Efficacy of a Hydrophilic Polymer Declines with Time in Greenhouse Experiments

Abstract

<jats:p>The effect of a hydrophilic polymer (Broadleaf P4®; HP) on growth of cucumber seedlings (<jats:italic>Cucumis sativus</jats:italic> L.) was investigated. Furthermore, the efficiency of HP to absorb water over a period of time was studied. Predetermined amounts of HP (0.0%, 0.1%, 0.2%, 0.3%, and 0.4% dry-weight basis) were mixed with moderately calcareous sandy loam soil in pots. At the end of the first experiment (42 days), the growth of the seedlings was recorded, as well as the maximum soil water-holding capacity (WHC). The same pots were left for a drying period ranging from 2 to 5 months and then used for another four successive experiments. Soil WHC increased significantly with increasing level of HP, but decreased after each experiment. After five experiments, the WHC had decreased 17.3% and 27.8% where HP was added at the rate of 0.1% and 0.4%, respectively. The bulk density of soils decreased significantly with addition of HP and had increased after five growing experiments at each HP rate. Cucumber seedling growth was stimulated by addition of the polymer. The greatest vegetative growth, expressed as leaf area and shoot fresh and dry weights, was observed at 0.3% HP in the first and second experiment, but at 0.4% in the third and fourth.</jats:p>

Water retention properties of a sandy soil with superabsorbent polymers as affected by aging and water quality

“…This confirms results of Al‐Harbi et al. (1999) who found a decrease in water holding capacity of 17.3% and 27.8% at added rates of 0.1% and 0.4% polymer due to aging, respectively. Similarly, Geesing and Schmidhalter (2004) found that the beneficial effect of polymer addition was partly lost and water holding capacity in a sandy loam decreased by about one third within 77 d. However, the process responsible for our finding that the aging effect appears stronger in the soils with higher concentration of SAP addition is so far unclear.…”

“…However, it is not clear whether this change in comparison to the free polymer's behavior ( Bhardwaj et al, 2007) relates equally to water retention in middle pores (with plant‐available water) and fine pores (with water that is not plant‐available). Secondly, there is evidence that the improvement of the effective hydraulic properties is not stable with time, but underlies some degradation ( Al‐Harbi et al, 1999; Jobin et al, 2004; Geesing and Schmidhalter , 2004). Nevertheless, field investigations that quantify this degradation are rare.…”

Synthesis and evaluation of trimethylolpropane triacrylate crosslinked superabsorbent polymers for conserving water and fertilizers

“…These factors may affect the economic value of crops grown on fields amended with SAP. In addition SAPs are quite fragile and tend to break apart easily during repeated swelling and deswelling under soil, which may bring down their water retention capacity 58…”

Novel superabsorbent cellulose‐based hydrogels crosslinked with citric acid

“…[1][2][3][4][5][6][7][8] Recently, their application has been extended also in agriculture, since could represent a suitable solution for water storage and controlled release. [9][10][11][12][13] The swelling capacity of hydrogels has been studied by different authors. It is well known that the presence of fixed charges, typical of polyelectrolyte gels, determines a significant swelling of the polymer in water.…”