Preparation and nutrient release kinetics of enriched biochar-based NPK fertilizers and agronomic effectiveness in direct seeded rice

Abstract

In present study, two enriched biochar-based fertilizers were prepared having fertilizer grade of 6-6-4 N-P2O5-K2O by intercalation of NPK fertilizers mixture solution as EB-1 and additional humic acid and seaweed extract as EB-2. In laboratory, batch experiment were done to compare nutrients (NH4+, NO3−, P and K+) release patterns of developed fertilizers along with conventional fertilizers. Enriched biochar fertilizers (EB) demonstrated much slower release pattern of NH4+, P and K+, however NO3− release was similar over conventional fertilizers. The cumulative release of N in EB fertilizers was similar to conventional fertilizer, however significantly less of P and K were released during the period of 72 hrs. The field response study of enriched fertilizers EB-2 revealed 29.5, 11.5 and 22.9% higher apparent use efficiency than conventional fertilizer. The slow nutrients release behaviour of EB fertilizers implies reduced losses and enhanced NUE as reflected by higher apparent recovery of N, P and K.

Ammoniacal and Nitrate Nitrogen Release Pattern from Biochar and Biochar Blended Urea Fertilizers in Sandy Soil

“…+ to NO 3 on reaction with the biochar matrix. A similar release pattern was reported by Gwenzi [18] and Roy [19]. Biochar addition raises the population of nitrifying organisms resulting in increased production of nitrate nitrogen thus enhancing net nitrification [17,20,21].…”