Land Evaluation for Landscape Units
Sustainable development has become a key goal of various international agencies, and the role of the land in achieving this is increasingly being recognized. More e¬cient land use is needed to, for example, feed 9 billion people in 2050, to combat climate change, and to enable sustainable biofuel production (e.g., Hartemink and McBratney, 2008). Studies have explored the potential world food supply and associated environmental quality issues, among them land degradation (Penning de Vries et al., 1995). At another scale, new farming systems are being developed to optimize fertilizer and biocide use, applying modern information technology, summarized as precision agriculture (PA; CIBA Foundation, 1997; Bouma et al., 1997a; Stoorvogel et al., 2004c). Regional planners consider alternative land use scenarios combining agricultural production with nature conservation and other functions such as water storage (Bouma et al., 2008). In all cases, land use is the core issue to be studied, while socioeconomic considerations oen play a crucial role as well. Consideration of actual and potential land use as a function of land properties ts under the broad umbrella of land evaluation as advocated by FAO (1976, 1983). Land evaluation
can be realized with descriptive, qualitative methods but increasingly includes quantitative simulation models for crop production, land use, and environmental impacts in combination with geographic information systems. All these methods need to be fed with adequate soil data, oen derived from soil surveys (e.g., Bouma, 1994). ¤is sometimes occurs mechanistically using existing databases with little attention to natural soil dynamics or landscape relationships, and this may lead to unrepresentative results. Soil survey has much to o¦er, but this expertise has to be applied and presented more e¦ectively than at present. Soil survey interpretations in soil survey reports present broad possibilities and limitations for a variety of land uses for each mapping unit. However, these represent rather narrowly dened land uses as compared with land evaluation that enables the actual assessment of land performance. Aside from the variation in space, there is also the need to consider variation in time, be it days, growing seasons, or decades. Increasingly, land evaluation is realized in close interaction with the stakeholders, ranging from farmers to planners and politicians. Innovative developments in land evaluation, emphasizing interdisciplinary approaches at di¦erent spatial and temporal scales, will be discussed in this chapter.