Studies with Water Absorbing Polymers: II Nitrogen Retention Capacity and Effects on Phaseolus Bean Development, Growth and Yield

  • O.T. Edje
  • J.M. Hlatshwayo


Agrogel is a water absorbing polymer that swells and forms gelatinous mass with water. The mass can retain water and nutrients and release it slowly over time. These characteristics have stimulated interest in their use, especially for greenhouse crop production, where watering is frequent resulting in leaching of soil nutrients. The experiment reported below was designed to investigate the effects of polymer on nitrogen retention and on yield of Phaseolus beans. The greenhouse experiment consisted of two polymer levels (no polymer and 1.5g polymer per kg of sand), two nitrogen sources (urea and limestone ammonium nitrate) and three levels of each {0. 30 and 60 kg/ha N}. The medium was river sand and bean seeds were sown in pots. Results showed that treatments with polymer retained 33.3% significantly [P<0.01] more nitrogen compared to the control and nitrogen retention in urea form was 10% higher compared to that from limestone ammonium nitrate. The highest seed yield, of 1862 kg/ha, was obtained with the treatment combination containing polymer with 30kg ha N from the urea source.

UNISWA Research Journal of Agriculture, Science and Technology Vol 3 (1) 1999: pp 56-61

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eISSN: 1029-9645