Effects Of The Soil Dominant On The Germinating And The Seeding Growth Of The Soybean

Candidate: Tang YuanZhengMajor:Crop Culture and Farming SystemSupervisor: Zu WeiThis experiment was carried out in the experimental plot in Northeast Agricultural University, the soil type is black soil, four treatments of rotation system were set up, the first treatment is corn-wheat-soybean, the second treatment is wheat-soybean-soybean, the third treatment is soybean- wheat-soybean, the fourth treatment is soybean-soybean- soybean, and the previous four years was also planted with soybean. the dominant fungus have been separated from the different soil after each growing season. the four varieties of soybean which were used are: NEAU No.42, Baofeng No 7, Suinong No 10 and Hefeng No 35.The results are as follows:1.The dominant fungus of the soil are Trichoderma, Penicillium in any kinds of rotation system and one-crop system, the dominant fungus of the soil are Penicillium, Mucor, Rhizopus in the growing season of profuse flowering season and podding season. In contrast, the species and the quantities of the dominant fungus of the soil are comparatively more. The quantities of the dominant fungus of the soil in the profuse flowering and podding periods are more.2.The dominant fungus of the soil in all treatments almost all cause the decreasing tendency of fresh weight and the height of the plant, but the decreasing rates are different. The highest decreasing rate is happened in the second treatment. The correlation coefficient is 5 % comparing to other treatments. The dominant fungus of the soil in the third treatment cause a little increase of fresh weight and the height of the plant.3.The dominant fungus of the soil restrain the germinating tendency of the soybean after treated by the soil fungus toxicant liquid no matter what kinds of soybean varieties and what kinds of treatments, the germinating ability of the untreated soybean seeds are much better, there are some differences in different treatments and different varieties, the restraining effect of the germinating ability in the second treatment is the strongest, than the third treatment ,the first treatment ,the fourth treatment is the weakest.4.The dominant fungus of the soil restrain the radicle growing of the soybean after treated by the soil fungus toxicant liquid no matter what kinds of soybean varieties and what kinds of treatments, the radicle growing of the untreated soybean seeds are much better, there are some differences in different treatments and differentvarieties.S.The most dominate fungus in soil are Fusczrium semilctum and Fu.sarium oxyspoium. After inoculating to soybean root by these two fungus, root rot was aggravating with increasing inoculate time. 40 after being inoculated, all treated soybean tap roots appeared serious disease with symptoms of turning brown and black, partly or wholly rottening.6.The secretion of Fusarium semilctum and Fusarium oxysporium which extracted by non-hydro ethanol significantly inhibited the soybean germination by 50%. Moreover, these secretion also caused embryo withering and brown, unhealthy radicles and seedling.7.Sterilizing of continuous cropping soil could effectively relieve soybean of continuous cropping hindrance. Unsterilized soil, however, lead to classical hindrance performance with yellow and some mosaic cotyledon, and high infection rate up to 56.7%. It showed that sterilizing of continuous cropping soil can eliminate the disadvantageous factors which influence soybean growth, then make soybean growth healthy.