Irrigation Scheduling with Neutron Probe

A simple accurate technique for scheduling irrigation has been developed using a modified neutron probe. The technique uses a graph to display soil moisture content on the dates measured. A best-fit line is drawn through the points and projected to intersect a horizontal refill line to show the date of the next irrigation. Only the correct refill point and the neutron probe measurements are required for correct irrigation scheduling on a field. If one consistent irrigation procedure is practiced on a field, only one neutron access tube is required. Neutron probe readings need to be made about twice each week during hot weather and about one each week during cool weather. Water use by plants, root distribution and extension, and soil drainage are useful byproducts of this irrigation scheduling technique.