| The quality and safety of agricultural products concern millions of households.Ensuring the quality and safety of agricultural products is not only the main content and basic guarantee of food safety,but also an important task of realizing rural revitalization.In recent years,although our country agricultural product quality safety supervision level rising,but still produce quality safety accident to happen from time to tome,predominantly pesticide safety hazard factors is still difficult to control,are the main reasons why agricultural product quality safety traceability system in our country at present is still not perfect,mainly scattered planting behavior still need to further standardize the production,Pesticide residue control measures in vegetables haven’t been effectively implemented.Taking Shanwei city of Guangdong Province as an example,based on the investigation of pesticide use behavior in vegetable planting process,the influence of different growth factors on pesticide residues in vegetables was studied through detection and analysis,and the removal effects of different cleaning methods on pesticide residues were preliminarily compared.It provides some reference for the establishment of vegetable safety control measures.The main contents of this paper are as follows:(1)Survey on pesticide use behavior in vegetable planting process.Through sampling questionnaire survey of vegetable farmers in Shanwei city,Guangdong province,the behavior and habits of pesticide use and awareness of agricultural product quality and safety were investigated.The results showed as follows:(1)The vegetable farmers in Shanwei of Guangdong province were generally older and less educated.More than 80% of the vegetable farmers surveyed said: kale,pakchoi,mustard and other varieties of insect pests are serious,need to use pesticides regularly,and the combination of several pesticides is relatively common;The pesticides used by vegetable farmers to control insect pests generally choose acetamiprid,imidacloprid,aminoabamectin benzoate,etc.,carbendazim,chlorothalonil,etc.,for the prevention and control of grass damage,choose enoxone,quinacrine,etc.During the rainy season,more than 65% of vegetable growers believe that the frequency of pesticide spraying needs to be increased,while 60% of vegetable growers believe that the rainy season can reduce the safe interval after spraying by 2-3 days.(2)In the survey on the awareness of agricultural product quality and safety of vegetable farmers,it was found that in the process of pesticide application in vegetable planting,73% of vegetable farmers said that the safe interval of vegetable drug use was controlled only by experience,and more than 57% of vegetable farmers didn’t have the habit of recording production;The proportion of vegetable farmers who have studied the Law on the Quality and Safety of agricultural products is only about 7%;More than 90% of the surveyed vegetable farmers don’t have the conditions for self-testing,and about 83% of them are willing to cooperate with government departments for sampling testing.As for the supporting implementation of the "certificate of Edible Agricultural products" system,more than 50% of the surveyed vegetable farmers expressed support and cooperation,but the operating cost should be considered.(2)Analysis of factors affecting pesticide degradation in vegetable planting process.By simulating planting environment and the use of artificial simulation of rainfall device,research different vegetable varieties,applying pesticide content and natural factors such as rainfall and the production behavior of chlorpyrifos,chlorothalonil,effective chlorine fluorine with ester,imidacloprid,olefine ketone and organism worm amidine 6 kinds of pesticide residues,by gas chromatography and liquid chromatography-mass spectrometry determination of pesticide residues,ia And data analysis.The results showed that:(1)After a daily rainfall of 20 mm,the degradation degree of different vegetable varieties was as follows: Cabbage ≈ Tomato > cucumber > kale > scallion > pakchoi.It was obvious that pesticide residues in pakchoi,kale and scallion weren’t easily degraded,and the pesticide residues in pakchoi were the most significant,so pakchoi was used as the test variety.(2)after applying pesticide varieties and different content,0 d,3 d,5 d,7 d,after 9 d of interval number,imidacloprid,organism worm amidine and pesticide residues of chlorothalonil are declining as interval number,and no more than the national standard maximum residue(called simply MRL)and chlorpyrifos as restricted use pesticides,pesticide residues than called simply MRL,The pesticide residue values of allyl ketone tended to zero,which was very different from MRL and could be ignored,while the application amount of betacyhalothrin at different concentrations could be reduced to below MRL only after 9 days.(3)Within 60 h,different rainfall frequencies were set and the daily rainfall was 15 mm/ time.Degradation degree: 10 times /60 h>6 times /60 h>4 times /60 h≈3 times /60 h≈2 times /60 h,it can be seen that rainfall at the frequency of 6 times /60 h and 10 times /60 h is the main influencing factor of pesticide degradation in vegetable planting process.(4)The decreasing degree of rainfall in different days is as follows: 80 mm>40 mm>20 mm>5 mm> 0 mm,and the change of pesticide residues was the most significant under daily rainfall of 40 mm and80 mm,which was the main influencing factor of pesticide degradation during vegetable planting.(5)the use of low-toxic pesticide aminoabamectin benzoate,the interval is one day when the pesticide residue is 0.101 mg/kg more than MRL(0.1 mg/kg),and the interval is three days when the pesticide residue is 0.025 mg/kg much lower than MRL,therefore,the use of low-toxic pesticides in vegetables,Only when harvested after a reasonable interval can residual indexes meet safety requirements.(3)Analysis of the removal effect of pesticide residues by different cleaning methods.With common cabbage as test samples,respectively the soak with water,fruit and vegetable detergent auxiliary cleaning methods such as immersion,ultrasonic,by gas chromatography and liquid chromatography-mass spectrometry of chlorpyrifos ia,chlorothalonil,effective chlorine fluorine with ester,imidacloprid and organism worm amidine 5 kinds of pesticide residues were determined,testing different cleaning method to remove effects.The results showed that:(1)For chlorpyrifos and other pesticides banned by the state,all the cleaning methods couldn’t effectively reduce the pesticide residues,and the pesticide residues were higher than MRL(0.02mg/kg);(2)Under different soaking time,the removal effect of pesticide residues was relatively better with the longer soaking time,and the removal effect is: 90 min>60 min>30 min>0 min,and the effect gradually became obvious at 60 min.(3)Under the different cleaning solutions,the removal effect is: solution > water immersion>soda solution > rice washing water starch.It can be seen that starch solution has a relatively better effect on removing pesticide residues in vegetables.(4)Under different commercial fruit and vegetable cleaning agents,the removal effect was as obvious as water immersion,but in the removal of chlorothalonil pesticide in ordinary cabbage,the removal effect of the two domestic fruit and vegetable cleaning agents was more significant;(5)There was little difference in pesticide residues between ultrasonic-assisted soaking and water soaking,and no significant difference in removal effect.(6)Under the comparison of two different vegetable varieties of pakchoi and kale,kale is easier to remove pesticide residues than pakchoi. |
