Study Of The Soil Environmental Behavior And Effect To The Soil-Borne Pathogens After Application Of 1,3-Dichloropropene

Soil-borne diseases are a type of disease caused by the infection of plant pathogens in soil when the environment is appropriate. Soil-borne diseases are strong infectiousness and good hideness. It'll be very difficult to control when it happens. The soil-borne diseases become more and more serious after 3-5 years'cultivation of plants. It'll affect the yield and quality seriously. The yield loss may be 20%-40% generally or go up to 60%, even no harvest. With the enlarging of the areas of greenhouses and continuous cultivating of high value crops, the diseases caused by soil-borne fungi and nematodes become a predominant issue. Using the fumigants to soil disinfect is the most economical and effective method now. methyl bromide(MB) is the traditional fumigant used to soil fumigate.But as a stratospheric ozone depleting compound, it's controlled in the Montreal Protocol and will be phased out in China in 2015.So finding new fumigants and technology to control soil-borne diseases has very important theoretical meanings and practical application worth.1,3-dichloropropene(1,3-D) is a potential alternative to MB.The objective of this study was to make sure the feasibility and the best spread application formulation of 1,3-D through determining the distribution,emission, leaching, and residual after the 1,3-D and 1,3-D capsule applying in soil columns and evaluating the efficacy of 1,3-D to the soil-borne pathogens through the indoor experiment and field trials.(1)The result of determining the distribution, emission, leaching, and residual of 1,3-D after different treatments in soil columns showed that 1,3-D has good penetrability, can diffuse to the 20 cm above and 30 cm below the applied depth; When the soil surface was irrigated during the first 4 days,1,3-D soil gas concentration was higher than other treatments at depths below 20 cm, but lower at 0-15 cm depth. The application of 1,3-D capsule relatively reduced total 1,3-D emission by about 14% and max emission flux by about 50% compared to liquid injection with film tarp, and total 1,3-D emission was only 0.13% for 1,3-D capsule application with 4 days'irrigation with no tarp.The results indicated that 1,3-D capsule or irrigation can reduce the emission and the pollution to the environment. The concentration of 1,3-D in the leachate collected from the 4 day irrigation with no tarp treatment was lower than the LOD.The residue of 1,3-D in soil was not detectable at the end of each column experiment, exactly 32 days after fumigation. This indicated that 1,3-D had degraded in the soil within 32 days.(2)The results of indoor biological efficacy experiment of 1,3-D liquid and capsule showed that both 1,3-D liquid and capsule have good effect to the Fusarium spp. and nematodes in the columns. At the range of 20 cm above and 10 cm below of the applied depth,1,3-D liquid injection, the decline rates were above 90% to the nematodes and above 70% to the Fusarium spp.;1,3-D capsule, the decline rates were above 80% to the nematodes and above 60% to the Fusarium spp.(3) The results of field trials of 1,3-D liquid injection showed that the decline rate of 1,3-D liquid 10g/m2 to the nematodes was above 90%, it was also above 70% during the period of harvest. The decline rates of 1,3-D liquid 20g/m2 to the Fusarium spp.and Phytophthora spp.were above 60% and 50% respectively. Tomato yields treated with 1,3-D liquid were significantly higher than that in the CK, the yield rates were all above 250%. There was no significantly difference in tomato yields between 1,3-D liquid 20g/m2,40g/m2 and MB 50g/m2.(4) The results of field trials of 1,3-D capsule showed that there were no significant differences of the control effects to the soil-borne fungi and nematodes between 1,3-D capsule and 1,3-D liquid treatments, the decline rates were all above 70%. The control effects of 1,3-D capsule to the Fusarium spp. and nematodes in soil were better than 1,3-D liquid injection during the period of harvest, the decline rates were above 80% and 70% respectively. The two treatments both had good control effects to the root-knot of tomatoes. Crop yields in plots treated with 1,3-D capsule and 1,3-D liquid were significantly higher than those in untreated control, the yield rates were both above 10%.(5) The complex study confirms that both 1,3-D liquid and capsule can control the nematodes effectively and level of control the soil-borne fungi.It can be promoted and used as a new fumigant. The 1,3-D capsule formulation is applied convenient and can reduce the emission of the 1,3-D to the atmosphere compared to the 1,3-D liquid. It is more secure to the stuff and environment around and can be the more widespread application formulation.