接种AMF与间作对红壤上玉米和大豆种间氮素竞争的影响

Effects of AMF inoculation on maize and soybean interspecific competition of N uptake on red soil under intercropping condition

盆栽条件下对间作、尼龙网分隔和单作的玉米和大豆接种丛枝菌根真菌(arbuscular mycorrhizal fungus,AMF)Funneliformis mosseae(FM)和Funneliformis etunicatum(FE),以试验AMF和种植方式对玉米和大豆作物种间氮素竞争的影响。结果表明,接种FM和FE的玉米和大豆植株无论何种种植方式均有一定比例的侵染,侵染率为37%–56%。不管AMF接种与否,玉米的生物量大小依次为间作>尼龙网分隔>单作,大豆生物量大小依次为单作>尼龙网分隔>间作,说明间作促进了玉米的生长,却抑制了大豆的生长。无论何种种植方式,AMF处理均不同程度提高了玉米和大豆植株的氮含量和吸收量,降低了玉米和大豆根际土壤碱解氮的含量。在同一AMF处理3种种植方式内,间作种植对玉米植株氮含量和吸收量的促进作用最为明显,而单作对大豆植株氮含量和吸收量的促进作用最为明显。所有处理中,玉米对营养的竞争力和对氮的竞争比率均优于大豆,无论何种AMF处理,间作处理下的玉米相对于大豆的营养竞争能力均优于尼龙网分隔处理,无论何种种植方式,AMF处理下的玉米相对大豆对氮的竞争比率高于NM处理,可见,玉米始终处于竞争优势地位,而大豆则始终处于劣势。接种AMF均显著地促进了玉米和大豆的生长,并显著提高了玉米相对于大豆的竞争能力,在FM接种及间作模式下,玉米和大豆对土壤碱解氮的吸收利用较多,但玉米相对大豆对营养的竞争力和氮竞争比率最高,表明AMF影响了寄主植物的种间竞争力,并且在AMF和间作协同作用下的影响最为明显。

Three mycorrhizal treatments [uninoculation（NM）, Funneliformis mosseae（FM） inoculation, Funneliformis etunicatum（FE） inoculation] and three cropping ways（intercropping, nylon net separation and monocropping） were set up for exploring the effects of arbuscular mycorrhizal fungi（AMF） and different cropping ways on plant interspecific competition of N uptake on red soil. Results showed that the roots of maize and soybean both were infected by FM and FE fungi, and the colonization percentage ranged from 37% to 56%. The plant height, root length and biomass of maize were obviously higher than those of soybean. Under treatment of AMF inoculation or uninoculation, the biomass of maize increased in the order of intercroppingnylon net separationmonocropping, and that of soybean monocroppingnylon net separationintercropping, showing that intercropping promoted maize growth, but inhibited soybean growth. No matter what kinds of cropping ways, AMF inoculation improved nitrogen（N） uptake of maize and soybean in different degrees, decreased the available N content in soil planted with maize and soybean. Under treatment of AMF inoculation or uninoculation, intercropping promoted obviously the N uptake of maize, and also promoted the N uptake of monocropping soybean. In all the treatments, the competitive strength and N competitive ratio of maize were better than those of soybean. In any case of AMF treatment, the relative competitive strength of maize against soybean under intercropping condition was better than that under nylon net separation condition. Using any way of cropping, the N competitive ratio of maize to soybean under AMF inoculation treatment is better than that under uninoculation treatment. In conclusion, maize was always in competitive advantage position, while soybean was always in disadvantage. Inoculation of FM and FE significantly promoted the growth of maize and soybean, and significantly improved the relative competition of maize against soybean. Under FM inoculation and intercropping treatment the absorption of available N of maize and soybean was higher, and the relative competitive strength and N competitive ratio of maize to soybean were the highest. These revealed that AMF could affect the competitiveness between the host plant species, and this influence was most obvious under the complex condition of AMF and intercropping planting.