"Ending the damage done by locoweed would be like giving herdsmen a second life," says a herdsman living in the Alxa Left Banner, in north China's Inner Mongolia Autonomous Region, with bitter memories of losing his flock to locoweed poisoning.
Now the herdsman can pin his hopes on a locoweed toxin vaccine developed by a group of Chinese scientists after 15 years of research funded by the Central Government and from Sweden.
Locoweed is seen as the most harmful weed on the grasslands of the United States, Canada, China, Australia, New Zealand, Russia, Spain, Iceland and Egypt, according to Professor Cao Guangrong with the Northwest China University of Agricultural and Forestry Science and Technology based in Xi'an, capital city of northwest China's Shaanxi Province.
After a farm animal eats locoweed, it loses weight until it dies. When locoweed invades grassland, local animal husbandry is seriously challenged.
There are now 44 species of locoweed in the pastures of western China, infesting nearly 100 million hectares altogether, including11 million hectares that are completely useless. Locoweed costs China about 2.8 billion yuan (US$337.35 million) in economic losses annually.
In the early 1980s, about 10 percent of all pastures in western China were affected. However the proportion has risen to more than 30 percent in the past couple of years and is increasing at an annual rate of about 3.5 percent. As it engulfs quality grasslands, locoweed kills more than seven million head of livestock a year in China.
However, the situation is set to change as trials of the vaccine yield positive results.
If an animal is given an injection of loco toxin vaccine, it can eat locoweed and absorb its nutrient content safely. One injection of the vaccine costs about 10 yuan (US$1.2), and lasts one year.
Last year the vaccine was used on a trial basis on some pastures in Qinghai Province and the Inner Mongolia Autonomous Region, according to scientists with the Xi'an-based Shaanxi Yangling Danong Biological Technology Co., Ltd.
No poisoning cases were reported in the whole year in those areas, the scientists said.
Bater, another herdsman in the Alxa Left Banner, injected loco vaccine into 400 heads of sheep in 2001, and in the following spring the sheep which had all survived, gave birth to 756 lambs, double the level of the previous year.
The vaccine, which is independently patented, is regarded as environmentally friendly, as the traditional method of killing locoweed -- digging it out manually or spraying with chemical herbicides -- may result in desertification and pollution.
Locoweed, with its powerful ability to survive, has become an advantageous species for containing grassland desertification. The weed is rich in nutrients, with a crude protein content higher than that of clover, a popular fodder grass.
If locoweed turns out to be useful, it is estimated the area of China's usable pastures will increase by 30 percent and the amount of quality grass for animal husbandry by 50 percent.
(Xinhua News Agency February 1, 2003)
