after 69 hours' cultivation. Lignosulfonates could reduce contents of nitrate in cabbage, it as well increase contents of vitamin C in a large degree, enhance the nitrate reductase activity, then accelerated nitrogen assimilation in plants. The urease activity was lower and contents of ammonium nitrogen in soil was larger after ingathering, lignosulfonates could keep nitrogen release slowly, and could be used as a kind of effective inhibitor to nitrogen fertilizer in the controlled-release fertilizers.

The effects of several chemical-biological combined decomposing techniques (CBCDT) on the decomposition of rice straw were studied by fourier transform infrared spectroscopy (FTIR). The results showed that under CBCDT treatments, rice straw could be better decomposed than in control. After seven days under CBCDT treatments, the straw turned into brown, and was easy to be broken down and obviously decomposed. FTIR spectra indicated that under chemical agent A-biological agent A combined treatment, hydroxyl, ketonic carbonyl, methyl, methylene, methane and aliphatic compounds decreased, proteins and amino acids completely decomposed, but aromatic compounds (specially substituted group) increased, and hence, the humification of straw was accelerated. The effects of different decomposing agents on straw were decreased in the order of chemical degrade agent A > chemical degrade agent B, biological degrade agent A > biological degrade agent B > biological degrade agent C. The chemical agent A-biological agent A combined treatment was the most effective among several treatments.