施用给水厂残泥对南北方不同类型农田土壤质量的影响

为评估WTR(给水厂残泥)在农业区污染控制领域的土地应用风险,从土壤理化性质、土壤养分含量、有机质活性、微生物生长和土壤酶活性等五方面,考察了不同WTR添加量(w为0%、2%、5%、10%)对3个南北方农田(土壤)(常州水稻田、寿光和天津蔬菜种植区土壤,依次记做常州土壤、寿光土壤和天津土壤)质量的影响.结果表明:①WTR添加后,各土壤中CEC(阳离子交换容量)提高了23.7%～63.9%；添加WTR有利于调节酸性和碱性土壤pH,使之更适合作物生长,随着WTR添加量由0%增至10%,常州土壤pH由5.45升至6.69,寿光和天津土壤pH则分别由7.57、7.88降至7.26、7.64.②添加适量WTR不会造成土壤中P、K、Fe、Al、Ca、Mg、Cu、Mn和Zn等多种有效态元素含量的缺失,特别是在富P(>50 mg/g)土壤中施加2%～10%的WTR,既能满足植物生长对有效P的需求,又能降低P的淋溶风险.③在施肥和不施肥条件下,WTR添加量≤5%时均能增加土壤w(活性有机质),促进土壤微生物生长,提高土壤脱氢酶和总磷酸酶活性.由于WTR对有机P底物的强吸附作用,不施肥条件下,WTR添加量达到10%时,土壤总磷酸酶活性降低了55%；而施加有机肥会削弱或抵消这种不利影响,土壤总磷酸酶活性可提高至未添加WTR时的1.7倍.因此,添加适量WTR能有效改善我国南北方不同类型农田土壤质量. 

Effects of Drinking Water Treatment Residuals on the Quality of Different Soils from Southern and Northern Agricultural Regions

In order to promote the application of drinking water treatment residuals(WTR) for soil pollution control, the effects of WTR amendment on the quality of different soil types from southern and northern agricultural regions were investigated, including paddy soil from Changzhou City denoted by Changzhou soil, as well as soils from the vegetable cultivation areas of Shouguang and Tianjin cities denoted by Shouguang and Tianjin soils, respectively. The results showed that following WTR amendment(2%, 5%, 10%), cation exchange capacities of agricultural soils were enhanced by 23.7%-63.9%, and soil pH was more suitable for crop growth. As the WTR amendment rate increased from 0% to 10%, the pH value of Changzhou soil increased from 5.45 to 6.69, and the pH value of Shouguang and Tianjin soil decreased from 7.57 to 7.26 and 7.88 to 7.26, respectively. WTR amendment exerted non-adverse effect on the contents of available elements in soils(e.g., P, Fe, Al, K, Ca, Mg, Mn, Cu and Zn)； in particular, amending WTR in P-rich(>50 mg/g) soils could still satisfy the available-P requirement for crop growth, and meanwhile reduce P leaching risk. Under both fertilization and non-fertilization conditions, WTR amendment enhanced the active organic matter in soils, the soil bacterial abundance and stimulated the soil enzyme activity. WTR amendment rate should be controlled under 10%； otherwise the total soil phosphatase activity would be decreased due to the strong sorption of WTR to organophosphorus substrates. As the WTR amendment rate got up to 10%, the total soil phosphatase activity was decreased by 55%, but applying organic fertilizer could weaken or even counteract such adverse effects. Overall, applying WTR with appropriate amendment rate could effectively improve the quality of soils from the southern and northern agricultural regions.