New standing crop biomass added to an environment over some period of time.
Standing crop biomass is accumulated net primary productivity. That is, it is the primary productivity, as measured in terms of , that is left over within an ecosystem given losses to metabolism.
That metabolism is as seen in both primary producers and and thus net ecosystem production technically includes the biomass of consumers as well. The latter are particularly important in aquatic biomes where primary producer biomass tends to be low due to high turnover times.