COMBINED ACTION OF HYDROGEL AND CONTROLLED-RELEASE FERTILIZERS ON GROWTH OF TOMATO PLANTS

Polymeric Hydrogels were prepared with the capacity to absorb quantities of water multiple times their weight. A technique of trapping the water-soluble fertilizers of the trade, with the ability to convert them into Controlled-Release Fertilizers (CRF), has also been developed. In this research a comparative testing of these materials and of their equivalent commercial water-soluble fertilizers was held out. A tomato growth experiment in closed pots was carried out for this purpose. Two different types of fertilizers were used, that is the CRFs we prepared and their equivalent water-solubles of the trade, in two different doses (N,P,K). The fertilizations were combined with dry mass polymeric hydrogel mixed with the soil in two levels, 0% and 0.2%. During the experiment that lasted for 14 weeks, there were four samplings of leaves to determine the levels of the N,P,K. At the end of the experiment, the plant yield was measured on a dry mass basis. The findings showed that the addition of the polymer to the soil does not significantly affect the plants yield. However, the combination of the polymer and the CRF notably increased their yield from 17.5% to 27.9%. As to the absorption of nutrients from the plants, the absorption of N appeared more regular, while K and P did not present any important differences.