Percent Of Deficits Research Articles

The effect of water saving and production increment by drip irrigation schedules

Drip irrigation system can achieve high uniformity. When the system is designed for uniformity coefficient equal or more than 70%, the water application in the field can be expressed as a normal distribution and further simplified to a linear distribution. This paper will describe the irrigation scheduling parameters, percent of deficit, application efficiency and coefficient of variation by simple mathematical model. Using this effective model and the irrigation application, the total yield affected by the total water application for different uniformity of irrigation application can be determined. More over, this paper uses the cost of water, price of yield, uniformity of the drip irrigation system, crop response to water application and environmental concerns of pollution and contamination to determine the optimal irrigation schedule. A case study shows that the optimal irrigation schedule can achieve the effect of water saving and production increment compared with the conventional irrigation schedule in which the whole field is fully irrigated.

Linearized Water Application Function for Drip Irrigation Schedules

ABSTRACT Alinear cumulative frequency distribution function can be used as an approximation of the accumulated frequency S-curve determined from a normal distribution. The straight line function can be used to describe the irrigation scheduling parameters; percent of deficit, application efficiency and coefficient of variation by simple mathematical equations. Furthermore, a mathematical optimization can be developed to determine optimal water application based on irrigation system's uniformity, a reduction coefficient of a known crop under deficit irrigation situation, cost of water and the return of the crop yields.