MOBILIZATION OF NUTRIENTS FROM SLOW-RELEASE FERTILIZER AS INFLUENCED BY HYDROGEL AND WATER-QUALITY

The combined effect of low quality water (0,500, 1000, 1500 and 2000 ppm salts; each in three ratios 10:0, 7.5:2.5 and 0:10 for NaCl: Na2SO4 salts) and hydrogel material (Evergreen 500) on the mobilization of nutrients from slow-release fertilizer (Plantosan 4D) and their absorption by barley seedlings were studied. The results indicate that the Na content in the barley shoots was proportional to its concentration in the media. Increasing the Na content in the plant tissues as a result of increasing either total salt concentrations or NaCl to Na2SO4 ratios depressed the absorption of most of the macro and micronutrients, with the exception of nitrogen, by intact seedlings. As a result of the chemical form of the polymer, mixing the hydrogel with deionized water released an excess amount of nitrogen and sodium in the outer solution. The accumulation of most of the cations in the plant tissues decreased with the adding of the gel material to the saline solutions.