污泥生物炭添加对铁尾矿土植物生长特性的影响

Effect of sludge biochars on plant growth characteristics of iron tailings soil

以河北省迁安市铁尾矿为基质,通过黑麦草的盆栽试验,研究污泥生物炭为改良剂在短期内对黑麦草生长情况的影响,旨在为城市污泥资源化利用及铁尾矿土壤植物修复提供依据。以城市污泥为主要原料,农业废弃物秸秆为添加剂,在不同温度(300℃、700℃)及秸秆添加量(0%、15%、30%)条件下,进行热解制备生物炭,并以此生物炭为改良剂,与铁尾矿砂混合,以黑麦草为代表植物进行60 d盆栽试验,观察生物炭的添加对铁尾矿土壤的植物生长情况。研究结果表明:300℃热解温度下,添加15%秸秆制备的污泥生物炭(85SC300)和700℃热解温度下,添加30%秸秆制备的污泥生物炭(70SC700)对植物生长的促进效果最好,发芽率分别为86%、94%,高于对照组的49%;株高由对照组的10.52 cm增长至25.32 cm、24.84 cm;叶宽由对照组的4.5 mm增长至8.2 mm、7.2 mm;生物量由对照组的5.21 g增长至10.49 g、9.84 g。选用以上两种污泥生物炭进行不同添加量对黑麦草生长情况影响的试验研究,结果表明,随着污泥生物炭添加量的升高,植物生长情况逐渐改善,在添加量为10%时,综合效果达到最佳,发芽率分别为87%、90%,株高分别为27.21 cm、26.91 cm,叶宽分别为9.0 mm、8.7 mm,生物量分别为10.85 g、11.21 g,进一步增加污泥生物炭的添加量,植物生长情况反而受到抑制。综上所述,城市污泥可以热解制备污泥生物炭,将其与铁尾矿混合后,有助于提高铁尾矿土壤的植物生长,为铁尾矿植物修复提供依据。

Using iron tailings from Qian’an City,Hebei Province as the substrate,the effect of sludge biochars as amendment on the growth of ryegrass in the short term is studied,aiming to provide a basis for urban sludge resource utilization and soil phytoremediation of iron tailings.Using urban sludge as the main raw material and agricultural waste straw as an additive,biochar is prepared by pyrolysis at different temperatures(300℃,700℃)and straw addition amounts(0%,15%,30%).And using biochar as an amendment,mixes with iron tailings sand,and represented by ryegrass,a 60 days pot experiment is conducted to observe the effect of biochar addition on plant growth in iron tailings soil.The results show that at a pyrolysis temperature of 300℃,sludge biochar(85SC300)prepared by adding 15% straw and sludge biochar(70SC700)prepared by adding 30% straw at a pyrolysis temperature of 700℃ have the best promoting effect on plant growth.The germination rates are 86%,94%,respectively,which are higher than the 49% in the control group;the plant height increase from 10.52 cm for control group to 25.32 cm and 24.84 cm;the leaf width increase from 4.5 mm to 8.2 mm and 7.2 mm;the biomass increase from 5.21 g to 10.49 g and 9.84 g.The experimental study on the effect of different addition amounts of sludge biochars on the growth of ryegrass is conducted using the above two types of sludge biochar.The results show that with the increase of the amount of sludge biochar,the growth of plant gradually improved until the addition amount is 10%,the germination rates reach 87% and 90%,the plant heights are 27.21 cm and 26.91 cm,the leaf width are 9.0 mm,8.7 mm,the biomass are 10.85 g,11.21 g,respectively.Further increase the amount of sludge biochar,the growth of plant is suppressed.In summary,urban sludge can be pyrolyzed to prepare sludge biochar,which can be mixed with iron tailings to improve the growth of plant in iron tailings soil and provide a basis for iron tailings plant remediation.