【摘要】 为生物炭应用于农田Cd污染的控制及治理提供相关科学依据,研究通过根箱试验,研究棉纤维生物炭对水稻根际和非根际土壤可交换态和不可交换态Cd含量及水稻植株中Cd分配的影响。研究表明:随着棉纤维生物炭的施用量增加,根际和非根际土壤可交换态Cd含量都呈下降趋势,同时不可交换态Cd含量都呈上升趋势。随着棉纤维生物炭的施用量增加,非根际土壤pH值呈逐渐上升趋势。非根际土壤pH值与可交换态Cd含量之间存在显著负相关关系,与不可交换态Cd含量之间存在显著正相关关系。可见,施用棉纤维生物炭可在一定程度上提高非根际土壤pH值,进一步降低了非根际土壤可交换态Cd含量;而根际土壤可交换态Cd含量的下降,主要受棉纤维生物炭的理化性质影响,受土壤pH值影响不大。随着棉纤维生物炭的施用量的增加,水稻各部位Cd含量及累积量都呈现下降趋势,其中籽粒Cd含量的下降幅度最大,为36.57%,根的Cd含量的下降幅度最小,为12.56%。由于茎鞘的生物量和Cd含量都较大,茎鞘中Cd累积量最高,平均为25.44μg plant^-1,是籽粒的2.85倍。因此,在进行农田土壤Cd修复的同时,除了要关注农产品Cd污染,还要考虑如何妥善处理大量的富集Cd的农业废弃物,避免产生二次污染风险。更多还原

【Abstract】 A root box experiment was conducted to study the effects of cotton fiber biochar on the contents of exchangeable and non-exchangeable Cd in rhizosphere and non-rhizosphere soil and its distribution in rice plants.The results showed that the exchangeable Cd content declined, the non-exchangeable Cd content increased in rhizosphere and non-rhizosphere soil, and the non-rhizosphere soil p H increased with the increase in the application amount of cotton fiber biochar. There was a significant negative correlation between soil pH and exchangeable Cd content, and a significant positive correlation between soil pH and non-exchangeable Cd content in non-rhizosphere soil. Therefore, the application of cotton fiber biochar increased the non-rhizosphere soil pH and reduced further the exchangeable Cd content in non-rhizosphere soil. The decrease of the exchangeable Cd content in rhizosphere soil was because of the physicochemical property of cotton fiber biochar. With the increasing of the application amount of cotton fiber biochar, the content and accumulation of Cd in all parts of rice showed a declining trend, and the contents of Cd in grain and root decreased by 36.57% and 12.56%, respectively. Because of the large biomass and Cd content of the stem sheath, the accumulation of Cd in the stem sheath was the highest of about 25.44 μg plant-1, 2.85 times higher than that in the grains. Therefore, in addition to focusing on the Cd pollution of agricultural products, we should consider the proper disposal of a large amount of agricultural waste enriched with Cd in order to avoid the risk of secondary pollution.更多还原