Manure has become a minor sourceof nitrogen in all major agricultural countries.
在主要的农业国家动物粪便已经不是氮肥的主要来源。
2
The liquid manure is still a major sourceof environmental pollution, although the way of separating solid and liquid manure reduces the environmental effect in certain extent.
During the time of traditional agriculture in Guangdong, the main manuresourceof mountainous areas was ash, while in the plains, the main manuresource was the river filth.