What is the difference between NMP, CNMP, MMP?

NMP = nutrient management plan; CNMP = comprehensive nutrient management plan; MMP = manure management plan.

These acronyms are regulatory distinctions of nutrient management plans depending on the size of dairy and the state where it’s located. Generally, a CNMP applies to CAFOs – though some smaller farms need one depending on how they handle manure. NMPs will be the most common; generally applicable to most size dairies above a certain threshold. MMPs vary – some states have them for smaller dairies, though not necessarily required by regulation. For example, this is how it’s broken down in PA: https://extension.psu.edu/programs/nutrient-management/manure/understanding/what-type-of-plan-do-you-need-for-your-farm

How should one differentiate between “liquid/slurry without a natural crust” and “uncovered anaerobic lagoon”? Is it dependent on whether the solids are above or below 5%? Or is it dependent on some type of stabilization and treatment with water being deliberately added?

The 5% solids cut-off is a good rule of thumb for many situations. However, it is correct that the best distinction of an anaerobic lagoon is one where there is some treatment and deliberate water addition (ie. If we flush the manure out of the barns, if we add water to vacuum it, if we do SLS, etc.). In a case where the only water added is rainwater and maybe wash water (not flush water), the manure pit is likely best described as a slurry.

A farm that uses solid-liquid separation has multiple uses for the manure solids after in-vessel composting (windrow composting, solid off-farm, and bedding). Should all of that be taken into consideration or should it all be considered as going through the in-vessel composting?

We only have the option to specify 2 management strategies for the solid fraction after SLS, so there isn’t a perfect answer to match the farm’s situation. If we could enter more than 2 strategies, we could capture all 4 of the above and weight them by the amount of time (in-vessel composting, windrow composting, sold off-farm, and bedding) – but since we can only do 2, I would focus on those where the manure spends the most ‘time’ of the year, e.g. bedding and sold off farm.

How do you handle compost barns as manure management system?

We would recommend using ‘deep bedding with storage > 1 month’ as a proxy for a compost barn system. The FARM ES model does not list ‘compost barn’ as an option because there is currently insufficient research available on the GHG emissions from compost barn systems.