Methods of calculation and data sources
What the application computes, by which formulas and on the basis of which publications. Every section follows one order: purpose, input quantities with units, formulas, constant values, range of applicability.
Direct solar radiation and shading
Duration of direct solar illumination of a bed over a day, and the share of the daily direct-beam flux that reaches it in the presence of shading objects.
Accumulated temperature and seasonal shift
Heat accumulated in the current year, the date of a sustained transition through a temperature threshold, and the shift of the season relative to the multi-year mean.
Degree-days to harvest
Accumulation of effective degree-days from the planting date to a value measured for a cultivar in field trials, and the date on which the plot reaches it.
Narrowing plant problems by observed signs
Narrowing the list of possible problems for a crop by observed signs. No diagnosis is made: the number of matched signs and the source description are given.
Frost threshold and critical bud temperatures
The temperature below which the coming night is called dangerous for a particular planting. The threshold comes from one of three sources, and the source is stated alongside the value.
Time to emergence from soil temperature
The number of days from direct sowing to emergence at the measured soil temperature. The value is taken from a published table; nothing is computed between its columns.
Evapotranspiration and the soil water balance
Daily water use by a planting and the store of available water in the root zone.
Soil classification
Texture by the USDA triangle and soil type by the World Reference Base — two independent characteristics used in different ways.
Infection conditions: late blight and apple scab
Published criteria relating temperature and wetness to the possibility of infection. What is computed is the fulfilment of the conditions, not the occurrence of infection.
Storage conditions and keeping time
Temperature, relative humidity and expected keeping time from the commodity summaries of Agriculture Handbook 66, together with ethylene compatibility.
Treatments: pre-harvest interval, repetition and hazard to bees
Quantities arriving with a row of the plant protection register, and the three statements that follow from them.
Fertiliser estimate
A bed's requirement for nitrogen, phosphorus, potassium and lime: what comes from fertilisation guides and what remains the app's own estimate.
Nutrient removal with the harvest
How much nitrogen, phosphorus and potassium leaves the bed with the harvested produce.
Crop compatibility: state of the evidence
The list of pairwise relations between crops and the result of checking each against the literature.
The application shows the same reference beside the statement itself, through the button next to the figure. This section collects the full account rather than replacing it.