Garden with Insight v1.0 Help: Plant daily P group
P optimal concentration today: The optimal (best) elemental
phosphorus concentration for this plant today, from an S curve derived
from three 'P optimal fraction' parameters. The plant will try to obtain enough labile P to reach this concentration from the soil layers it has roots in.
P demand for optimal growth today: Plant demand for
phosphorus considering only the plant's optimal P concentration at the current heat unit index as per its 'P optimal fraction' parameters, which are used to
generate an S curve of optimal P concentration vs. heat unit index.
Ratio of P uptake over demand today: The ratio of phosphorus
actually taken up by the plant today to the optimal (best) amount of P uptake today. Used in calculation of
P growth constraint factor.
P demand today: Plant demand for phosphorus from each soil layer considering the plant's
current optimal P concentration, the plant's water uptake (which limits nutrient uptake), and labile P availability in the layer, but not considering competition with other
P supply today: The amount of labile P that would be available to this plant if it were the
only plant in the soil patch. Considers plant root depth, root biomass distribution, and water uptake. Does not consider plant
competition, which affects final uptake.
P uptake today: The amount of labile P actually taken up by this plant today, considering root
biomass distribution over the soil layers, water uptake (which limits nutrient uptake), and competition
between plants in the same soil patch.
P in live plant biomass: The total amount of elemental
phosphorus in the living parts of the plant.
P in standing dead biomass: The amount of elemental phosphorus in standing dead biomass for
this plant, or biomass that has died but has not yet fallen to the soil. This P is leached to the top soil layer
(and enters fresh organic P) when it rains and when the soil is mixed.