CAN BIOCHAR FULFILL THE NITROGEN NEED OF MAIZE UNDER REDUCED NITROGEN INPUT?

Nitrogen (N) is very important to support the yields of maize, however, the yields remain a relative stable level along the increasing input of N fertilizer.This brings a waste of resources and environmental risks.Biochar (BC), a carbon-rich products, had a positive effect on the growth of maize.So, we want to detect that whether BC can satisfy the N need of maize under reduced N input.The field trials were conducted, which located in Heilongjiang Province, northeast of China.Taking the farmer's N fertilizer application rate (112 kgꞏhm -2 , N1) as control, the N fertilizer amount was reduced by 30% (78.4 kgꞏhm -2 , N2), with two levels of BC addition (B1 and B2) based on N2.The soil total nitrogen (TN), ammonium N (NH4 + -N) and nitrate N (NO3 --N) content of N2B1 are at the same level as the TN, NH4 + -N and NO3 --N of the farmers' N application (N1) at the jointing stage (P>0.05).We found that the yield of maize in N2B1 increased by 4.33 % compared to that in N1.And BC increase significantly field N use efficiency (N accumulation, N fertilizer use efficiency, N fertilizer agronomic efficiency and N fertilizer partial productivity).The results showed that the application of BC can meet the needs of maize under reduced N conditions and increase the yield of maize.There will be the optimum dosage for BC application.