Effects Of Dazomet Fumigation And Seaweed Biologic Fertilizer On The Malus Hupehensis Rehd. Seedlings And Soil Microbial Quantity Under Replant Conditions

The experiment was done in the Nation Apple Experiment Center and State Key Laboratory of Crop Biology of Shandong Agricultural University from 2013 to 2014. To clarify the effects of soil fumigation with dazomet and seaweed biologic fertilizer on the young apple seedlings biomass and soil microbial quantities under replant conditions, the Malushupehensis Rehd. Seedlings were selected as the tested material and four treatments were set: replant soil as control(CK), replant soil fumigation with dazomet(T1), replant soil with dazomet fumigation and seaweed biologic fertilizer(T2), replant soil with seaweed biologic fertilizer(T3).The main results were as follows:1. Both the dazoment fumigation and seaweed biologic fertilizer could increase the apple seedlings biomass, and the effect of the combination was the best. Compared with the control, T1, T2 and T3 increased the plant height by 58.68%, 73.32% and 45.32% in July, 27.73%, 48.38% and 13.55% in August, and 37.88%, 54.03% and 9.93% in September respectively. In July, T1, T2 and T3 increased the seedling ground diameter by 10.92%, 35.87% and 2.14% compared with the control, 30.77%, 54.68% and 27.59% in August respectively, 29.58%, 45.82%and6.42% in September respectively. In comparison with the control, T1, T2 and T3 increased the above-ground fresh weight by 98.42%, 158.15%and 50.03%,under-ground fresh weight by 63.10%, 126.29% and 17.74%, above-ground dry weight by 133.29%, 208.89% and 63.75%, and under-ground dry weight by 105.70%, 120.54% and 32.08% in August.2. Dazomet fumigation, seaweed biologic fertilizer and the combination improved the root respiration rate, the activities of CAT, POD and SOD in root of the apple seedlings. The effect of the combination was more obvious than that of the others. Compared with the control, T1, T2 and T3 improved the apple seedlings root respiration rate by 15.12%, 38.99% and 21.05%,the activity of SOD by 26.02%, 35.87% and 10.22%, the activity of POD by 60.00%, 110.77% and 21.54%, the activity of CAT by 265.62%, 409.38% and 184.38%, respectively.3.Compared with the control, dazoment fumigation and the combination improved root total length, surface area, volume and tips of apple seedlings. Among them, the four root configuration parameters of T1 were respectively increased by 12.52%, 48.70%, 106.86% and 70.73% compared to the control. The four root configuration parameters of T2 were respectively increased by 41.11%, 79.81%, 130.15% and 151.31% compared to the control.4.Dazoment fumigation reduced the number of bacteria and fungi by 58.25% and 70.88% in the soil, respectively. Seaweed biologic fertilizer increased the number of bacteria and fungi by 666.75% and 145.88% in the soil. The combination increased the number of bacteria, reduced the number of fungi, as a result the ratio of bacteria and fungi increased by 1009.44% compared to the control.