The introduction of pig feed in the past and the flood of water hyacinth

Introduction: affected by the rare "high temperature" weather, since January 8, the water level of Huangpu River and Suzhou River has experienced the phenomenon of "flourishing" of water hyacinth The reporter learned from the municipal waste disposal company that over the past few days, they have sent 12 machines to sweep the ships every day and carried out fishing without interruption Only the day before yesterday, 225 tons of water hyacinth were fished out, which has doubled the average fishing volume in the growing season of water hyacinth! Looking from the flood control wall of the Bund, the reporter found that although the temperature had dropped sharply, there were still many "leaky nets" of water hyacinths floating on the water surface in this area Some of them began to rot, rippling along with the river, which made the scenery worse According to the city appearance and Environmental Protection Bureau, water hyacinths used to disappear in November and February From this year to the middle of January, water hyacinths are still so "prestige", which is rare in history It is understood that in recent years, water hyacinth has frequently "visited" the Huangpu River and Suzhou River Basin, the root cause is that the eutrophication of the water environment in the Taihu Lake Basin has not been fundamentally reversed The water hyacinth consumes a lot of dissolved oxygen in its growth, which aggravates the eutrophication of water body; the water hyacinth which is too late to be salvaged sinks to the bottom of water after decaying, and becomes the "fertile soil" for the growth of aquatic plants in the next year, causing a vicious circle Water hyacinth is becoming more and more fierce because it is an alien species, and there is no natural enemy to restrict its growth in China When a creature grows in the native environment, it is inevitably restricted by the natural enemies in the biological chain and keeps the ecological balance Once it is moved to a strange place by human, it may lead to ecological disaster Water hyacinth was introduced from South America to solve the problem of pig feed in 1950s With the development of feed industry and the change of pig feeding mode, the input and output of water hyacinth feed with high water content and less edible ingredients are not in direct proportion Therefore, the water hyacinth that everyone competed for in the past is now alienated into the environmental pollution that cannot be avoided If the introduction of alien species leads to ecological disaster, it is far from a water stop gourd In the coastal area of Fujian Province, in order to protect the seawall and use it as feed fuel, rice grass was introduced from the United States in the 1960s Unexpectedly, it has a very strong reproductive capacity and extremely developed root system, which soon developed to the beach covering 140000 mu, causing devastating impact on fish, shrimp, shellfish and other aquatic products It is easier to ask God than to send him At present, domestic scientific research institutions have carried out the research of "exterminating" water hyacinth According to the principle of ecology, its natural enemy, an insect that feeds on water hyacinth, is invited from its mother's home Experiments show that the growth of water hyacinth is inhibited after the natural enemies are put in, but will this insect propagate unchecked, resulting in a new ecological disaster? In view of the previous experience, this study needs to be repeatedly demonstrated Experts believe that at present, the only effective way is to salvage the water hyacinth The lesson of water hyacinth once again reminds people that we must be careful when introducing alien species for environmental management, greening and crop cultivation At present, China is bringing biosafety management into the track of legalization, and this city has also included this into an important part of the government's management work, and the relevant Interim Measures for biosafety management are being formulated and implemented.