施用富铜锌猪粪对低丘茶园土壤及茶叶重金属积累的影响

Effects of Copper and Zinc-rich Pig Manure Application on Accumulation of Heavy Metals in Soil and Tea Plant of Hilly Tea Garden

为了解施用富铜锌畜禽粪对低丘茶园红壤及茶叶重金属积累的影响,设计施用化肥、化肥+猪粪、单施猪粪和2倍于单施猪粪的猪粪用量4个施肥处理,进行为期4年的观察研究。结果表明,施用猪粪可预防土壤酸化,有利于红壤肥力的提高。适量施用猪粪可提高土壤Cu和Zn含量,改善茶树Cu和Zn营养状况。无论是施用化肥、化肥+猪粪,还是单施猪粪(或2倍猪粪用量),连续施用4年对土壤Pb、Co、Ni、Hg和As含量均无明显的影响,不会引起这些元素的明显积累。但过量或长期施用富含Cu和Zn猪粪,可引起土壤Cu、Zn和Cd显著积累,积累量可超过它们的土壤环境质量标准值。施用化肥、化肥+猪粪、单施猪粪和2倍于单施猪粪的猪粪用量4个施肥处理的土壤Cu的年积累速率分别为0.39,2.05,4.29,9.22mg/(kg·a),土壤Zn的年积累速率分别为0.43,4.78,10.55,22.44mg/(kg·a)。土壤中积累的Cu主要向有机质结合态和交换态转化,Zn主要向交换态、有机质结合态和氧化铁结合态转化。建议在茶园施用富含Cu和Zn畜禽粪时应注意控制施用量,不宜长期连续施用。

In order to understand the effects of copper and zinc-rich pig manure application on accumulation of heavy metals in red soil and tea plant of hilly tea garden,a field experiment was conducted for four years.The experiment included four treatments,i.e.,chemical fertilizers,1/2pig manure and 1/2chemical fertilizers,pig manure,and double pig manure.The results showed that application of pig manure could prevent soil acidification,and improve fertility of red soil.The appropriate amount of pig manure could improve soil Cu and Zn status,and levels of Cu and Zn in tea.Four-year continuous fertilization for each of four treatments had no significant effects on concentrations of Pb,Co,Ni,Hg,and As in the soils,no significant accumulation of these metals in the soils were found.However,excessive or long-term application of copper and zinc-rich pig manure could cause Cu,Zn and Cd accumulation in the soils,the accumulation of Cu,Zn and Cd in a relatively short period could exceed their soil environmental quality standards.Annual accumulation rates of soil Cu and Zn were 0.39,0.43mg/（kg·a）for application of chemical fertilizers,2.05,4.78mg/（kg·a）for application of 1/2pig manure and 1/2chemical fertilizers,4.29,10.55mg/（kg·a）for application of pig manure,and 9.22,22.44mg/（kg·a）for application of double pig manure,respectively.The Cu accumulated in the soils was mainly transformed to the organic bound and exchangeable forms,and that of Zn was mainly transformed to the organic bound,exchangeable,and oxide-bound forms.It suggested that the application amount of Cu-and Zn-rich poultry manure in tea garden should be controlled,and continuous application of pig manure in tea garden should be avoided.