生物炭对棕壤大豆根际微生物的影响

Effect of Biochar on Soybean Rhizosphere Microbes From Brown Earth Soil

为了探讨生物炭对棕壤大豆根际微生物群体的影响,试验设置CK(0kg.hm-2),C1(750kg.hm-2),C2(1500kg.hm-2),C3(3000kg.hm-2),C4(6000kg.hm-2)5个生物炭梯度,分别在大豆苗期、开花期、结荚期、鼓粒期和成熟期测定土壤微生物数量、pH值和田间持水量的动态变化,并观察微生物在炭粒与土粒中的分布情况。结果表明:多数生育期生物炭处理提高大豆根际土壤中细菌数量,最高增加94.9%;前4个生育期,与CK相比真菌和放线菌数量减少,分别减少13.6倍和47.2%,但成熟期C4真菌增加0.51倍,而放线菌则提高2.09%。细菌真菌比例提高,成熟期C4比CK高70.7%。土壤pH提高,成熟期C4比CK高5.6%。炭粒中微生物数量少于土粒。通过增加土壤细菌与真菌数量比例,以及提高pH,生物炭可能成为缓解大豆连作障碍的土壤改良剂。

To investigate the impact of biochar on soybean rhizosphere population,five biochar application rates were applied in soybean field and samples were collected on seedling stage,blooming stage,bearing pod stage,seed filling stage and mature stage.Dynamic variation of bacteria,fungi and actinomycetes population,soil pH and water holding capacity were studied.Meanwhile,allocation of microbes in biochar particle and soil particle was observed.Results indicated that in most stages,biochar improved rhizosphere bacteria population with 94.9% mostly.Fungi and actinomycetes number decreased in former four stages,with 13.6 fold and 47.2% respectively.However,to mature stage,fungi number increased 0.51 fold and actinomycetes increased 2.09%.Bacteria and fungi ratio increased mostly 70.7% on mature stage.pH went up with 5.6% for C4 relative to CK on mature stage.Compared with soil particles,more microbes in biochar particles were not observed.Through improving bacteria and fungi ratio and pH,biochar is expected to act as soil amendment on alleviating obstacles led by soybean continuous cropping.