农药和菌渣对三峡库区油桐生长及土壤化学性质的影响

Effects of Pesticides and Mushroom Residue on Growth and Soil Physical-chemical Properties in Tung Oil Tree of the Three Gorges Reservoir Area

以三峡库区乡土树种油桐(Vernicia fordii)幼苗为材料,在盆栽条件下,研究了百草枯和氰戊·乐果在正常使用剂量(百草枯原药∶水=1∶750,氰戊·乐果原药∶水=1∶1 000)处理下,底施适量菌渣(每盆0.5kg)后油桐幼苗生长状况及土壤理化性质变化。结果表明,未施菌渣的土壤在施用百草枯和氰戊·乐果3个月后,土壤有机质和全N含量比未施药土壤(CK)低,而土壤碱解N、全P、全K、有效P、速效K含量及pH值则高于CK(百草枯处理的土壤全K比对照低除外),油桐幼苗株高和地径生长均受到抑制,但差异不显著;施加菌渣的土壤,再按照同样方法施用两种农药3个月后,与同处理无菌渣土壤相比,土壤有机质、碱解N、全N含量均显著增加(p<0.05),全P、全K、有效P、速效K含量及pH值均显著降低(p<0.05),油桐幼苗生长量(株高和地径)显著提高(p<0.05)。研究提示,即使在正常剂量下使用百草枯与氰戊·乐果也在一定程度上影响了油桐幼苗对土壤养分的吸收及自身生长,降低土壤有机质含量,长期使用将导致土壤板结;而以菌渣作为底肥,有利于油桐幼苗对土壤养分的吸收,促进幼苗生长,且可以防止土壤板结,对在三峡库区进行科学农业生产和减轻面源污染具有指导意义。

A pot experiment was conducted to studying the growth condition of tung oil tree seeding in the Three Gorges Reservoir Area and changes of soil physical and chemical properties under the paraquat （1 ： 750） and fenvalerate-dimerthoate （1 ： 1 000） by mushroom residue. Results show that： 1） In the soil without mushroom residue,after using usual concentration of paraquat and fen- valerate-dimerthoate for 3 months, the contents of organic matter and total N were lower than CIK, but the contents of the nitrogen, total P, effective P, total K, available K and pH were higher than CK（but the content of total K was lower than CK under pa- raquat）, and the growth of height and ground diameter were restricted, but the difference was not significant; 2） After applying mushroom residue in the soil, the contents of organic, nitrogen, total N, seeding height and ground diameter obviously were in- creased but the contents of total P, total K, effective P, available K and pH were decreased （p〈0.05）. This study suggests that pa- racluat and fenvalerate-dimerthoate have an eflect on the soil physical-chemical properties in a normal way. They will go against tung oil tree seeding absorbing nutrients from the soil and growth, which can make soil harden by long-term application of pesticides. Applying mushroom residue in the soilt which can mitigated the impact of pesticides on soil physical and chemical properties, mak- ing the soil nutrients be absorbed and seeding growth. Furthermore, applying mushroom residue in the soil can prevent soil harden- ing. So, this study provides a scientific guidance for agricultural production and reducing non-point source pollution of agriculture in the Three Gorges Reservoir Area.