Effect of Fertilizer Loaded Nanoclay/Superabsorbent Polymer Composites on Nitrogen and Phosphorus Release in Soil

A leaching study was conducted to evaluate effectiveness of fertilizer loaded nanoclay/superabsorbent polymer composites (NCPCs) as a slow release carrier of nutrients. Three types of NCPCs (I, II and III) synthesized from Kaolinite, Illite and Smectite dominated nanoclays, respectively were loaded separately with di-ammonium phosphate (DAP) and urea solution. Release of P and total mineral N from NCPCs loaded with DAP and urea, respectively, were compared with corresponding conventional fertilizer (CF). Release of P and N were studied independently with a factorial CRD experiment under four types of fertilizer (NCPC-I, NCPC-II, NCPC-III and CF) in combination with three types of soils (Alfisol, Inceptisol and Vertisol). Cumulative P and total mineral N recovery significantly increased under NCPC-I (+57.3 and +16.2 %, respectively), NCPC-II (+55.2 and +15.4 %, respectively) and NCPC-III (+88.3 and +27.3 %, respectively) over CF. Reduced nutrient losses (P fixation and N volatilization) under NCPC treated soils owing to their slow release property resulted in higher recovery. Moreover, NCPC doped with smectite type of clay (NCPC-III) endowed with better slow release property than NCPC-I and NCPC-II. © 2014, The National Academy of Sciences, India.