不同钝化剂对微碱性土壤镉、镍形态及小麦吸收的影响

通过大田试验,研究生物炭、褐煤、鸡粪对土壤Cd、Ni形态变化及小麦植株对Cd、Ni富集吸收的影响.结果表明,生物炭可提高土壤pH,褐煤降低土壤pH,均未达显著水平,鸡粪可显著降低孕穗期、成熟期土壤pH,分别降低0. 23和0. 20个单位.生物炭、鸡粪和褐煤单一施用对可交换态Ni含量降低不显著,而对可交换态Cd降低效果显著,小麦不同生长期均以褐煤2%处理降幅最大,分别为30. 50%、43. 34%和31. 20%.小麦地上部、地下部重金属Cd、Ni的含量均有所下降,且降幅随钝化剂添加量的增加而增加,不同生长期均以褐煤2%处理小麦根部Cd含量降幅最大,分别达38. 35%、58. 00%和50. 20%.孕穗期、成熟期均以褐煤2%处理小麦根部Ni含量降幅最大,分别达41. 33%和51. 35%. 3种钝化剂均可降低微碱性土壤中Cd和Ni的有效性,且对镉的钝化效果优于镍;均可有效降低不同时期小麦植株不同器官中Cd和Ni的含量.对于重金属镉,3种钝化剂同等剂量水平下,小麦器官中镉的降低效果依次为褐煤生物炭鸡粪.

Effects of Different Amendments on Fractions and Uptake by Winter Wheat in Slightly Alkaline Soil Contaminated by Cadmium and Nickel

The effects of a single application of three amendments (biochar, lignite, and chicken manure) on the fraction transformations of soil Cd and Ni and uptake by winter wheat are reported to provide reference for passivation and the remediation of heavy metals in soil. Field experiments were conducted to investigate the effects of different passivators on the forms of Cd and Ni in soils at different growth stages of winter wheat, and to analyze the contents of Cd and Ni in different organs of wheat. The results showed that biochar increased soil pH and that lignite reduced soil pH, but not significantly. Chicken manure significantly reduced soil pH at booting and mature stages, and decreased by 0.23 and 0.20 pH units, respectively. The single application of biochar, chicken manure, or lignite did not reduce the exchangeable Ni content significantly, whereas the effect on the exchangeable Cd was significant. Lignite 2% treatment had the greatest decrease in exchangeable Cd at different growth stages of wheat, which were 30.50%, 43.34%, and 31.20%, respectively. The contents of Cd and Ni in the shoots and underground parts of wheat decreased to some extent, and the extent of these decreases increased with the increase of passivator dosage. The decrease of Cd content in wheat roots was the largest under the treatment of lignite 2% at different growth stages, reaching 38.35%, 58.00%, and 50.20% respectively. The greatest decline of Ni content in wheat roots occurred in the lignite 2% treatment at the booting (41.33% decline) and mature stages (51.35%). All the three amendments reduced the availability of Cd and Ni in slightly alkaline soil, and the passivation effect on Cd was better than that of Ni. All three amendments also effectively reduced the content of Cd and Ni in different organs of wheat plants in different growth period. The order of decreasing effect of Cd in wheat organs was lignite > biochar > chicken manure at the same dose of these three passivators.