Final answer:
To find the revolution time to apply 1 inch per turn net, calculate the volume needed for the 108-acre field, adjust for distribution uniformity and pre-infiltration losses, convert the volume to gallons, and divide by the flow rate of 986 GPM.
Step-by-step explanation:
To calculate the revolution time that applies 1 inch per turn net to the crop for a center pivot system, we first need to consider the area of the field and the system's flow rate. We have an area of 108 acres and a flow rate of 986 GPM (gallons per minute).
To convert acres to square feet, we use the conversion factor that 1 acre is equivalent to 43,560 square feet. Therefore, 108 acres is equal to 108 * 43,560 square feet.
Since 1 inch is 1/12 of a foot, to apply 1 inch per turn net across 108 acres, we need to distribute 108 * 43,560 / 12 cubic feet of water. However, we must also account for distribution uniformity (DU) and pre-infiltration losses. With a DU of 0.83, we will need to increase the volume of water to compensate for the uneven distribution. Similarly, with a 6% pre-infiltration loss, additional water is needed to ensure the net application is 1 inch per turn.
To find the volume in gallons, we can use the fact that there are 7.48052 gallons in a cubic foot. After calculating the appropriate volume of water, considering DU and pre-infiltration losses, we can then use the flow rate to find the time for one revolution. This is done by dividing the adjusted volume (in gallons) by the actual system flow rate (in GPM).
By performing these calculations, we can determine the time in minutes that it takes for the system to make one complete revolution and apply 1 inch of water net to the crops.