玉米秸秆在土壤中腐解的动态变化及其对Cu(Ⅱ)、Cd(Ⅱ)吸附-解吸的影响

通过室内培养和吸附-解吸试验,研究玉米秸秆腐解后石灰性褐土对Cu2+、Cd2+吸附-解吸的影响。结果表明,玉米秸秆腐解量随培养时间的延长而增加,到第7周时,腐解总量可达45%,添加常规量秸秆处理(S1)与加倍量处理(S2)的腐解量差别不明显;常规量秸秆处理(S1)的腐解速率大于加倍量处理(S2),但均随培养时间的延长而减少。土壤对Cu2+的吸附量随秸秆培养时间的延长表现为先升高后降低,吸附量在第21天时达到最大值;Cu2+浓度为1 000mg/L时土壤对Cu2+吸附量显著高于Cu2+浓度为600mg/L处理;而Cu2+的解吸量在秸秆腐解前期变化不明显,到培养第21天后迅速降低。在相同的Cu2+浓度下,Cu2+的吸附量和解吸量受Cd2+浓度影响均不明显。Cd2+浓度为1mg/L时,土壤对Cd2+的吸附量随秸秆培养时间的延长变化不明显,但随Cu2+浓度的增加而减小;而Cd2+浓度为10mg/L时,在Cu0处理和Cu1000处理时,不同培养时间土壤对Cd2+吸附量影响不明显,但Cu600处理下,在培养的第21天后,土壤对Cd2+的吸附量显著增加。土壤Cd2+的解吸量均随秸秆培养时间的延长表现为先升高后降低,在第21天时达最小值,而Cd2+的解吸量随共存Cu2+浓度的增加而先增加后降低。

Maize Straw Decompose Dynamic Change and Effects on Cu(Ⅱ) and Cd(Ⅱ) Adsorption-Desorption in Calcareous Cinnamon Soil

The paper studied on the effects of maize straw decompose on Cu and Cd adsorption-desorption in calcareous cinnamon soil by incubated method and adsorption-desorption experimentation.Results showed that maize straw decompose quantity increased with incubated time extended,and the decompose quantity was reached 45% when the incubated time to 7th week.There was no significant different between routine straw added quantity treatments(S1) and double added quantity treatment(S2).And the decompose speed of S1 was faster than that of S2,but the decomposed speed decreased with incubated time extended.Cu2+ adsorption amount increased at first and then decreased and last to a steady value with incubated time extended,and it reached a maximum value on 21st day,the Cu2+ adsorption amount that Cu2+ concentration was 1 000 mg/L treatment was significant higher than that of Cu2+ concentration was 600 mg/L treatment.But there was no significantly changed of Cu2+ desorption amount during the incubated prophase,and it was rapidly decreased after incubated 21st day.The effect of Cd2+ concentration on Cu2+ adsorption amount and desorption amount was no significant different.Cd2+ adsorption amount was no significantly change with incubated time extend when the Cd2+ concentration was 1 mg/L,but it was decreased with Cu2+ concentration increased.And when Cd2+ concentration was 10 mg/L,there was no significantly affect of incubated time on Cd2+ adsorption amount under Cu0 and Cu1000 treatments,but under Cu600 treatment,Cd2+ adsorption amount increased significantly after incubated 21st day.Cd2+ desorption amount increased at first and then decreased with incubated time extend,and Cd2+ desorption amount reached minimum value on 21st day,and it increased at first and then decreased with concomitant Cu2+ concentration increased.