玉米与龙葵间作模式对植物生长及Cd富集特征的影响

Effects of intercropping modes of Zea mays L.and Solanum nigrum L.on plant growth and Cd enrichment characteristics

为探究最优的间作修复模式,通过田间小区试验,以玉米和超富集植物龙葵为研究对象,设置单作玉米(CK1)、单作龙葵(CK2)、宽窄行玉米宽行间作单行龙葵(T1)、宽窄行玉米宽行间作双行交错龙葵(T2)、等行距单行玉米间作单行龙葵(T3)、等行距单行玉米间作双行交错龙葵(T4)、等4行距玉米间作等4行距龙葵(T5)7种种植模式,研究不同模式下玉米和龙葵各器官生物量、土地当量比、Cd含量、富集系数和转运系数、总Cd提取量、根际土壤pH和有效态Cd含量的变化。结果显示,5种间作模式的土地当量比均大于1。与CK1相比,T3间作模式玉米产量增加15.6%,T1、T4、T5间作模式玉米产量降幅小于10%,T2间作模式玉米产量减少16.8%;与CK2相比,5种间作模式龙葵单株总生物量没有显著变化。5种间作模式没有显著改变玉米和龙葵各部位的Cd含量,以及生物富集系数和转运系数,但却显著提高了单位面积总Cd提取量,其中T4间作模式最高。除T5外,其他4种间作模式均显著降低了龙葵和玉米根际土壤pH,提高了龙葵根际土壤Cd有效态含量,却降低了玉米根际土壤Cd有效态含量。这表明玉米与龙葵表现为种间生长促进,T1、T3、T4、T54种间作模式不仅可以保障玉米稳产,而且能显著提高修复效率,实现边生产边修复的目的,其中T4间作模式最优。另外,沈阳地区龙葵种子在湖南表现出不适应性,建议选用当地龙葵进行间作修复。

In order to explore the appropriate intercropping restoration mode,a field plot experiment was conducted to investigate the changes in the biomass land equivalent ratio,Cd content,total Cd extraction,bioaccumulation coefficient(BCF),transfer coefficient(TF),pH,and available Cd content in the rhizosphere soil of Zea mays L.and the hyperaccumulator Solanum nigrum L.in seven planting modes,including a monoculture of Z.mays(CK1),monoculture of S.nigrum(CK2),wide-narrow row of Z.mays and single row of S.nigrum intercropped between wide rows(T1),wide-narrow row of Z.mays and double row of interlaced S.nigrum intercropped between wide rows(T2),intercropped equidistant single row of Z.mays and single row of S.nigrum(T3),intercropped equidistant single row of Z.mays and double row of interlaced S.nigrum(T4),and Z.mays and S.nigrum intercropped with four equal rows(T5).The results showed that the land equivalent ratio of the five intercropping modes was greater than 1.Compared with that of CK1,the T3 intercropping mode increased the yield of Z.mays by 15.6%,the T1,T4,and T5 intercropping modes decreased the yield of Z.mays by less than 10%,and the T2 intercropping mode decreased the yield of Z.mays by 16.8%.Compared with that of CK2,the five intercropping modes did not change the total biomass per plant of S.nigrum.The five intercropping modes did not significantly change the Cd content,BCF,and TF of Z.mays and S.nigrum,but significantly increased the total Cd extraction per unit area,and that under the T4 intercropping mode was the highest.In addition to the T5 treatment,the other four intercropping modes significantly reduced the pH of the rhizosphere soil of S.nigrum and Z.mays,increased the Cd content of the rhizosphere soil of S.nigrum,and decreased the Cd content of the rhizosphere soil of Z.mays.This indicated that the intercropping modes improved the growth of Z.mays and S.nigrum.The intercropping modes of T1,T3,T4,and T5 not only ensured the stable yield of Z.mays,but also significantly improved the efficiency of restoration and reached the purpose of repairing while producing,and the T4 intercropping mode was the most effective.In addition,the S.nigrum in the Shenyang area was not adaptable in Hunan Province,so it was suggested to choose local S.nigrum for intercropping restoration.