Field evaluation of emitter clogging in subsurface drip irrigation system

Field evaluations were conducted for the two-year subsurface drip irrigation installations in a solar-heated greenhouse for tomato to investigate the influence of lateral depth,total number of fertigation events,fertilizer applied and soil layering on emitter clogging.The results demonstrated that 2.7% of the emitters can be declared to be clogged with discharge reduced more than 25%,and 2.1% of the emitters were completely clogged.No significant influence of total number of fertigation events,fertilizer applied and soil layering on emitter clogging was observed,but a slightly greater discharge reduction was found for surface drip irrigation plots than for subsurface drip irrigation plots.No emitter clogging caused by root intrusion was detected.An investigation on the distributions of clogged emitters in the systems revealed that most clogged emitters located at the terminals of the laterals.The coefficient of variation of emitter discharge(CV) was related to discharge reduction percentage(R_q) to quantitatively evaluate the effects of emitter clogging on the uniformity of water application,showing that CV increased linearly with an increasing R_q.