Keywords

Canadian Agricultural Nitrogen Budget (CANB) v4.0 model; Residual Soil Nitrogen; Nitrogen leaching lost; Scenario analysis; Soil Landscapes of Canada

Location

Session B2: Advances in Agricultural Modelling

Start Date

11-7-2016 4:50 PM

End Date

11-7-2016 5:10 PM

Description

A Canadian Agricultural Nitrogen Budget (CANB) model has been developed since 2002 to estimate Residual Soil Nitrogen (RSN) and N leaching loss across Canadian farmland. The current results showed that national RSN averages in Canadian farmland (annual N input minus annual N output) increased from 9.4 kg N ha-1 in 1981 to 23.6 kg N ha-1 in 2011 as mainly affected by the increase in synthetic fertilizer N usage and biological N2 fixation. With annual drainage, about 50 and 80% of residual soil N was lost in Central (Ontario and Quebec) and Atlantic Canada, respectively, through leaching and varying according to soil and climate conditions. The objective of this paper was to present nitrogen leaching scenario analysis using the CANBv4-scenario model. Agricultural regions (6 to 11) in each province were integrated with the CANBv4-scenario model to assess how RSN and N leaching losses change in response to nitrogen input scenarios in the studied agricultural region, province and ecoregion. Four scenarios were generated each with four levels: (1) reducing synthesized fertilizer N by 10 to 40%; (2) reducing manure N by 10 to 40%, (3) reducing N2 fixation by 10 to 40% which was done by decreasing alfalfa land area by 10 to 40% while increasing improved pasture by that same land area and (4) combining scenarios 1, 2 and 3. The results showed that both residual soil N and N leaching loss decreased significantly with the reducing levels of synthetic fertilizer N, manure N, and N2 fixation. Scenario 4 showed combined results of soil N leaching loss efficiently. For instance, soil N leaching loss could be reduced by 42% under a 20% reduction level in the three N sources in 2011 farmland practice. More results at provincial and regional scales were presented.

 
Jul 11th, 4:50 PM Jul 11th, 5:10 PM

Residual Soil Nitrogen Scenario Analysis of Canadian Farmland using a Canadian Agricultural Nitrogen Budget (CANB v4.0) Model

Session B2: Advances in Agricultural Modelling

A Canadian Agricultural Nitrogen Budget (CANB) model has been developed since 2002 to estimate Residual Soil Nitrogen (RSN) and N leaching loss across Canadian farmland. The current results showed that national RSN averages in Canadian farmland (annual N input minus annual N output) increased from 9.4 kg N ha-1 in 1981 to 23.6 kg N ha-1 in 2011 as mainly affected by the increase in synthetic fertilizer N usage and biological N2 fixation. With annual drainage, about 50 and 80% of residual soil N was lost in Central (Ontario and Quebec) and Atlantic Canada, respectively, through leaching and varying according to soil and climate conditions. The objective of this paper was to present nitrogen leaching scenario analysis using the CANBv4-scenario model. Agricultural regions (6 to 11) in each province were integrated with the CANBv4-scenario model to assess how RSN and N leaching losses change in response to nitrogen input scenarios in the studied agricultural region, province and ecoregion. Four scenarios were generated each with four levels: (1) reducing synthesized fertilizer N by 10 to 40%; (2) reducing manure N by 10 to 40%, (3) reducing N2 fixation by 10 to 40% which was done by decreasing alfalfa land area by 10 to 40% while increasing improved pasture by that same land area and (4) combining scenarios 1, 2 and 3. The results showed that both residual soil N and N leaching loss decreased significantly with the reducing levels of synthetic fertilizer N, manure N, and N2 fixation. Scenario 4 showed combined results of soil N leaching loss efficiently. For instance, soil N leaching loss could be reduced by 42% under a 20% reduction level in the three N sources in 2011 farmland practice. More results at provincial and regional scales were presented.