生物质炭对水稻微量元素吸收积累的影响

Effects of biochar on uptake and accumulation of trace elements in rice

近年来,生物质炭作为一种土壤改良剂被广泛应用于土壤固碳减排、肥力提升及重金属污染治理。尽管生物质炭能有效降低Cd等重金属在土壤-水稻系统中的生物有效性,然而,生物质炭的施用对水稻吸收微量元素的影响相关研究却相对较少。通过田间试验研究了施用小麦秸秆生物质炭(20 t·hm^(-2)和40 t·hm^(-2))对水稻不同部位微量元素Fe、Mn、Cu、Zn含量的影响,以期为更好地了解生物质炭对水稻吸收积累微量元素的影响提供案例支撑。研究表明,水稻各部位Fe、Cu、Zn含量均为根>秸秆>籽粒,其中,水稻根中Fe含量远高于其他部位,而秸秆中Mn含量远高于根,籽粒部位最低。相较于20 t·hm^(-2)用量,40 t·hm^(-2)生物质炭处理能更好地降低水稻籽粒、秸秆和根中Fe的含量,降幅分别为56.7%、13.0%和39.4%;施用40 t·hm^(-2)生物质炭处理使水稻籽粒和秸秆中Mn含量分别降低了35.6%和43.7%。此外,仅40 t·hm^(-2)生物质炭处理显著降低了水稻根中Cu的含量,降幅为47.2%,仅20 t·hm^(-2)生物质炭处理显著降低了水稻秸秆中Zn的含量,降幅为17.6%。上述结果表明,施用生物质炭处理对水稻体内微量元素Fe、Mn、Cu、Zn含量的影响差异较大,施用生物质炭更有利于降低水稻各部位Fe和Mn的含量,对Cu、Zn含量的影响相对较小,且与生物质炭的施用量有关,应关注高用量的生物质炭对水稻微量元素吸收的影响。

In recent years,biochar as a soil amendment has been widely used in soil carbon sequestration and emission mitigation,fertility improvement,and heavy metal pollution control.Although biochar can effectively reduce the bioavailability of heavy metals such as Cd in the soil-rice system,there is relatively little research on the impact of biochar application on the uptake of trace elements by rice.The effect of applying wheat straw biochar(20 t·hm^(-2) and 40 t·hm^(-2))on the content of trace elements Fe,Mn,Cu,and Zn in different parts of rice was studied through field experiments,in order to provide case support for better understanding of the impact of biochar on the uptake and accumulation of trace elements in rice.Results showed that the Fe,Cu,and Zn contents in various parts of rice are as following order:root>straw>grain.Fe content in rice roots is much higher than that in other parts,while the Mn content in straw is much higher than that in roots,and the grain part is the lowest.Compared with the dosage of 20 t·hm^(-2),40 t·hm^(-2) biochar treatment can better reduce the Fe content in rice grains,straw,and roots,with a decrease of 56.7%,13.0%,and 39.4%,respectively;The application of 40 t·hm^(-2) biochar treatment reduced the Mn content in rice grains and straw by 35.6%and 43.7%,respectively.In addition,only 40 t·hm^(-2) biochar treatment significantly reduced the Cu content in rice roots by 47.2%,while only 20 t·hm^(-2) biochar treatment significantly reduced the Zn content in rice straw by 17.6%.The above results indicate that the application of biochar has a various effects on the trace element Fe,Mn,Cu,and Zn content in rice.The application of biochar is more conducive to reducing the content of Fe and Mn in various parts of rice,and the impact on Cu and Zn content is relatively small,which is related to the application amount of biochar.Attention should be paid to the impact of high dosage of biochar on the absorption of trace elements in rice.