Abstract:
Polyacrylamide (PAM) has been widely used to improve soil water holding capacity and control infiltration rate
of the soils. However, limited studies have been conducted on the interactions between soil water holding
capacity and PAM rates in different soil textures. This study targeted to analyze the relations between soil
texture and water holding capacity as a response of increasing PAM applications rate. PAM rates of 0.03, 0.1,
0.13, 0.16, 0.23, 0.33 and 0.67% by weight were applied to clay loam, clay and sandy loam soils. Water holding
capacity (q) at field capacity (q 0.01 MPa for sandy loam and q0.033MPa for clay loam and clay) and wilting point
(q1.50 MPa) were measured with a pressure plate apparatus. The values of water holding capacity were regressed
as a function of PAM rate, and the slope and intercepts of regression lines for clay loam, clay and sandy loam
soils were compared to decide the homogeneity of these functions. Increasing PAM rate significantly increased
the water holding capacity in all three soils (P<0.05). The regression lines obtained for sandy loam, clay loam,
and clay were all significantly different from one to another, revealing that soil texture has a significant effect on
the function of PAM in promoting water holding capacity in these soils. Therefore, we concluded that soil
texture should be considered in optimizing the results from PAM applications.
