Authors : R. Tabatabaekoloor and M. Rezaei
Abstract: The effects of puddling intensity on shear strength, internal friction angle and cohesion were evaluated in a paddy field experiment. The treatments were Non-Puddled (NP), puddled by one pass (P1) and three passes (P3) of a rototiller. Shear parameters were measured at three soil depths in all treatments. Also, the relationships between hydraulic conductivity with internal friction angle and cohesion were developed. Results showed that the effect of puddling intensity on the shear parameters was significant (p<0.01). Puddling decreased the internal friction angle from 0.87° in NP to 0.25° and 0.21° in P1 and P3, respectively. Puddling by one pass of rototiller decreased the shear strength of soil by about 72% whereas puddling from one to three passes decreased the shear strength by 17%. The decrease in cohesion by one pass of puddler was about 73% whereas subsequent puddling to three passes decreased the cohesion by 78%. The regression equations developed to relate the soil cohesion and internal friction angle of soil with hydraulic conductivity varied linearly and had determination coefficients of 0.68 and 0.65, respectively.
R. Tabatabaekoloor and M. Rezaei, 2013. Puddling Effects on the Shear Parameters of Paddy Field Soil. Agricultural Journal, 8: 217-221.