Institute of Resource, Ecosystem and Environment of Agriculture, Nanjing Agricultural University, 1 Weigang, Nanjing, 210095, Jiangsu, China.
Jinhua Biomass Technology Institute, Jinhua Municipality, Zhejiang, 321000, China.
Environ Sci Pollut Res Int. 2019 Mar;26(9):9244-9256. doi: 10.1007/s11356-019-04417-6. Epub 2019 Feb 5.
Safe recycling of the growing amounts of municipal sewage sludge containing toxic metals had been critically challenged with the fast urbanization. In this study, we investigated soil amendment of municipal wastewater treatment (MSS) converted biochar for its recycling in agricultural soils. In a field experiment, unpyrolyzed (USS) and pyrolyzed municipal sewage sludge (PSS) was amended at 20 t ha on dry base to a rice paddy before rice plantation, with a control without amendment. Grain yield and emission of non-CO potent greenhouse gases were examined as well as topsoil metal mobility and plant uptake determined throughout a rice-wheat rotation year. Compared to USS treatment, addition of PSS caused a significantly increased grain yield of rice by 35% but no change in grain yield of wheat following the rice season. No distinct difference was observed in grain concentration of major nutrients of N, P, and K between USS and PSS treatments. Compared to USS treatment, PSS treatment reduced CH emissions by 91.6% from soil and by 78.5% from ecosystem during rice-growing season. Whereas, PSS treatment led to a reduction of ecosystem NO emissions by 70.8% relative to USS treatment during wheat-growing season. While both USS and PSS treatments slightly but insignificantly increased soil total content of heavy metals, PSS treatment reduced CaCl-extractable Cd pool by 33~40% over USS treatment. Grain contents of Cd and Pb and Cd/Zn were markedly reduced under PSS over USS, without exceeding the Chinese state guideline limit. Carbon emission intensity was considerably (by over 20%) reduced for soil and ecosystem but unchanged for wheat soil, under PSS over USS. Thus, soil amendment of pyrolyzed sewage sludge could be a measure for climate smart soil and for safe grain production in rice agriculture. It deserves further study if repeated amendment could exert sustainable impacts on soil health and food security in the paddy.
随着城市化进程的加快，大量含有毒金属的城市污水污泥的安全回收受到了严峻挑战。本研究考察了将城市污水厂（MSS）转化生物炭用于农业土壤改良的方法。在田间试验中，在水稻种植前，以干基计，将未热解的（USS）和热解的城市污水污泥（PSS）分别以 20 t ha 添加到水稻田中，同时设置不添加污泥的对照。研究了添加污泥对水稻和小麦产量以及非 CO 温室气体排放的影响，同时测定了整个水稻-小麦轮作年内土壤中重金属的移动性和植物吸收情况。与 USS 处理相比，PSS 处理使水稻产量显著增加了 35%，但对水稻季之后的小麦产量没有影响。与 USS 处理相比，PSS 处理并没有明显改变水稻中氮、磷和钾的主要养分的籽粒浓度。与 USS 处理相比，PSS 处理使水稻生长季土壤和生态系统中 CH 排放分别减少了 91.6%和 78.5%。而在小麦生长季，PSS 处理使生态系统中 NO 排放相对 USS 处理减少了 70.8%。虽然 USS 和 PSS 处理都略微但无显著增加土壤中重金属的总量，但 PSS 处理使 CaCl2 可提取 Cd 库减少了 33%至 40%。与 USS 相比，PSS 处理使水稻籽粒中的 Cd 和 Pb 以及 Cd/Zn 含量明显降低，但均未超过中国国家指导限值。与 USS 相比，PSS 处理使土壤和生态系统的碳排放量强度显著降低（超过 20%），但对小麦土壤没有影响。因此，热解污泥的土壤改良可以作为一种气候智能型土壤管理措施，用于保证水稻农业的安全粮食生产。如果重复添加能够对稻田土壤健康和粮食安全产生可持续影响，那么这种方法值得进一步研究。
