生物质炭对棉花生长发育及地上部各器中镉富集的影响

为探讨生物质炭对棉花生长发育及地上部各器官中重金属Cd的富集程度,研究不同重金属Cd污染程度(0、1、2、4 mg·kg~(-1))施加生物质炭(0、1.5%和3%)对棉花株高、干物质量、产量、Cd富集量和分配系数的影响及差异性。结果表明:生物质炭对棉花干物质积累量、株高、单铃质量、蕾铃数和棉花产量均有促进作用,能够显著提高棉花的单铃质量、蕾铃数和棉花产量,最高分别为5.8g、6.5个和单株35.75 g,添加生物质炭1.5%和3%两处理间对棉花干物质积累量、单铃质量、蕾铃数和棉花产量差异显著,但对株高差异不显著。随着外源Cd的增加,棉花地上部对Cd的吸收显著增加,重金属Cd在棉花地上部叶片的Cd质量分数明显高于茎秆和蕾铃,最高值分别为0.799 2、0.083 9和0.066 0mg·kg~(-1)。未添加生物质炭水平下, 1、2mg·kg~(-1)低质量分数的Cd对棉花的生长发育有促进作用,当质量分数达到4 mg·kg~(-1)时会对棉花的生长发育产生抑制作用,而添加生物质炭后会减缓这种抑制作用。施入生物质炭对棉花地上部各器官Cd的富集明显降低,其中降低率最大为57.83%,在时间尺度上表现出生育前期降幅较快,后期趋于稳定。生物质炭的施入对棉花地上部各器官Cd的分配系数影响不显著。施入生物质炭3%较1.5%对棉花生长发育和产量的促进作用更明显,而生物质炭的施入对棉花地上部各器官Cd的积累和分配并没有直接影响,研究为新疆棉田Cd污染改良提供参考依据。

Effects of Biochar on Cotton Growth,Development and Cd Enrichment in Above-groud Organs

In order to explore the effect of biochar on cotton growth,development and the enrichment of heavy metal Cd in above-ground organs, the effects and differences of various biochar additions (0,1.5% and 3%, representing C0,C1 and C2,respectively ) on cotton height, dry matter quality, yield, mass fraction of Cd and partition coefficient were studied under four heavy metal conditions (0,1,2 and 4 mg·kg^-1, representing H0,H1,H2 and H3). The results showed that biochar promoted the accumulation content of cotton dry matter, plant height, boll mass, number of bolls and yield, among them boll mass, number of bolls and yield significantly increased to 5.8 g, 6.5 and 35.75 g per plant, respectively. The difference between C1 and C2 treatment was significant on accumulation of cotton dry matter, boll mass, number of bolls and yield, which had evident effect on plant height. With the increase of exogenous Cd in soil, the capacity of absorbing Cd in the cotton aerial parts decreased, among which was more in leaves than stems, bolls, with the maximum values of 0.799 2,0.083 9 and 0.066 0 mg·kg^-1 respectively. The condition of growth and development was promoted under low mass fraction of Cd in soil(1 mg·kg^-1 and 2 mg·kg^-1) and no addition of biochar, but it was inhibited when the mass fraction reached 4 mg·kg^-1 and this inhibition slowed down after biochar addition. The enrichment of Cd in the aerial parts of cotton was significantly reduced 57.83% by the application of biochar. On the time scale, the trend of this reduction was rapid in the early growth period and was stabilized at the later stage. The application of biochar had no significant effect on the partition coefficient of Cd in the aerial part of cotton. The 3% of biochar application evidently promoted the growth and yield of cotton more than 1.5%,while the application of biochar did not directly affect the accumulation and distribution of Cd in the aerial part of cotton. This study provides a reference for Cd pollution improvement in cotton fields in Xinjiang.