Classificació de les emocions

Land in general, and farmland in particular, is a fragile and limited non-renewable resource. Decisions on land use alternatives are complex because they require the land users and land managers to know the land capability and the necessary investments to fulfil land use objectives. This includes assessing both the land productivity under

specified management conditions and associated risks, as well as deciding the action to take to reduce risks (Rowe et al., 1981).

Understanding the bio-physical, technical and socio-economic constraints identified by a land capability assessment, becomes a major consideration in a land use planning exercise. It is generally effective to build solutions, to deal with these constraints or potential problems, into the planning phase of land use (The ACT Parliamentary Counsel, 1999).

Land (soil) capability, in the past, has been represented by soil quality, and the soil quality was evaluated on how well the soil performed all of its functions for the present and it could be conserved for future use. This cannot be determined by only measuring crop yield, water quality, or any other single variable. Soil quality cannot be measured directly, so soil scientists evaluate indicators. Indicators are measurable properties of soil or plants that provide clues about how well the soil can function (USDA, 2010b).

Indicators can be physical (soil structure, depth of soil, infiltration and bulk density; water holding capacity), chemical (pH; electrical conductivity; extractable N-P-K), and biological properties (microbial biomass C and N; potentially mineralisable N; soil respiration), processes, or characteristics of soils (De la Rosa and Sobral, 2008, p. 174) They can also be morphological or visual features of plants. Indicators can be assessed by qualitative or quantitative techniques. After measurements are collected, they can be evaluated by looking for patterns and by comparing results with measurements taken at a different time or field (USDA, 2010b, wp).

According to the Soil Quality Institute (USDA, 2010c, wp), the ultimate purpose of assessing soil quality is not to achieve high aggregate stability, biological activity, or some other soil property. The purpose is to protect and improve long-term agricultural productivity, water quality, and habitats of all organisms including people. By assessing soil quality, land users and managers can develop a sustainable management practice system (De la Rosa and Sobral, 2008).

Land capability assessment is driven by human values, goals and objectives and is mostly based on land quality (indicators). It is formed to provide information for particular purposes and needs at various scales and the assessment varies from the determination of a simple, single capability parameter to complex, multiple-capability parameters. It, also determines variations in the productivity of land with respect to the growth and management of plants. Assessment can be general or crop-specific and is a necessary step in the practical consideration of complex land characteristics (Hanson et al. 2001, p. 9).

Rowe et al. (1981) argue that land capability assessment systems can be designed to

predict productivity and the effects of the land use types, or to determine required management techniques to gain land use objectives. Land capability assessment offers an analysis of bio-physical, socio-economic, and technical characteristics of land, and therefore it provides basic information for land use planning. Land assessment explores and provides related important information such as (FAO, 1993, wp; 2007b): (1) the current management mechanism of the land, and future perspectives if present practices remain unchanged; (2) possible improvements in management practices, within the present use; (3) other feasible uses of land that can possibly be relevant to the physical and socio-economic features; (4) land uses offering possibilities of sustained production; (5) existence of adverse effects, including physical, socio- economic problems, created from each use; (6) recurrent necessary inputs to achieve the desired production and minimize the adverse effects, as well as identifying the benefits of each form of use;

In the case of a new land use where significant change is undertaken on the land itself, for examples in irrigation schemes, farming systems, or flooding control regimes, land capability assessment also reviews the following additional issues: (7) feasible and necessary changes in the condition of the land, trends of change; (8) non-recurrent necessary inputs to implement these changes.

The result of land capability assessment does not in itself determine the land use types, but provides data on the basis of which such decisions can be made through assessing

alternative potential forms of use generated for each area of land, including the consequences, beneficial and adverse.

Land capability assessment supports many different disciplines and purposes. It can be used for land use planning, exploring the potential for specific land uses and assessing the need for improved land management or land degradation control. The primary objective is the improvement and sustainable management of land for the benefit of land users. According to FAO (2007b), land evaluation, as given in the original framework (FAO, 1976) mainly refers to the identification of adverse effects and benefits of land uses.

To sum up, land or farmland capability assessment has a very significant role to play in planning and utilisation of the land resource. By this means, data related to the land including its soils, climate, vegetation, farming systems will be integrated and analysed to offer realistic alternatives for improving the use of the land. Land capability identifies vital elements, which help decision makers to avoid the costly mistakes that have resulted from investment in forms of land development unsuited to local environmental conditions.

Obviously, the determination of the capability of farmland is a tool which can be useful for agricultural land planners, land developers, and Government Authorities to assist in evaluating alternative practices or general designs that will overcome unfavourable soil or terrain characteristics and minimise off-site effects, such as sedimentation and pollution of waterways (The ACT Parliamentary Counsel, 1999). This determination is based on the analysis and integration of technical, bio-physical, policies and institutions, and socio-economic factors by the interactions and relations between these factors, as well as analysis and careful consideration of factors limiting the capability of farmland. This provides a fundamental guidance for land resource managers, land policy makers, agricultural development planners, and land users in planning, managing, and sustaining the land resource.