The Growth, N Uptake, N Use Efficiency by Corn due to Application of SRF-Urea

Nitrogen (N) is one of essential elements for plant, needed in the largest number, and often supplied through urea. However, the efficiency of N-uptake by plant from Urea was about 30-50% due to N loss as nitrate (NO3-) and N gas (e.g. NH3 and N2O). This problem could be more severe in light soil with low SOM and CEC. This study was to investigate how slow-release fertilizer (SRF) urea could mitigate these issues. The SRF urea was produced from Urea at 100% and 80% of the recommended rate, coated by biochar either rice husk (Rh) or corn cob (Cc) biochar, pyrolyzed at 450 oC in a muffle furnace for one hour and sieved for 0,5 mm diameter. Two control treatments, without and with urea at the recommended rate, and both treatments were not coated by biochar, were established. All treatments were applied to corn plants grown on sandy soil in greenhouse pots. The plant was harvested at 42 days after planting (DAP). The result showed that compared to Control without urea, Urea application, with and without biochar in average increased corn biomass in average 51.6% and N uptake about 154%. The SRF of P2 and P5 tended to have highest plant biomass. Increased nutrient use efficiency by treating both Cc and Rh biochar-coated urea at 80% of the recommended rate, which tended to result in the highest efficiency. Biochar-coated urea could be the alternative SRF-urea to increase plant growth and N uptake efficiency from urea in sandy soil.