Silkworm droppings turn out to be an unexpected windfall, and their value should not be underestimated
Since July, in Lezhi County, Sichuan Province, a major cocoon-producing county, an unprecedented novelty has appeared: sericulture farmers who had just sold their silkworm cocoons lined up again to sell discarded silkworm droppings. Silkworm droppings, once worthless, have suddenly become sought after. It is reported that in the county's agricultural and sideline products processing park, a special "park within a park" has taken shape: with silkworm droppings as the main thread, it brings together a series of production enterprises engaged in chlorophyll extraction, feed, fertilizer and biopharmaceuticals, and the output value is expected to reach 1 billion yuan by 2010.
Silkworm droppings can be sold for money
"I never expected silkworm droppings could be sold for money too." On July 25, in front of the silkworm dropping collection point in Tongjia Town, Lezhi County, Sichuan Province, sericulture farmer Tong Mingwang looked especially happy. "I raised three sheets of spring silkworms, and silkworm droppings alone increased my income by more than 130 yuan. I really never imagined it."
"I've raised silkworms for decades, and before @#@250@#@ I could only sell the cocoons, while all the silkworm droppings were thrown away." An elderly man next to him took up the conversation. "Now one kilogram of dry silkworm droppings sells for 0.8 yuan, and everyone thinks sericulture is more @#@3@#@."
It is understood that Lezhi County is a major sericulture base county in Sichuan Province, and its sericulture scale has long ranked among the top in the province. In 2005, the county's sericulture industry rose to second place in the province in terms of egg production and cocoon output, with a total annual output of silkworm droppings approaching 10,000 tons. This item alone can bring farmers more than 7.5 million yuan in "unexpected wealth," increasing the average income of sericulture households by more than 160 yuan.
Extracting chlorophyll
The large-scale purchase of silkworm droppings was organized by a leading silkworm dropping processing enterprise. On July 18, in front of the enterprise's warehouse, the author saw vehicles delivering silkworm droppings lined up in a long queue.
"Silkworm droppings are the feces of silkworms, named for their granular shape, which looks like sand." The enterprise's technical director explained, "Using silkworm droppings to extract chlorophyll not only meets green environmental protection requirements, but is also economically feasible."
It is understood that the main food of silkworms is mulberry leaves, which contain a relatively high chlorophyll content, generally above 15 percent. Because silkworms have a short digestion time, a large amount of chlorophyll is not absorbed and remains in the silkworm droppings, so using silkworm droppings to extract chlorophyll has become one of the preferred commercial production methods. At present, extracting 1 ton of chlorophyll, which sells for 1 million yuan on the market, requires 100 tons of silkworm droppings, and the production cost is about 100,000 yuan. If carotene, which has even higher added value, is further extracted, the cost-to-benefit ratio is at least above 1:20.
"This is the country's first fully automated chlorophyll production line, capable of processing 20,000 tons of silkworm droppings each year, yet it needs only 5 production workers." Pointing to the orderly operating production workshop, the company's boss Zhou Dingzhi was somewhat proud. "Our technological innovation project of 'continuous countercurrent chlorophyll extraction' has already obtained five core patented technologies; the application of high technology has instantly turned silkworm droppings from waste into a favored green treasure."
Extending the industrial chain
"The development of silkworm droppings has powerfully extended the industrial chain and enhanced the overall development scale and comprehensive benefits of the sericulture industry." said Zhao Yongtao, Party Secretary of Lezhi County. The sericulture industry is a traditional advantageous industry in Lezhi, and has already involved 70,000 sericulture households and more than 10 leading enterprises. The deep processing of silkworm droppings has added an important link to the expansion of the sericulture industry. At present, the county has basically formed a complete industrial chain in which upstream farmers increase their income by selling cocoons, silkworm droppings and mulberry branches; midstream enterprises use silkworm cocoons for silk reeling and silk weaving; and downstream enterprises process silkworm droppings to extract chlorophyll, use mulberry branches to press boards, and use mulberries to brew wine.