The situation of pesticide residues in orchards is relatively common. The key to reducing the content of pesticide residues is to eliminate pollution, especially pesticides and soils. To control pesticide residues, in addition to using pesticide rapid-detection instruments to strictly test the quality of vegetables and fruits, it is also necessary to improve and clean the soil. 1. The distribution of BHC residue in the surface and deep soils of the orchard soil is relatively consistent, and it is close to the background soil residue; the surface residue of DDT in the orchard soil is significantly higher than the deep layer, and is much higher than the background soil; the DDT in the surface soil of the orchard The residue is higher than BHC. These indicate that the BHC pollution in the soil was mainly caused by the past (before the 1970s), and the current residue is already very low; and the DDT pollution is mainly caused by the recent spraying (in the 1980s) of dicofol (containing 5% to 10% DDT). (Chen Zongxi 1995), although it has long been banned, it will remain in the soil for some time. The key to reducing the amount of residues is to eliminate new sources of pollution. For the orchard soil that has been contaminated, the key part of the residual amount is reduced to the topsoil. 2. The orchards of different fruit and vegetable varieties had little difference in BHC residues, and there was a large difference in DDT residues and there were certain rules. That is to say, the DDT residues in the soils of rare and valuable varieties Tieguanyin, Benshan, and Huangmuyan were higher than those in ordinary varieties, indicating that they were valuable. The amount of pesticide sprayed in the variety garden was more than that of ordinary orchards, but the pesticide residues in the leaves of vegetables and fruits showed opposite laws. Does this indicate that Tieguanyin and Huangmuyan are weak in their ability to absorb pesticides or have a strong ability to degrade pesticides, and remain to be further studied. 3. The mathematical model fitting results of pesticide residues and related factors in orchard soils of all varieties and varieties showed that there was a relationship between soil pesticide residues and soil depth, altitude, and tree age of fruits and vegetables. The regularity of the performance of different species is not consistent, but the general trend is that the deeper the soil, the higher the altitude, the greater the age, the lighter the degree of pollution of pesticides. This can be used as the basis for choosing a pollution-free vegetable and fruit leaf base. 4. Residues of DDT in leaves of fruits and vegetables were significantly higher than those of BHC, and the natural degradation of BHC had reached a relatively low level; there was a certain relationship between BHC residue in leaves of fruits and vegetables and tree age, elevation, and BHC residue in soil, among which the age of the tree and the soil of the top layer There was a significant negative correlation and positive correlation between BHC residues and BHC residues in fruits and vegetables. DDT did not have such a significant relationship. 5. Compared with vegetables and fruits, BHC mainly remains in the soil, DDT mainly remains in the tree body; BHC distributes evenly in fruits and vegetables and soil, and the difference is small. DDT shows a difference in the distribution of fruits and vegetables and soil. With. Sparse flowering, proper tender mining, and picking of fruit and vegetable during processing will play a role in reducing residuals. Disposable Face Mask,Disposable Sterile Face Mask,Medical Surgical Mask,Medical Disposable Face Masks Jiangyin Huashi Medical Equipment Co.,Ltd , https://www.medicaldevicemask.com
March 28, 2023