通过盆栽试验研究了单纯紫云英翻压(GM),以及紫云英与石灰共施(GM0HL)、紫云英+常量石灰晚施(GM5HL)、紫云英+减量石灰晚施(GM5LL)等处理对土壤性状、水稻根表铁膜及水稻对镉吸收转运的影响.结果表明,相较于对照(CK),翻压紫云英可显著(P＜0.05)提高土壤有机质含量 2.1～2.7 g·kg-1.相较于GM处理,增施石灰后,土壤pH值显著提高0.38～0.78 个pH单位,且土壤有效态Cd含量显著降低21.71%～41.28%.在紫云英快速腐解末期,增施了石灰的处理(GM0HL、GM5HL、GM5LL),土壤Eh显著高于GM处理.与CK相比,GM0HL、GM5HL、GM5LL 处理在分蘖期的水稻根表铁膜 Fe 含量分别显著下降43.34%、38.82%和29.00%,根表铁膜Cd含量分别显著下降43.72%、35.56%和12.72%.主成分分析的结果显示,土壤pH值和有机质含量是影响水稻Cd吸收的关键因子,提高土壤pH值和有机质含量可以降低土壤Cd有效性,增加水稻根表铁膜厚度和根表铁膜Cd含量,从而抑制水稻对Cd的吸收.在试验条件下,紫云英翻压 5d后减量施用石灰,既可以达到较好的降Cd效果,又能在一定程度上减少Cd污染耕地的治理投入.
Effect of application of lime with Chinese milk vetch on the cadmium uptake in rice
In the present study,a pot experiment was conducted to reveal the effects of application of Chinese milk vetch(GM),as well as the combination of Chinese milk vetch and lime(GM0HL),Chinese milk vetch and lime late application(GM5HL),Chinese milk vetch and reduced lime late application(GM5LL)on soil properties,root iron plaque and the uptake and transport of Cd in rice plants.The results showed that the soil organic matter content was significantly(P＜0.05)increased by 2.1-2.7 g·kg-1 after turning over of Chinese milk vetch than that of control(CK).Compared with the GM treatment,the soil pH was significantly increased by 0.38-0.78 pH units with application of lime,and the soil available Cd content was significantly decreased by 21.71%-41.28%.In the late stage of rapid decomposition of Chinese milk vetch,soil Eh of the treatments with lime(GM0HL,GM5HL,GM5LL)was significantly higher than that of GM.Compared with the CK treatment,the Fe content in root iron plaque of rice at the tillering stage was significantly reduced by 43.34%,38.82%and 29.00%in GM0HL,GM5HL and GM5LL treatments,respectively,and the Cd content in root iron plaque was significantly decreased by 43.72%,35.56%and12.72%,respectively.The principal component analysis results showed that,soil pH and organic matter content were two key factors,which significantly affected the absorption of Cd by rice.Increasing of soil pH and organic matter content could reduce the availability of Cd in soil,increase the thickness of root iron plaque and the content of Cd in root iron plaque,thus inhibit Cd uptake by rice.In the experiment conditions,it could reduce Cd uptake and the cost in remediating Cd contaminated farmland by application of the reduced amount of lime 5 days after the overturning of Chinese milk vetch.
万方数据
维普
