Line Source of Water Application - An Appropriate Drip Irrigation System for Field Crops

Drip irrigation system is generally adopted in widely spaced row crops by providing point source(s) of water application to individual plants. Its adoption for closely spaced field crops requires drip laterals to serve as line sources of water application. Widths. Of wetted strips under laterals having emission rates of 8, I 0,12 and 16 Lph/m were observed under durations of operation of I, 2 and 3 hr, in a sandy loam soil. The wetted widths, in all the line sources were found increasing almost linearly with time as well as with increasing emission rates. A prediction equation (S = 6.914 + 6.70T + 2.786 q) was developed for determining the spacing between two adjacent laterals, S (em) for a known operation duration, T (up to 3 hr) and emission rate of the laterals, q (ranging between 8 to 16 Lph/m)

Spatial and Temporal Variability of Manning\u27s n In Irrigation Furrows

Manning\u27s roughness coefficient, n, as a property of space is found to be variable. But its variability is assumed as insignificant in the design of irrigation systems. However, the variability may affect the performance of irrigation, particularly the distribution efficiency. Therefore, an understanding of the statistical behaviour of the variability of n in space and over the crop season may help in improving the models of irrigation system design. In this study, the variability of Manning\u27s roughness coefficient in time and space along the furrow under potato crops was studied. Roughness coefficient estimated along the furrow at different space and in different irrigation events were studied as regionalized variable.· The autocorrelogram did not show any clear trend. Autocorrelation coefficients were around zero for all the lags considered and within the band of significance level. The roughness coefficients estimated at an interval of 10m along the furrow were not serially correlated. The estimated roughness coefficients were normally distributed with mean and standard deviation of 0.0322 and 0.0133, respectively. Hence, roughness coefficient could be treated as stochastic parameter for hydraulic design of furrow irrigation