Guan Yahui, Niu Wenquan, Liu Lu, Li Xuekai, Zhang Wenqian. Effect of fertilizer type and concentration on sediment transport capacity of dripper in drip fertigation with muddy water[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(1): 78-84. DOI: 10.11975/j.issn.1002-6819.2018.01.011
    Citation: Guan Yahui, Niu Wenquan, Liu Lu, Li Xuekai, Zhang Wenqian. Effect of fertilizer type and concentration on sediment transport capacity of dripper in drip fertigation with muddy water[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2018, 34(1): 78-84. DOI: 10.11975/j.issn.1002-6819.2018.01.011

    Effect of fertilizer type and concentration on sediment transport capacity of dripper in drip fertigation with muddy water

    • Abstract: Emitter clogging has been an important factor restricting the application of drip irrigation system. In order to improve the anti-clogging ability of the dripper, the front part of the drip irrigation system needs to be equipped with multi-stage filtration equipment or facilities. This study investigated the effect of different fertilizers on the sediment transport capacity during the integrated irrigation of muddy water with fertilizer in order to make rational allocation of filtration equipment and facilities of the first drip irrigation system, to reduce the cost of filtration facilities and to improve the efficiency of drip irrigation system. A total of 3 kinds of fertilizers (urea, potassium sulfate and water-soluble compound fertilizer) as well as 3 different concentrations (1%, 2% and 3%) were chosen to carry out intermittent irrigation clogging test in muddy water with the sediment concentration of 1 g/L. The accumulated sediment, discharge sediment of drippers and rate of discharge sediment for drippers were analyzed. Tap water was applied as the test water. Experimental sediment was taken from river flood beach silts along Weihe River in Shaanxi Yangling. The working pressure of this test was set to 70 kPa based on the preliminary experiment results. In order to increase irrigation times of this experiment, the test stopped when the average relative flow rate was below 70%. The test also stopped after 20 times of irrigation even though the relative flow rate was still above 70%. The results showed that the application of muddy water could enhance the sediment transport capacity of dripper. Different types and concentrations of fertilizer had different effects on the sediment transport capacity of dripper. Sediment transport capacity of dripper increased with rising urea concentrations. Compared with no fertilization treatment, when the urea concentration was 3%, the capacity value increased by 11% (P<0.05). Sediment transport capacity of dripper decreased with the rising concentrations of potassium sulfate and compound fertilizer. As the concentration of potassium sulfate was 1%, the sediment transport capacity of dripper was significantly higher than that without fertilization(P<0.05) but as the concentration of compound fertilizer was above 2%, sediment transport capacity of dripper was lower than no fertilizer treatment. The slope of the fitted straight line between the standardized accumulated sediment and the standardized accumulated irrigation amount could be used as the evaluation index for sediment transport capacity of dripper. The smaller the slope indicated that as the irrigation volume increased, the output of sediment of the dripper was lower, and the sediment transport capacity of dripper was also lower. The dripper was more likely to be clogged. Discharge sediment for drippers increased with the increasing frequency of irrigation. At the later stage of irrigation, its growth slowed down. Fertilization increased the maximum value of discharge sediment for drippers. With the increase of irrigation times, the rate of discharge sediment for drippers gradually decreased. After applying urea, rate of discharge sediment for drippers decreased with increasing irrigation times. After applying urea in the muddy water, the viscosity coefficient of irrigation water decreased with the increase of fertilizer concentration, while it increased with the rising concentration of compound fertilizer. After applying potassium sulfate in muddy water, the coefficient of irrigation water viscosity was higher than that without fertilization. The fertilizer concentration was an important factor that affected drip sediment output capacity. Appropriate fertilization concentration should be determined according to different types of fertilizers. The results provide valuable information for determining the anti-clogging strategy of dripper and improving the sediment transport capacity of dripper to guide integrated drip irrigation of water and fertilizer with high sediment concentration in the Yellow River irrigated area.
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