Different types of fertiliser can be added to blocks by month. Overseer defines a set of products and their nutrients for the major NZ fertiliser companies. If there is not an appropriate product to select from, custom fertiliser and hence nutrient compositions can be created.
How pasture impacts the model
The following diagram depicts what parts of the model the pasture information entered in OverseerFM impacts. For a full interactive view of the scientific model in its entirety please click here
Each pasture block has a pasture type and whether it is grazed (pastoral) or harvested (cut and carry). If the block is grazed runoff characteristics are also required.
Pasture type impacts metabolic energy and nutrient content of pasture and hence uptake of animals. Run off characteristics effect the surface runoff and hence drainage.
Choose dominant pasture type
Use ryegrass if pasture type not available
Use default for hydrophobicity unless you have good reason to change it.
The pasture type provides the model with the ME content and nutrient concentrations of animal feed. This drives the nutrient uptake of the animals and hence nitrogen levels in excreta.
Not all pasture swards or mixes are available in OverseerFM. If your pasture sward is grazed and is not represented on the drop-down menu enter ryegrass/white clover. It is recommended that you chose the dominant pasture type in the block.
As described, ME from pasture production is driven by the animal numbers and existing supplementary feed. Therefore, if animal numbers and supplementary feed remains the same but pasture type changes, the ME requirements are unchanged, but DM and nutrient intake may change.
The runoff characteristics affect the nutrient runoff from the block.
Naturally high water table: Is used in riparian/wetland model, does not affect hydrology and hence losses from block.
Compacted: Soil water contents in top layer is reduced if soil is compacted.
Hydrophobicity: Describes the susceptibility of waterto infiltrate or runoff at the soil surface. Is used in hydrology model to define runoff. Default is based on region and rainfall.
Propensity to pugging: This is not a measure of whether pugging has occurred, or the degree of pugging that occurs after a single grazing event but rather the propensity of pugging. This is used to estimate the profile drainage status, and in the estimation of denitrification.