Surveys have shown significant changes in carbon levels in the soil on different types of farms.
The debate over greenhouse gas emissions and emissions trading has focused on the loss of carbon dioxide and other gases into the atmosphere.
But scientists who took part in a science media centre briefing on Thursday say there needs to be more focus on the potential of soil to store carbon.
That's because soils hold at least twice as much carbon as the atmosphere does, and also store a lot more carbon than forests and other vegetation.
The scientists say increasing carbon levels in the soil can reduce emissions as well as improving soil quality and health and agricultural production.
Dairy systems on flat land lose more
Waikato University soil scientist Louis Schipper told the briefing that while carbon levels in New Zealand soils tend to be higher than world averages, they vary widely.
He says surveys done 30 years apart have shown a significant loss or increase in carbon levels associated with different pastoral land uses.
Dairy systems on flat land lost more than other systems, while hill country systems in the North Island showed a gain.
Dr Schipper says scientists are trying to determine whether the systems have reached a new steady state, or whether there are ongoing gains and losses.
