ghg-inventory-1990-2013

Mapping of forest areas will be iteratively improved by comparison with other spatial
forest data sets administered by the Ministry for Primary Industries. These include post-
1989 forest areas lodged with the NZ ETS, pre-1990 planted forest areas lodged with the
Forestry Allocation Scheme and new post-1989 forests planted through the Afforestation
Grants Scheme and the Permanent Forest Sink Initiative.
6.5 Cropland (CRF 4B)
6.5.1 Description
Cropland in New Zealand is separated into two subcategories: annual and perennial. In
2013, there were 371,791 hectares of annual cropland in New Zealand (table 6.5.3;
1.4 per cent of total land area) and 104,534 hectares of perennial cropland (table 6.5.3;
0.4 per cent of total land area).
Annual crops include cereals, grains, oil seeds, vegetables, root crops and forages.
Perennial crops include orchards, vineyards and their associated shelterbelts except where
these shelterbelts meet the criteria for Forest land.
The amount of carbon stored in, emitted by or removed from permanent cropland
depends on crop type, management practices, soil and climate variables. Annual crops are
harvested each year, with no long-term storage of carbon in biomass. However,
the amount of carbon stored in woody vegetation in orchards can be significant, with the
amount depending on the species, density, growth rates, and harvesting and pruning
practices.
In 2013, the net emissions from Cropland were 443.6 kt CO 2 -e, comprising 431.7 kt CO 2
from carbon stock change and 0.04 kt N 2 O (11.9 kt CO 2 -e) from the nitrogen
mineralisation on Land converted to cropland. Net emissions from Cropland have
decreased by 35.5 kt CO 2 -e (7.4 per cent) from the 1990 level when net emissions were
479.1 kt CO 2 -e (table 6.5.1).
Table 6.5.1
Cropland land-use
category
Cropland remaining
cropland
Land in conversion to
cropland
New Zealand’s land-use change by cropland category, and associated CO 2 -e emissions,
from 1990 to 2013
Net area
in 1990
(ha)
Net area
in 2013
(ha)
Change
from
1990 (%)
Net emissions
(kt CO 2 -e)
1990 2013
Change
from 1990
(%)
386,553 409,881 +6.0 356.3 339.5 –4.7
40,341 66,444 +64.7 122.8 104.1 –15.2
Total 426,894 476,325 +11.6 479.1 443.6 –7.4
Note:
1990 and 2013 areas are as at 31 December. Land in conversion to cropland includes land
that was converted prior to 1990. Net emission values are for the whole year indicated.
Values include CO 2 -e emissions from N 2 O from cultivation of land.
The Cropland remaining cropland category is responsible for the majority of Cropland
emissions. This category comprised 86.1 per cent of all Cropland area in 2013.
From 1990 to 2013, the total carbon stock stored in Cropland decreased by 3,306.9 kt C,
equivalent to emissions of 12,125.5 kt CO 2 from Cropland since 1990 (table 6.5.2). The
majority of the emissions due to carbon stock change are in the soil organic carbon pool
(3,321.4 kt C or 12,178.5 kt CO 2 ).
256 New Zealand’s Greenhouse Gas Inventory 1990–2013