1. A system for agricultural monitoring and prediction, said system comprising: a first reporting agent configured for reporting aerial data representing relative measurements of an agricultural metric in a geographic area, the relative measurements having an unknown bias; a second reporting agent configured for reporting ground-based data representing absolute measurements of the agricultural metric for a portion of the geographic area; and a database configured for storing said ground-based data and said aerial data along with other farming data for a wide geographic area; and a processor configured for accessing the database and using said ground-based data for the portion of said geographic area to calibrate said aerial data, thereby synthesizing absolute measurements of the agricultural metric for said geographic area from said aerial data, wherein said synthesizing absolute measurements further comprises: using a plant growth model to propagate said ground-based data forward or backward in time as needed to compare it with non-contemporaneous aerial data, wherein said processor is further configured to generate a prescription for an application of chemicals to an agricultural field based in part on said synthesized absolute measurements, and wherein a physical crop treatment applicator is configured to apply said chemicals to said agricultural field based on said generated prescription for the application of chemicals.