DMI based Biogenic emissions estimator   
   
               
  Biogenic methane emissions from ruminants are a function of their digestive systems and relate directly to Dry Matter intake ("DMI").  The factor for NZ grass fed sheep and cattle is 21 (approx) and 21.6 grams respectively per kg of DMI.  For the manure derived emissions, (nitrous oxide in the case of dairying and methane), there are formulae. Soil emissions can be calculated on the basis of a MfE factor per head on-farm at 30 June each year. In other words, on-farm biogenic emissions can all be calculated from Dry Matter consumed (DMI) and knowing the mix of sheep and cattle.

Analysis
In the case of individual farming enterprises, if FARMAX or some other reporting tool is being used, the per hectare Kg of dry matter consumed, ie DMI, over the reporting years is one of the outputs. Alternatively, if working with a consultant, that figure should have been estimated.

In the absence of those, a user can "have a play" using DMI/ha scenarios and from that the emissions implications can be calculated. In this App, it provides a basis for estimating the area of forest plantings required to (theoretically) mitigate a user-defined quantity of emissions. (Note: There is currently no agreed mitigation option for methane.)

The most accurate way of calculating DMI is by calculating the theoretical feed requirements of a given enterprise's annual livestock configuration. NZAgri.com has a Beta version almost ready for testing, based on weight and growth feed requirements published by Beef and Lamb NZ. 		 
  Instructions
In the case of any commercial farming operation (in the absence of reporting by, for example FARMAX) an enterprise's consumed dry matter per hectare will have been discussed in some context.  That figure, along with the effective hectares and stocking mix (ie sheep and cattle as Stock Units) are the only figures required to calculate a reasonable estimation of the biogenic emissions (methane and nitrous oxide). 

Further refinement can be achieved in relations to fertiliser applications.  If all fertiliser purchases are from the same supplier, they will have a summary of N, dolomite and lime.  For N, use the "Non-DAP N" option, enter the figure provided and enter 100% in the "Define/Redefine" cell.

Finally, there is an area where the user can consider mitigation scenarios, calculating the area of forestry required to achieve defined mitigation outcomes.

 		 
  In order to be able to save your data, you can create a unique login URL by tapping on the button below. When the page reloads, Bookmark the URL (or save Home Screen on a mobile devise). The App will then be accessible from any devise with a browser.  
               
 
 
                 
  Analysis      
   Assumptions  Methane - GWP100   - GWP20    
    Nitrous oxide          
    MjME/KgDM          
  CH4 / kgDMI (gms) Sheep          
      Cattle        
  Effective land area 100    ha (can't be defined in this version)  
  Effective land area          
  If you know your Dry Matter consumption per hectare pa, enter it below.  
  Annual consumed KgDM / ha        
Grass / ha (kgDM pa)
  Utilisation (%)          
 
  kgDM      
  Feed quality (MjME/kgDM)          
  Quality adjusted KgDM per hectare    kgDM (Consumed)    
                 
  Stocking configuration  Stock units* 30-Jun          
    Ewes          
    Other sheep        
    Cows          
    Other cattle        
  * Enter 0 if no stock in class      
Enteric methane emissions
     kgCH4 / ha      
    CO2e      kgCO2e / ha      
  Manure methane (CH4  kg/ha pa) Based on digestibility (DMD)    
    CH4 CO2e            
  Sheep            
  Cattle            
                 
  Soil emissions (N2O)              
    Number CO2e factor Kg pa          
  Sheep          
  Cattle          
          kg CO2e /ha pa  
  Summary CO2e       
    Kg /ha            
   Enteric CH4            
   Manure CH4            
   Soil N2O            
               
   
       
   Fertiliser analysis  
    Note: There are default N percentages for Urea, DAP and SOA. The N % is required for any non-Urea nitrogn fertilisers.  
    Fertiliser
 Gross Percent-  Define /   CO2e  
    tonnes age Redefine Factor  
   
 
   
 
   
 
   
 
   
 
   
 
   
 
               
  Emissions summary  (Based on 100 ha)   Tick to use
 
      Mitigate N2O CH4 CO2 Mg CO2e  
    Fertiliser
 
    Animals
 
         
   
Year  %  
     /tonne  
Price can't be changed in Demo App
    Mitigation forestry*  
     
   
   
Growth period  years  
      Variation with Tables
Experience has shown that the growth of Exotics has exceeded the Lookup Tables by up to 50% while regenerating natives are less than the Tables.
   
    User-defined sequestration        
    Change above Cover Mg CO2e Mitigate Forest ha  
    N2O    
    CH4
 
    CO2    
     
       
       
    * There is currently no ability to mitigate methane.    
  Note: In the mitigation space, the MfE calculator gives credit for regenerating natives. There is no legislative support for that but it should be the case, albeit at 3.4 tonne pa.