深松对黑土物理特性及真菌群落结构的影响

The Effect of Deep Loosening on the Physical Properties and Fungal Community Structure of Black Soil

为阐明不同深松方式对黑土耕层物理特性与真菌群落结构影响,于2018‒2020年开展大田试验,以旋耕为对照,设3个深松年限(1,2,3 a)和3个深松深度(25,35,45 cm)共10个处理,分析0~20 cm耕层物理特性及玉米根际土壤真菌群落结构变化。结果表明:相较于旋耕,深松可使0~10 cm土层土壤含水量、温度、容重降低,土壤毛管孔隙度增加。从深松深度来看,深松45 cm(CS)处理对0~10 cm土层土壤含水量影响最大,深松25 cm(QS)处理土壤温度整体降幅最大,深松35 cm(SS)处理土壤容重最小;各处理可使10~20 cm土层土壤含水量、容重升高,使毛管孔隙度降低,这一规律与0~10 cm土层相反。同时,深松后土壤结构指数(generalized soil structure index,GSSI)、土壤三相结构距离指数(soil three-phase structure distance,STPSD)与土壤容重分别呈极显著正、负相关。Ace指数与土壤温度呈显著正相关,表明土壤温度提高有利于真菌群落丰富度提升。相较于旋耕处理,深松处理导致子囊菌门(Ascomycota)相对丰度大幅降低,被孢霉门(Mortierellomycota)、担子菌门(Basidiomycota)相对丰度大幅增加。这表明剧烈的土壤扰动在影响耕层水热状况的同时,也改变了真菌群落结构,使其向新群落结构发展。从属水平看,各深松处理较CK(旋耕)提高双极霉属(Bipolaris)、葡萄状穗霉属(Stachybotrys)、附球菌属(Epicoccum)、Dioszegia和Papiliotrema相对丰度,降低Myrmecridi⁃um、帚枝霉属(Sarocladium)、Plectosphaerella(织球壳菌属)、枝鼻菌属(Cladorrhinum)和尾孢菌属(Cercophora)相对丰度。根据单因子相似性分析(analysis of similarities,ANOSIM),各处理间真菌群落差异显著(R=0.253,p=0.002)。深松深度相较于深松年限更易使真菌群落产生差异,而深松年限增加会减小不同深度造成的差异。

To elucidate the effects of different deep loosening methods on the physical properties and fungal community structure of the black soil plow layer.Field experiments were conducted from 2018 to 2020,using rotary tillage as a control.A total of 10 treatments were set up with 3 deep loosening years(1,2,3 a)and 3 deep loosening depths(25,35 and 45 cm).The physical characteristics of the 0‒20 cm plow layer and the changes in fungal community structure in the maize rhizosphere soil were analyzed.Compared to rotary tillage,deep loosening can lead to a decrease in soil moisture content,temperature,and bulk density in the 0‒10 cm soil layer,and an increase in soil capillary porosity.From the perspective of deep loosening depth,the 45 cm(CS)deep loosening treatment has the greatest impact on the soil moisture content of the 0-10 cm soil layer,the 25 cm(QS)deep loosening treatment has the largest overall decrease in soil temperature,and the 35 cm(SS)deep loosening treatment has the smallest soil bulk density;Each treatment can increase the soil moisture content and bulk density of the 10-20 cm soil layer,and reduce the capillary porosity,which is opposite to the 0‒10 cm soil layer.At the same time,(generalized soil structure index,GSSI)and(soil three-phase structure distance index,TPSD)after deep loosening are significantly positively and negatively correlated with soil bulk density.The Ace index is significantly positively correlated with soil temperature,indicating that increasing soil temperature is beneficial for enhancing fungal community richness.Compared to rotary tillage treatment,deep loosening treatment resulted in a significant decrease in the relative abundance of Ascomycota,while Mortierellomycota and Basidiomycota increased significantly.This indicates that severe soil disturbance not only affects the water and heat conditions of the tillage layer,but also changes the fungal community structure,leading it to develop towards a new community structure.At a subordinate level,each deep loosening treatment increased the relative abundance of Bipolaris,Stachybotrys,Epicocum,Dioszegia,and Papiliotrema compared to CK(rotary tillage),while reducing the relative abundance of Myrmecridium,Sarocladium,Plectosphaerella,Cladorrhenum,and Cercophora.According to(analysis of similarities,ANOSIM),there were significant differences in fungal communities among the treatments(R=0.253,p=0.002).The depth of deep loosening is more likely to cause differences in fungal communities compared to the number of years of deep loosening,and increasing the number of years of deep loosening will reduce the differences caused by different depths.