A G Gillingham and K R Betteridge

Land and Environment Management Group, AgResearch Grasslands, Palmerston North

New targets for increased productivity from the dairy, and sheep and beef industries are 4% and 5% respectively annually, at a time of ever heightening environmental awareness. If these targets are to be achieved, a combination of both increased average pastoral production, and or utilisation, as well as increased average production per animal, are required. While a major part of this increase will occur by increasing the productivity of the presently lower-than-average farms, leading farmers will also have to examine means of further increasing efficiency or productivity for them to remain viable.

One prospect is to examine the natural variability in pastoral productivity within farms, whether these are dairy or hill country properties, and to more accurately provide the inputs necessary for optimum production and economic returns. Land Management Units (LMU) are blocks, individual paddocks or even smaller units of land which have similar characteristics that are consistently different through seasons or years. The size of each LMU is defined by the scale at which a particular differential management strategy can practically be applied, and the associated economic and/or environmental rewards realised. This scale may be different for contrasting management inputs eg grazing cf fertiliser application. The greatest advantage from adopting such an approach will usually be found where input, or production, differences between contrasting LMUs are large, or where significant improvements in environmental conditions can be achieved.

New Zealand's pastoral production systems may offer greater opportunity for development and application of differential management strategies than exists in many cropping systems overseas. On dairy farms, although a significant range in productivity exists from paddock to paddock, and also within paddocks, generally, all are treated with the same fertiliser product and application rate, the same grazing practice and duration, and other management inputs. With the size of dairy farms generally increasing, the range in soil and production variability within each property will invariably increase.

Hill country farms have marked and permanent soil and topographic variability, associated with slope and aspect differences, which can result in more variable pasture production than on dairy farms. Yet again, a uniform rate of fertiliser is usually applied to large areas of such land.

The development of strategies and technology to better match land use with land capability, offers an opportunity both for increased production and more accurate protection of waterways, and non- productive areas.

Examples of the potential application of new technology for more precise management strategies within contrasting pastoral systems are examined, and the advantages and limitations to these approaches are discussed.

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