According to the core meaning of pollution-free vegetables and green food vegetables, we can attribute the main sources of harmful substances in vegetable products to two: First, fat is a medicine. Fertilizer is the source of nitrate and nitrite in vegetables. Pesticides are the source of pesticide residues in vegetables. Therefore, we must strictly control the application of fertilizers and pesticides.
A density meter, also known as a densimeter, is a device that measures the density. Density is usually abbreviated as either Ï or D. Typically, density either has the units of kg/m³ or lb/ft³. The most basic principle of how density is calculated is by the formula: Ï=m/V Where: Ï = the density of the sample. m = the mass of the sample. V = the volume of the sample. Many density meters can measure both the wet portion and the dry portion of a sample.
Measuring the density and specific gravity at a given temperature, density meters are especially useful when working with viscous liquids or difficult gases. Portable or benchtop densitometers have high storage potentials for easy comparisons of collected data.
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It is currently popular to promote the application of high-efficiency, low-toxic, low-residue pesticides. First of all, we must know that the prohibited pesticides in vegetable production are: phorate (3911), bismuth phosphorus (Suhua 203), parathion (1605), methyl parathion (methyl 1605), and endogenous phosphorus ( 1059), chlorpyrifos, monocrotophos, phosphonamine, methamidophos, isopropoxide, trisulfide, omethoate, zinc phosphide, aluminum phosphide, methylthiophosphorus, methylisophosphorus, Cyanide, carbofuran, fluoroacetamide, arsenic, insecticide, celidine, celia, ulcer, chloropicrin, pentachlorophenol, dibromochloropropane, 401, hexachlorocyclohexane, DDT, chlorine Dan and other high-toxic, high-residue pesticides .
The issue of the security interval. It is necessary to ensure that vegetables are marketed after a safe interval between pesticides. When pesticides are sprayed onto vegetables, no matter how stable they are, there will be complex chemical and biochemical effects under natural conditions and after biochemical effects, eventually losing toxicity. The last time the pesticide is applied to the harvest is to ensure the above changes. The time the process is completed, called the safety interval. The length of the interval is different from the type of pesticide and the season of the crop. For example, the safe interval between cabbage and cabbage is not less than 7 days: 40% dimethoate is ≥10 days, and 90% trichlorfon is ≥7 days. 2.5% cyhalothrin emulsifiable concentrate is ≥7 days, 50% anti-Pu Wei WP is ≥11 days, 40.7% chlorpyrifos emulsifiable oil is ≥7 days, 5% taibao emulsifiable concentrate is ≥7 days, 1.8% The emulsifiable concentrate is ≥7 days, and the 75% chlorothalonil wettable emulsifiable concentrate is ≥10 days.
Use pollution-free new pesticides. Such pesticides are harmless to humans, animals and the environment. Such as plant-derived pesticides such as cucurbitine, matrine, azadirachtin, etc.; biological source pesticides avermectin, agricultural streptomycin, neomycin, jinggangmycin and so on. There are also bactericidal preparations such as Bacillus thuringiensis, Acariciid bacillus, Beauveria bassiana, etc. which are commonly used for many years to prevent and cure chronic diseases such as bacterial wilt and blight.
Pesticide dosage. When using pesticides, the amount of pesticides is easy to produce phytotoxicity, and the effect is not good. Therefore, the application of pesticides should be based on the recommended dosage on the instructions, and cannot be increased or decreased at will. There are two cases of usage: too many uses and too much concentration each time. For example, the maximum number of times of application and the maximum dose per season in cabbage and cabbage are: (the following pesticide formulations are the same as above) Dichlorvos is 5 times and 200 ml/mu, and phoxim is 3 times and 100 ml/mu. Trichlorfon is 5 times and 100 g/mu, cypermethrin is 3 times and 20 ml/mu, anti-èšœå¨ is 3 times and 30 g/mu, chlorpyrifos is 3 times and 75 ml/mu, avermectin For 1 time and 50 ml/mu, chlorothalonil is 3 times and 120 g/mu, and humic acid copper is 4 times and 300 ml/mu.
Use more natural enemies. Protect natural enemies such as ladybugs, spiders, and grasshoppers, create an environment conducive to the survival of natural enemies, and release predators such as predatory mites, parasitic wasps, and red-eye bees.
There is no need for industrial wastewater or domestic sewage. These polluted waters contain metal ions, poisons, germs, and eggs.
Pollution-free vegetables should choose new pesticides