Proper Fertilizer and Soil Amendment Procedures Reduce Risk
The Almond Board of California does not support the use of manure as fertilizer, but if used, the manure must be applied properly.
Using a readily available resource such as animal waste for improving soil fertility generally makes sense. It’s typically economical and easily accessed. However, carefully controlled research studies have demonstrated the potential for the almond kernel to be at risk of contamination during windrowing and sweeping.
Using non-composted manure (mixtures of feces, urine, and other organic matter) increases microbial risks on the farm and could contribute to food-borne illness. Stacked and aged manure is not the equivalent of well-managed compost and is known to have a greater potential to harbor surviving pathogens.
If manure use is an integral part of your operation, at a minimum, you should adhere to the following recommendations:
- Use composted manure; ensure that stacked manure reaches 131-140 degrees at a depth of 18-24 inches for at least three days prior to use. If using a supplier obtain a certificate of analysis that the product has been composted and tested for pathogens
- Manure should not be applied to almond orchards during the growing season; apply after harvest and incorporate into the soil immediately to accelerate pathogen die-off
- Store manure away from areas where almonds are grown and handled; erect physical barriers and/or diversion buffers to prevent run-off and drift
- Maintain detailed records of all applications
The intimate and extended contact harvested almonds have with the orchard floor demands that all practical steps to minimize the intentional introduction and survival of human pathogens in soil must be taken.
Standards for composting are regulated by the California Integrated Waste Management Board (Title 14, California Code of Regulations, Section 17868.3).
Resources for industry standards and testing are available from the US Compost Council.
Additional information and access to GAP resources about manure use and pathogen survival in soils are available from the University of California, Davis. For specific information about microbial food safety, click here.
Guide to Minimize Microbial Food Safety Hazards for Fresh Fruit and Vegetables