Can Acidified Biochar Lower the Nitrogenous Gas (N2O and NH3) Emissions from Cattle Manure?.

Cattle feedlot manure loses 75-80% of N, mainly in the form of nitrous oxide (N₂O) and ammonia (NH₃). Mitigating these emissions is a global environmental concern.  Biochar is a widely used soil conditioner, having a potential to adsorb NH₃ and lower the N₂O gas emissions in manure. Yet, due to inherent basic nature of biochar, direct application of biochar as a manure amendment is controversial, since NH₃ volatilization is generally higher under basic conditions. Use of acidified biochar, might lower the effects of high NH₃ volatilization, by bringing down the pH, along with lower N₂O emissions. To explore above potential benefits of acidified biocar, laboratory incubation experiments was conducted for 30 day period in 24 chambers (0.22 x 0.14 x 0.12 m) at 20±1 ^oC. Air dried cattle manure, sieved to get < 2mm particles, was filled into chambers and treated with acidified biochar; pH 6 (using acetic acid) at 30 t/ha rate. ¹⁵N labelled synthetic urine was applied into the chambers, at a rate of 0.43 l/m². Experiment was arranged in a RCBD design with 4 replicates. NH₃ from chambers were trapped in a 0.5 M H₂SO₄ solution and manure medium was analysed routinely for NH₄⁺ and urea retention, organic C and N, ¹⁵N, moisture content and pH. Gas sampling was done weekly for analysing N₂O, N₂ and CH₄.