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Beijing and Nanchang in Jiangxi Province, respectively, in 2004, April 10 and April 20 to 23 held twice Soil and Fertilizer Symposium. The conference theme will focus on the quality of soil, fertilizer and pollution-free agricultural relations, the market and the use of fertilizers and so on.
Ministry of Agriculture in April 2001 the country launched the "pollution-free food action plan", the current focus is to grasp the quality and safety of the "basket" of goods and agricultural exports. According to the national standard, "the quality and safety of agricultural products pollution-free vegetable safety requirements" (GB18406.1-2001) and "pollution-free fruit quality and safety of agricultural safety requirements" (GB18406.2-2001), fertilizer chromium, cadmium, mercury, arsenic, lead Six kinds of heavy metals and harmful elements of fluorine have been limited, and there are also limited requirements for nitrite and nitrate. In addition, there are maximum residue limits for 42 pesticides and 22 pesticides in vegetables. There are 3 issues to be aware of.
1. From the perspective of heavy metal content, chemical fertilizers are much "clean" than organic fertilizers.
At the same time, the content of zinc, copper and arsenic in livestock and poultry excreta in large-scale farms is very high, probably from feed additives. Therefore, the pollution of heavy metals mainly comes from organic fertilizers.
2. The content of cadmium (Cd) in imported phosphate fertilizer is worthy of attention.
The cadmium content in phosphate rock and phosphate fertilizer in China is relatively low. In addition to the Kola phosphate mine in Russia, the cadmium content in phosphate rock and phosphate fertilizer is significantly higher than that in China.
3. The accumulation of nitrate in vegetables and fruits is affected by many factors, mainly related to the type of vegetables (internal factors) and the amount of nitrogen fertilizer (external factors), which cannot be attributed solely to the application of nitrate nitrogen fertilizer. Vegetables are hi-nitrogen crops, and it is necessary to apply proper amount of nitrate nitrogen fertilizer. This point has gradually reached a consensus.
The development and development of new fertilizers is a hot topic at these two conferences, but the actual research and the scale production that can be achieved in a short period of time are few. In addition to slow/controlled release fertilizers, organic-inorganic compound fertilizers, multi-functional fertilizers and new types of bacterial fertilizers, there are also people who propose nanostructured fertilizers and nanomaterial coated fertilizers. It is said that the fertilizer effect of poorly soluble materials such as CaCO3 and Fe2O3 can be improved, and the nanomaterial coated fertilizer can make it a slow release fertilizer.
In addition, the National Fertilizer Quality Inspection Center (Beijing) also introduced several types of new fertilizers currently registered: water-soluble fertilizers containing medium-sized elements, such as amino acid calcium; water-soluble fertilizers containing alginic acid; Fertilizers such as chitin (chitin).
According to reports, these new fertilizers have obvious effects on increasing production, but their effective use conditions and methods of use are subject to further testing and verification. (Source: Agricultural Resources Guide, January 11, 2005, 13th Edition Expert Forum)
Much less than the heavy metal content of fertilizers organic fertilizer
Sinochem Fertilizer Company Senior Advisor, Chinese Academy of Agricultural Sciences Soil and Fertilizer Lin Bao
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