Described herein are systems, methods, and apparatus for agricultural planting including selecting and varying agricultural input types during an in-field operation. In one embodiment, a method of calculating a volume of a seed during planting comprises adding a known volume of seed to a seed pool that has a fill level sensor. The method further includes dispensing seeds from the seed pool and as the seeds are dispensed, counting the number of seeds with a seed sensor. The method further includes stopping counting when the fill level sensor indicates no seeds present and calculating seed volume by dividing the known volume by the number of seeds counted.