Dry-sanding fermentation beds are considered safer and more effective for pig farming. The process involves the use of powerful microbial strains that thrive in specific conditions, such as rice bran as a carrier with a moisture content of around 65%. However, during operation, it's important to note that litter doesn't need to be watered, and these beneficial microorganisms require precise moisture levels. Let’s take the Jinbao fermentation bed as an example to better understand this concept.
In the Jinbao system, the sawdust layer is typically only 50 cm thick, with a moisture content of exactly 65%, which is essential for the proper functioning of the bed. Unlike traditional methods, no additional water is needed—just the right mix of microbial cultures. But where does the moisture come from?
First, let’s look at the sources of moisture:
1. **Sawdust itself**: Fresh sawdust, like that from Chinese fir, eucalyptus, or other hardwoods, naturally contains some moisture. Depending on the type of wood, the moisture content can range between 30% (for dry sawdust) and up to 60% (for freshly processed wood).
2. **Pig waste**: Pig feces and urine contribute significantly to the moisture level. On average, each pig produces about 4 kg of excrement daily, with a water content of roughly 60%. For a 20-square-meter bed housing 15–20 pigs, this amounts to around 60 kg of water per day—substantial enough to maintain the required moisture without adding any extra.
3. **Other sources**: Residual water from drinking, feeding, or rain can also contribute, but these are minor and should be managed carefully to prevent over-saturation.
Secondly, not adding water is actually safer and more efficient. Since moisture comes naturally from the sawdust and pig waste, there's no need for manual control. If too much water is added, the moisture level could exceed 65%, leading to poor microbial activity or even death of the beneficial bacteria. This would render the fermentation bed ineffective. On the flip side, if the moisture is slightly low, the microbes can go dormant or slow down their activity, but they will reactivate once the right balance is restored.
Therefore, maintaining a dry-sanding fermentation bed is not only more practical but also more sustainable and safe. It reduces the risk of overwatering, ensures consistent microbial performance, and ultimately improves farm hygiene and economic returns.