Download - New Zealand Society of Soil Science

anticipate. He was persuaded to undertake the work by officials who clearly pointed out that no-one
else was better qualified than he because of his understanding of the soil and landscape properties that
lay at the heart of the “East Coast problem”.
Norman Taylor's talk and the subsequent discussions unconsciously, but neatly, foreshadowed the
misgivings that many soil scientists have had, about their dealings with central and local government,
commercial and legal parties and communities. The context we work in has been fundamentally
changed however and many current concerns exist in the border areas between agricultural production
and environmental protection because soils are used by people and are changed because of that use.
Concepts like equilibrium states begin to lose relevance as human activity influences the soil forming
factors and more or less continuous change occurs. Many soil scientists have responded to the
changed context pragmatically, as Norman Taylor did, but often remain deeply uncomfortable about
moving outside strict discipline boundaries. Much of the tension around these issues arises from the
different standards of evidence that are acceptable to different groups. Scientists have attitudes toward
objectivity and uncertainty that are often inconvenient in the wider world.
Soils are changed by human use. Some of the changes can be predicted and measured. Some can be
managed or mitigated in an informed way. Others changes are poorly understood and the potential for
unknown effects always exists in the complex ecological setting that soil provides. As conflicts over
the use of soil and water grow so does the volume of data, information, opinion and propaganda from
interest groups that the soil science community needs to assimilate, contribute to, criticise or debunk.
Three examples of the interaction between soils and human activity are now discussed:
1. Cultivation history can be an important agent in determining the distribution of soil processes
across landscapes. Nitrification is one of these processes and can exert subtle but powerful change in
soil properties. In some areas at least it will be in farmers' interest to understand the status of
nitrification in their soils
2. Two perceptions of the soil resource and the importance of knowing the history of resources in
a consideration of their future.
3. The question “Is there money in the (soil) bank?” is used to consider the value of the soil
resource to the New Zealand economy,
1. Cultivation as an agent of change
Over the past decade the movement of nitrogen (N) from grassland farms to surface or subsurface
water has become a matter of public policy interest. Methods for managing or mitigating this have
been widely pursued in publicly and commercially funded research programmes. Public policy has
also begun to focus on planning to reduce current loadings of N in catchments or to limit future growth
of those N loads. Farmers have a new interest in determining whether or not the properties of their
soils and landscapes are being accurately represented (or at least not over-assessed) in, or by, the
models used to predict N loss from their farms. Equity becomes an important issue in all of these
deliberations and this produces some important changes for the soil science community.
The assumptions made in the nutrient budgets or process models that are used to define N losses from
farms become very important in this context. Nitrification is assumed to be an active process in
almost all cases and this profoundly affects the estimates of N loss from farms. This view tends to
neglect the influence of cultivation, but the history of agriculture is essentially a history of cultivation
of soils. Cultivation is the means to establish a crop and also the means to enhance nutrient supply to
it. Cultivation turns the combined nutrients in the soil organic matter, a natural capital stock, into a
liquid asset. The tyranny of topography has meant that the agricultural exploitation of the New
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