Could the addition of hydro-retention polyacrylamide gels into a substrate really increase its available water amount?

The aim of the paper is to clarify the advantages for the hard ornamental nursery stocks and to environment derived by the addition of two commercial hydrophilic polyacrylamide gels in a peat/pumice (1:1 V/V) substrate. In both cases, the water absorption capacity of the two hydrophilic polyacrylamide gels was proportional reduced with the presence of dissolved salts in the water. It was found that in the tested substrate an addition of 2 g/L of super-water-retention can increase the amount of retained water of about 130 g for each litre of substrate. However, only 40-50% of the greater amount of water retained by super–water retention was available for the crop. Under operating conditions (drip irrigation with relatively saline water) the increase of water available for the crop in the range (0- -10 KPa) is only about 30 g for each gram of polymer added to the substrate. This higher substrate available water could increase the resistance of the plants to the absence of irrigation for 1-2 days. In conclusion, the addition of hydrophilic polyacrylamide gels to the substrate seems to have positive effects on plants, especially after the end of cultivation (selection and preparation of plants, packaging, storage, transport) and, probably, also during the early stages after transplanting in the customer’s garden, where optimal irrigation could be not always guaranteed.