随着城市污泥量日益增多,污泥农用受到极大关注。该研究,以水稻扬宁3号为供试材料,设置田间原位试验,研究不施肥(CK)、常规尿素施肥(N240)、施用污泥堆肥(OF)对稻田CH_4和N_2O排放,土壤和植物重金属累积的影响。结果表明,OF处理水稻生长季CH_4排放量为68.09 kg·hm~(-2),是N240和CK处理的两倍多(P<0.05);N_2O排放量为0.94 kg·hm~(-2)(以N计),比N240处理少46%(P<0.05),比CK处理多6倍(P<0.05);OF处理GWP(Global Warming Potential)比N240处理高37%(P<0.05),二者水稻产量相当且无显著差异,OF处理GHGI(Greenhouse Gas Intensity)比N240处理高41%。水稻移栽后3个处理的土壤重金属Cr、Cu、Cd含量均无显著性差异(P>0.05),Ni、Zn含量差异显著:OF处理Ni、Zn含量分别比N240高6%、16%(P<0.05);水稻成熟期土壤中Cr、Cu、Cd含量无显著差异,Ni、Zn含量OF处理分别比N240处理高16%、19%(P<0.05),且均低于《土壤环境质量标准》GB156181995二级标准。重金属在水稻不同部位的富集程度不同,Zn、Cd表现为秆>壳>籽粒,Cr、Ni、Cu表现为壳>秆>籽粒。与N240处理相比,OF处理稻米中重金属Cu含量减少10%(P>0.05),而Cr、Zn、Cd含量分别增加76%、31%、50%(P<0.05)。Ni在N240中未检出,在OF中含量为0.24 mg·kg~(-1)。各处理稻米中重金属含量均在国家食品安全标准限值范围内。综上,污泥堆肥作为稻田施用仍需对其环境效应进行监测。
英文摘要:
With the increasing of municipal sludge, applying sludge in agriculture has been of great concern. Rice YN-3 was used as the test material. The field experiment was conducted to investigate the effects of three different fertilization practices: CK,no N-fertilizer application; N240,applying N-fertilizer at a rate of 240 kg·hm~(-2) (by N); OF, applying composted sludge at a rate of 240 kg·hm~(-2), by N on methane and nitrous oxide emissions from paddy soils and heavy metals accumulation in soil and plant. The results showed that CH_4 emission of treatment OF was 68.09 kg·hm~(-2), being approximately 2-fold those of treatments N240 and CK (P<0.05). The N_2O emission of treatment OF was 0.94 kg·hm~(-2), being 46% lower than that of treatment N240 (P<0.05) and 6-fold that of treatment CK (P<0.05). The GWP (Global Warming Potential), GHGI (Greenhouse Gas Intensity) respectively increased by 37%, 41% of treatment OF compared to treatment N240. After transplant, contents of Cr, Cu, Cd in soil had no significant different among the three treatments, but Ni, Zn had. Ni, Zn in OF treatment was 6%, 16% more than N240 treatment (P<0.05). In the mature, contents of Cr, Cu, Cd in soil had no significant different among the three treatments, Ni, Zn in OF treatment was 16%, 19% more than N240 treatment (P<0.05). The total heavy metals in soil were far below the national standard of environmental quality standards for soils for Grade II (GB 1518-1995). Different heavy metals accumulated in different part of plant. The accumulation of Zn, Cd was straw>crust>seed, and Cr, Ni, Cu was crust>straw>seed. For treatment OF, the content of Cu in rice grain was 10% (P>0.05) less than that of treatment N240, but the contents of Cr, Zn and Cd in rice grain were 76%, 31% and 50% (P<0.05) higher than that of treatment N240, respectively. Ni was not detected in N240 and CK while the content of Ni was 0.24 mg·kg~(-1) in OF. The contents of heavy metals in rice were within the limits of national food safety standard. Combined with the above results, the environmental effects of sludge compost should be monitored.