Erosion control in furrow irrigation using Polyacrylamide.

The aim of this study was to evaluate the effect of different application forms of polyacrylamide (PAM) on the detachment and transport of soil particles in a simulated irrigation furrow. PAM application rate in all cases was 20 kg ha(-1) and tested on 6-m-long furrows at 3% slope. In order to generate increasing hydraulic shear stresses, five inflow rates (75, 100, 150, 200, and 250 liters per hour) were applied consecutively. All treatments were evaluated in three replicates. The soil used for the experiments was a Pelic Vertisol representative of the region. Flow and geometty parameters, as well as soil detachment rates were evaluated. Results indicated that application of PAM significantly decreased rill erosion by 81% for granular application, 84% for liquid PAM injected in the inflow and 93% for PAM sprayed on the soil surface, as compared to the control treatment. Critical shear stress gradually increased from 0.65 Pa for the control to 1.0, 1. 1, and 1.4 Pa for granular, liquid injected and liquid sprayed PAM, respectively. In consequence, the rill erosion factor, K, decreased from 0.004 m(-1)s in the non-treated furrow, to a 002 m(-1)s, 0.001 m(-1)s and 0.0007 m(-1)s for granular, liquid injected and liquid sprayed PAM, respectively. PAM can be used in any form to control soil erosion in furrow irrigation systems.