Effect of fertilization and sediment flow hydraulic characteristics on emitter clogging in muddy water drip fertigation system†
2018
Liu, Lu | Niu, Wenquan | Wu, Zhiguang | Ayantobo, Olusola Olaitan | Guan, Yahui
In a drip fertigation system using the Yellow River, suspended solids in the water serve as a bridge between physical flocculation and chemical adsorption. They impact the emitter clogging process and flow turbulence properties. Therefore, a laboratory test was conducted with artificial muddy water drip fertigation (MWF) to investigate the anti‐clogging performance of emitters. Four types of fertilizer (i.e. [CO (NH₂)₂], Ca (H₂PO₄)₂·H₂O, K₂SO₄ and [CO (NH₂)₂] + KH₂PO₄ + KNO₃) were applied at 0.5, 1, 2 and 3% concentrations respectively. The results showed that the relative discharge of emitters (Dra) remained in a fluctuation balance phase, and at 0.5% concentration with MWF, there was a decrease of 5, 11.1, 8.8 and 4.9%. For fertigation concentrations between 1 and 2%, the fluctuation balance phase significantly reduced, and the Dra began a linear decrease of 12.5, 42.2, 37.6 and 5.1%. At a fertilizer concentration increase of 3%, the Dra improved relatively with urea and P fertilizer drip irrigation but slightly declined with K and compound fertilizer. The particle size distribution of flocs ranked from broad to narrow as follows: P fertilizer > K fertilizer > urea > compound fertilizer. Urea showed a viscosity‐reducing effect on muddy water (MW). Conversely, K fertilizer exhibited the greatest viscosity‐increasing effect, followed by P fertilizer, while compound fertilizer exhibited the least viscosity‐increasing effect. The filter criteria of the drip irrigation system can be suitably reduced for drip fertigation with urea in the Yellow River irrigation area. © 2018 John Wiley & Sons, Ltd.
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