After fermentation, organic fertilizer should have a faint, humus-like aroma. If it has a pungent odor, it not only affects the environment but also indicates incomplete fermentation, which can affect fertilizer efficiency and even burn crop roots. This is a common problem in organic fertilizer production. In fact, off-odors are mostly caused by insufficient fermentation, imbalanced proportions, or improper environment. Mastering the correct methods can easily solve this problem in organic fertilizer production.
First, identify the source of the odor. There are two main types: one is an ammonia smell, often caused by excessive nitrogen fertilizer in the fermentation raw materials (such as a high proportion of poultry and livestock manure or soybean meal), producing excessive ammonia gas during decomposition; the other is a putrid smell, stemming from oxygen deficiency during fermentation, leading to the proliferation of harmful anaerobic bacteria and causing the raw materials to rot and spoil. Identifying the root cause is crucial for effective treatment.
For an ammonia smell, the most direct method is to supplement the carbon source and adjust the carbon-nitrogen ratio. Add sawdust, straw powder, dry soil, or other carbon source materials to the organic fertilizer, mixing them evenly in a 10:1 ratio. Simultaneously, turn the compost pile and ventilate it to allow the ammonia gas to dissipate quickly. If the ammonia smell is strong, a small amount of superphosphate can be sprinkled in to neutralize the ammonia, which can both remove the odor and improve fertilizer efficiency.
If the smell is putrid, the key is to replenish oxygen and kill anaerobic bacteria. The organic fertilizer needs to be thoroughly turned using a compost turner to ensure sufficient air contact between the upper and lower layers. Turn the compost 1-2 times a day for 3-5 days to reactivate beneficial microorganisms. Fermentation agents can also be added to accelerate the decomposition of undecomposed materials, inhibit the growth of harmful bacteria, and eliminate the putrid odor at its source.
Besides remedial measures, prevention is even more crucial. Before fermentation, control the raw material ratio, maintaining a carbon-to-nitrogen ratio of 25-30:1. During fermentation, maintain good ventilation, avoid water accumulation, and control the temperature at 55-65℃ to ensure thorough decomposition. After fermentation, seal and store to prevent secondary fermentation and the generation of odors.
Note that if the odor is accompanied by blackening and stickiness, it indicates that the organic fertilizer has deteriorated and should not be used directly. Fermentation agents and carbon sources can be added again for secondary fermentation and decomposition. By mastering the above methods, you can ensure that fermented organic fertilizer is odorless, highly effective, environmentally friendly, and helps crops grow.
