The inducing mechanism of emitters clogging with fertigation was explored． A laboratory
experiment was conducted to investigate the influence of three factors ( fertilizer types， fertilizer
concentration and flow path structure) on anti-clogging performance of drip emitters． The intermittent drip
irrigation experiment was studied by using two flow path types of non-pressure compensating emitters
( arc-shaped saw-tooth and cup-shaped saw-tooth) ，four levels of fertilization concentration ( 0. 5%，
1. 0%，2. 0% and 3. 0%) and four types of fertilizer ( urea，calcium superphosphate，potassium sulfate
and water soluble compound fertilizer) and the system was allowed to run for 20 h． The mathematical
analysis methods in combination with field scanning electron microscope ( FESM) ，energy dispersive
spectrometer ( EDS) and X-ray diffraction ( XＲD) technology were then used to quantitatively and
qualitatively analyze the variations of the emitter's average relative flow rate，surface topographical
characteristics and components of the clogging materials internal emitters． Ｒesults showed that fertilizer
characteristic was an important factor in deciding the emitter clogging type and degree ( P ＜ 0. 01) ，and
the influence of the two flow path structures on the accelerating effect of emitter clogging performanceneeded to consider the path structural size and style． The accelerating effect of fertilizer application on
emitter was not obvious when the concentration of fertilizer solution was less than 0. 5%． When the
concentration was increased to 0. 5% ～ 2. 0%，there were obvious changes in the quantities of outflow
discharge occurred in phosphate-fertigation，which made it clog easily，followed with urea-fertigation，the
applicability of potassium-fertigation and compound-fertigation was better than that of the former． When
the concentration was risen to 2. 0% ～ 3. 0% or higher，the clogging degree was so serious with ureafertigation，
the flow rate was decreased by 10. 26%，which was significantly higher than those of
phosphate-fertigation ( 7. 85%) ，potassium-fertigation ( 4. 07%) and compound-fertigation ( 2. 74%) ．
Fertilization can promote the clogging of the emitters． These fertilizer types had different water quality，
hence resulting into different emitter clogging risk and inducing mechanism． Emitters clogging with urea
fertigation were caused by the role of aggregation and adhesion with both crystallization of the molecular
urea state and suspended particles in the water． The adsorption function that particulate impurities to
phosphorus promoted flocculation while precipitation among solid particles was as a result of inducing
mechanism of emitter clogging with phosphate fertigation． The main inducing mechanism for emitter
clogging with potassium-fertigation was chemical precipitation because of the ion-exchange action，while
emitter clogging with compound-fertigation had the lowest risk． Therefore，fertigation with different
fertilizer types should adopt different emitter clogging controlling management strategy．
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