Effects of superabsorbent polyacrylamides on efficiency of water use by crop seedlings

Abstract

K e y words: Cross-linked polyacrylamide, evapotranspiration ratio, water use efficiency, water storage, crop establishment.Cross-linked polyacrylamide expands upon contact with water to form a pliable gel that in a growing medium constitutes a reservoir of moisture available for uptake by plants. Trials with seedlings of three crop species (Lactuca sativa L , Raphanus sativus L , Triticum aestivum L) using measurements of yield and evapotranspiration ratio show that gel-stored moisture is utilised with a greater ef3ciency than conventional forms of water. Moreover, gel storage of water provides a buffer against temporary drought stress and the potential for reducing the risk of failure of certain crops at establishment.The development of new techniques and materials for enhancing the efficiency of use of water supplies where they are scarce or where irrigation costs are high is a priority for the survival of rural communities in arid and semi-arid regions. Measures that permit improved use of water resources, and better survival and growth of agricultural and forestry crops, must be able to assist in buffering the periodic failure of seasonal rainfall, and be both economic and practical.Among recent initiatives to achieve better use of water supplies is the introduction of synthetic, cross-linked polymer additives for growing media. Polyacrylamide, polyvinylalcohol and starchacrylate co-polymer superabsorbents have the capacity to absorb substantial quantities of water and subsequently release this moisture from the gel matrix that forms upon contact between the original crystalline polymer and free water. Formulations in the polyacrylamide category can absorb up to 500 times their own weight of distilled water (Johnson 1984a), though this performance is notably reduced in the presence of soluble salts (Johnson 1984b).Addition of superabsorbent gel to growing media has been shown to increase water holding capacity by up to 400% (Johnson 1984a) and to decrease water stress 43 1 J Sci Food Agric 0022-5142/90/$03.50

Effects of Hydrophilic Polymer on the Survival of Buttonwood Seedlings Grown Under Drought Stress

“…They found also that, HG media allowed for several weeks to pass before seedlings started to die whereas in the control with no HG plants started to die after some days of drought. In Downloaded by [Cornell University Library] at 13:45 17 November 2014 sandy soils, it was found that incorporation of HGs for Lycopersicon esculentum (Henderson and Hensley, 1986), Lactuca sativa, Rhaphanus sativa, and Triticum aestivum (Johnson and Leah, 1990) increased both the dry weight and the time from irrigation stop to wilting.…”

Application of Superabsorbent Polymers for Improving the Ecological Chemistry of Degraded or Polluted Lands

“…www.clean-journal.com Amorpha, poplar, and Eleagnus [50], barley, wheat, and chick pea [51], Eucalyptus [52], pine [53,54] Acacia melanoxylon [55], lettuce and barley [56], Platycladis orientalis and Pinus tabulaeformis [57], Chlorophytum comosum [58], lettuce, rape and wheat [59], pea [60], tomato [61], tomato and lettuce [62], soy bean [63] and ten tree species in Southern China [64]. The influence of SAPs on the water metabolism of plants can be seen in the following experiment.…”

Metal-binding particles alleviate lead and zinc toxicity during seed germination of metallophyte grass Astrebla lappacea

“…Several substrate ameliorants have been trialled to precipitate or increase metal sorption in soils and therefore decrease the metal concentration in soil solution including lime [12], organic matter [13], vermiculite [14] and zeolite [15]. Hydrogels have been used to ameliorate plant growth in arid conditions [16][17][18][19][20] and saline or metal-contaminated soils [21][22][23] by providing a temporary source of water during germination and seedling establishment and diluting soil ion concentrations to tolerable levels [24].…”