REVIEW REPORT FOR NEW ZEALAND

61. The supporting information in the NIR contains some gaps, for example it is explained that the OVERSEER model is used to calculate the nitrogen excretion from animals.  However, no data on nitrogen (N) content in feed is reported in the NIR, making it difficult to review the total excreted nitrogen by animals (N_ex) without additional information from the Party.  The AD for dairy cattle provided in the NIR and the CRF tables is consistent with data reported by Statistics New Zealand as dairy cattle.  According to the IPCC good practice guidance dairy cattle refers to “cows that have calved at least once and are being kept to produce milk”.  According to Statistics New Zealand dairy cattle is “the number of dairy cows and heifers in milk or calf estimated at 4.1 million.” This means that the calculated CH₄ IEF from enteric fermentation and N_ex cannot easily be compared with other Parties.

62. New Zealand uses enhanced livestock characterization in its calculations, which is in accordance with the IPCC good practice guidance for key categories, although the NIR explains that only a detailed level of livestock characterisation is used.  The AD reported in the NIR are reported at detailed level.  The ERT recommends that New Zealand in its next NIR include a description of the enhanced livestock characterization used in calculations, basic AD and other data relevant for understanding the methods used, and improve the transparency of the NIR.

63. Recalculations have been reported for the whole time series because of the change in use from tier 1 to tier 2 for CH₄ emissions from manure management and a changed leaching factor (Frac_LEACH).  The overall effect of these recalculations is an increase for 1990 of 0.9 per cent and for 2003 a decrease 0.6 per cent.  For all years the AD used are an average of three years, which is in accordance with the IPCC good practice guidance.