【作者】 白梅；

【导师】 铁柏清；

【作者基本信息】 湖南农业大学 ， 环境科学， 2011， 硕士

【摘要】 通过室内淋溶柱模拟试验,研究了降雨量、降雨pH值、氮磷肥等因素对土壤中Pb、Zn、Cd、As等重金属淋失的影响；并且通过盆栽模拟试验,分别研究了降雨量和施肥与植被种植情况双重因素对土壤中Pb、Zn、Cd、As等重金属淋淋失的影响。主要研究结果如下：在相同降雨量下,随着降雨pH值的升高,淋溶液中Pb、Zn、Cd、的浓度和总量都逐渐变小,而淋溶液中As的浓度和总量随pH值的升高呈增大趋势。在研究降雨量这一影响因素时,我们发现淋溶液中Pb、Zn、Cd、的浓度在相同pH值下,随着降雨量的增加而逐渐减小；但是淋溶液中Pb、Zn、Cd、的总量随降雨量的变化规律在不同pH值下而有所不同。在pH为3.0和4.5时,淋溶液中Pb、Zn、Cd的总量随着降雨量的增加明显增加；在pH为5.3时,淋溶液中Pb的总量随着降雨量的增加明显增加。在pH值为7.0时,淋溶液中Pb的总量随降雨量的增加变化不明显。在pH值为5.3和7.0时,淋溶液中Zn、Cd的含量在降雨量较小时,随降雨量的增加而增加,在降雨量较大时,变化不明显。在同一pH值下,淋溶液中As的浓度随降雨量的变化规律不明显,但淋溶液中As的含量随降雨量的增加而明显增加。在不施磷肥和少量施磷肥时,土壤中Pb的淋失较大；随着磷肥施用量的增加,Pb的淋失逐渐减小；施肥量达到一定程度后,土壤中Pb的淋失随着磷肥施用量增加变化不明显。土壤中Zn的淋失量,随着磷肥施用量的逐渐增加,呈跳跃式增大的趋势。土壤中Cd、As的淋失量,随着磷肥施用量的增加而增大,但是随着淋溶次数的增多,磷肥施用量对土壤中Cd、As的淋失的影响逐渐减弱。不同氮肥施用量对土壤中Pb的淋失影响不明显。氮肥施用一定时间后,土壤中Zn、Cd的淋失随着施肥量的增加而减小盆栽种植水稻时,从不同降雨量来看,土壤中淋出Pb的总量在20mm降雨量时小于5.7mm降雨量时；而土壤中淋出Zn、Cd、As的总量在20mmm降雨量时大于5.7mm降雨量时。从不同种植密度来看,土壤中淋出Pb、Cd、As的总量在各个降雨量时都随着水稻种植密度的增大而减小；土壤中淋出Zn的总量在5.7mm降雨量时随种植密度的增加变化不大,而在20mm降雨量时,土壤中淋出Zn的总量在正常种植密度时和2倍正常种植密度时都小于不种植时。盆栽种植小白菜时,淋溶液中Pb、Cd的浓度变化没有明显规律,土壤中Pb、Cd的淋失规律有待进一步研究。在20mm降雨量时,土壤中淋出Zn的总量随着种植密度的增加没有变化；而在50mm和80mm降雨量时,土壤中淋出Zn的总量都是在低种植密度时增加,高种植密度时又减小。土壤中淋出As的总量在相同的种植密度下随着降雨量的增加而增大；从不同种植密度来看,在20mm降雨量时,土壤中淋出As的总量在各个种植密度下相差不大；在50mm降雨量和80mmm降雨量时,土壤中淋出As的总量在种植小白菜时少于不种植小白菜时。在盆栽种植小白菜进行施氮肥试验中,尿素对土壤中Pb的淋失影响没有明显规律。不种植时,土壤中Pb、Zn、Cd、As的淋出量随着氮肥施用量的增加略有增大。低种植密度时,土壤中Zn、As的淋出量随着氮肥施用量的增加呈增大趋势,而Cd的淋出量呈减小趋势。高种植密度时,土壤中Zn、Cd、As的淋出量在施肥条件下都远远小于不施肥时。更多还原

【Abstract】 The effect of rainfall, pH, nitrogen, phosphate on the leaching loss of Pb, Zn, Cd, As in the soil had been researched through leaching column simulation experiments and the effect of rainfall&vegetation and phosphorus&vegetation on the leaching loss of Pb, Zn, Cd, As in the soil been researched through the pot experiments. The principal results are as follows:In the same rainfall, the concent and total of the Pb, Zn, Cd in the leaching liquor was decreases gradually with the increased of the rainfall pH value, however, the concent and total of the As in the leaching liquor was increased gradually at the same time.The concent of the Pb, Zn, Cd in the leaching liquor was decreases gradually with the increased of the rainfall at the same rainfall pH value. However the total of the Pb, Zn, Cd in the leaching liquor had different variety rule with the increased of rainfall in different rainfall pH value.The total of the Pb, Zn, Cd in the leaching liquor was increased obvious with the increased of rainfall when the rainfall pH value was 3.0 and 4.5. While the total of the Pb in the leaching liquor was increased obvious with the increased of rainfall when the rainfall pH value was 5.3 and it has no change when the rainfall pH value was 7.0.Meanwhile, when the rainfall pH value was 5.3 and 7.0, the total of the Zn, Cd in the leaching liquor was increased obvious with the increased of rainfall when the rainfall was small and it had no change when the rainfall was large.There had no change about the concent of the As in the leaching liquor as the rainfall, while the total of the As in the leaching liquor was increased obvious with the increased of rainfall.The total of Pb leaching from the soil was more when there was no phosphorus or little Phosphorus, and it was decreases gradually with the increased of phosphorus usage, however it was no more change when the phosphorus usage great to a certain degree. The total of Zn leaching from the soil was salutatory increased with the increased of phosphorus usage. The total of Cd and As leaching from the soil was increased gradually with the increased of phosphorus usage, and the effect of the phosphorus usage was decreases gradually,The effect of the nitrogen usage on the leaching loss of Pb in the soil was not clear. The total of Zn and Cd leaching from the soil was decreases gradually with the increased of the nitrogen usage when some time later.When we plant rice in the pot for research, we found the follows results. When the rainfall was 20mm, the total of Pb leaching from the soil was less than it was 5.7mm,while the total of Zn, Cd and As leaching from the soil was more than it was 5.7mm. The total ofPb, Cd and As leaching from the soil was decreases gradually with the increased of the planting density of the rice. When the rainfall was 5.7mm, the total of Zn leaching from the soil has no obvious change. When the rainfall was 20mm, the total of Zn leaching from the soil was larger at no planting than little planting or densitily planting.When we plant pakchoi in the pot for research, we found the follows results. The concent of the Pb, Cd in the leaching liquor has no rules, and it need more research. When the rainfall was 20mm, the total of Zn leaching from the soil was no obvious change with the increase of the planting density. When the rainfall was 50mm or 80mm, the total of Zn leaching from the soil was increased at little planting and it was decreased at densitily planting.The total of As leaching from the soil was increased with the increased of the rainfall at the same planting density. When the rainfall was 20mm, the total of As leaching from the soil was no obvious change at the different planting density. When the rainfall was 50mm or 80mm, the total of As leaching from the soil was larger at no planting than it was planting.When we plant pakchoi in the pot for nitrogen research, we found the follows results. Urea had no obvious effect on the leaching loss of Pb in the soil. The total of Pb, Zn, Cd and As leaching from the soil was some increased with the increased of the nitrogen usage when it was no planting. With the increased of the nitrogen usage, the total of Zn and As leaching from the soil was obvious increased while the total of Cd was decreased when it was little planting. When it was densitily planting, the total of Zn, Cd and As leaching from the soil was much smaller at use nitrogen than no nitrogen.更多还原