<h4>Options to further enhance production efficiency</h4>
<p>New Zealand already operates a highly efficient and productive pastoral system. Over the past 20 years, farmers have steadily improved feed and nutrition, animal genetics, pasture management, and animal health. These provide permanent, cumulative gains: globally, for instance, genetic improvement is estimated to account for an average 0.5-1% efficiency increase per animal per year. The best way to keep reducing New Zealand&rsquo;s greenhouse gas intensity is for farmers to continue to increase the production efficiency of their operations as much as possible, and as fast as possible.</p>
<p><strong><a href="industry.html">Read more</a></strong></p>
<p>By continuing to push production efficiencies, farmers could further reduce emissions intensity and constrain the expected growth in agricultural greenhouse gas emissions as overall animal production continues to increase.</p>
<h4><strong>Options to reduce growth in absolute emissions</strong></h4>
<p>Most of the additional currently available options to reduce the growth in absolute emissions are related to the dairy sector, which employs a greater diversity of management strategies and feed inputs than the almost entirely grazing-based sheep and beef sectors. The economic efficiency of those options will vary greatly between farms and farm systems and has not been assessed yet for New Zealand as a whole.</p>
<p>USE MORE LOW-NITROGEN FEED</p>
<p>New Zealand pasture-based diets provide more nitrogen to animals than necessary for their optimal growth and productivity. Livestock<br />excrete this surplus nitrogen in their dung and urine, where it contributes to nitrate leaching and nitrous oxide emissions.<br />Dairy production in New Zealand is increasingly making use of supplementary feed to improve animal performance and balance<br />year-to-year and seasonal variations in grass growth. Many of the supplementary feeds contain less nitrogen than normal pastures and<br />thus could help reduce nitrous oxide emissions on farms. Feeds include domestically-grown supplementary feed, commonly maize silage, hay<br />and silage, and imported supplements, such as palm kernel expeller (PKE). Whether increased use of supplementary feeds is viable depends<br />on international milk prices and domestic environmental regulations. If feeds are imported from overseas, care also needs to be taken<br />to avoid &lsquo;pollution swapping&rsquo; &ndash; where New Zealand could achieve emissions reductions and higher production by driving up emissions<br />offshore &ndash; and to keep an eye on any biosecurity issues.</p>
<p>REDUCE NITROGEN FERTILISER USE</p>
<p>Another option is to use less nitrogen fertiliser per hectare or per animal. This requires careful management of nutrient flows, for<br />example by using more purchased feed and/or growing forages with a higher yield per hectare, and optimising the use of animal manures.<br />Fertiliser use per animal increased throughout the 1990s and peaked around 2004, but has declined since while productivity per animal has<br />continued to increase. There is reason to believe this can be pushed further without compromising production, although it may increase<br />risk to farmers and require higher farm management skills. Reducing overall nitrogen fertiliser use would also help improve water quality.</p>
<p>MANAGE MANURE FROM HOUSED ANIMALS</p>
<p>Dairy production in New Zealand is intensifying; temporary housing is becoming more common to avoid pasture damage in wet weather, or to<br />control nitrate leaching to waterways. Confinement of animals means that a greater proportion of dung and urine can be captured and treated<br />before being spread back onto land. Farmers can avoid spreading manure when soils are wet and nitrous oxide emissions and nitrate<br />leaching losses are high.</p>
<p>But there are two key challenges:</p>
<ul>
<li>more research is needed to determine the potential nitrous oxide reduction from spreading manure at different times, compared to<br />urine and dung being deposited directly</li>
<li>storing manure generates methane from anaerobic ponds which may offset any reductions in nitrous oxide emissions. To make manure<br />storage a mitigation option, the methane has to be captured and either flared or used to generate biogas. This can be costly; options<br />and economic viability depend on the volume of manure treated.</li>
</ul>
<p>The optimal balance between grazing and housing, and tools for minimizing emissions from housed animals, will continue to evolve over<br />the coming years and will also reflect other environmental goals such as reducing nitrate leaching.</p>
<p>MAINTAINING CARBON INPUTS TO SOILS</p>
<p>It has been difficult to demonstrate practices for New Zealand soils that reliably increase soil carbon, as the effectiveness of any management practice is highly dependent on climate and existing soil carbon stocks and management history.</p>
<p>Globally, one of the most robust good practices is to avoid overgrazing to ensure constant grass cover and production to continue carbon inputs<br />to soil and to reduce erosion risk. Farmers can also reduce the risk of soil carbon losses by avoiding too intense disturbance of the plant/soil<br />system such as frequent cultivation.</p>
<p>Overall in New Zealand, there is no consistent trend in soil carbon stocks in flat land. There is some evidence of increasing soil carbon<br />stocks in hill country, but the reasons for this are not clear yet (it could simply reflect a slow recovery of top soils following the initial clearing of<br />forests, or it could reflect improved management practices).&nbsp;<strong><a href="soil-carbon.html">Read more&nbsp;</a></strong></p>