Improving crop production by the use of PAM: Potential benefits to Australian agriclture.

An anionic polyacrylamide (PAM) at the rate of 7 kg ha-1 applied to the surface of a degraded hard-setting soil increased the germination of cotton seeds by 84%. Significant improvement in soil physical properties was also observed in treated soils. A cross-linked PAM at the rate of 0.03 and 0.07% increased the amount of water retained by a sandy soil by 23 and 95%, respectively. Consequently the water use efficiency of soybean plants grown in PAM treated soils was increased by 12 and 19 times, respectively. Increasing amounts of PAM in sandy soil enabled to extend the irrigation interval without any adverse effect on the grain yield of soybeans. An anionic PAM at the rate of 10 kg ha-1 reduced the turbidity of water in a sodic soil by 83%. However, PAM combined with small amounts of gypsum was highly effective in reducing the turbidity of water without significant effect on the percolation rate of water through the soil.