02 Contents Frame
POTENTIAL FOR AGRICULTURAL BIOMASS PRODUCTION
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40 2019 ND-CP 413905
- Điều hướng trang này:
- Plant growth modelling
- Plant water requirements
| POTENTIAL FOR AGRICULTURAL BIOMASS PRODUCTION
Agro-ecological zoning The Agro-Ecological Zones (AEZ) approach is an example of indicator modelling. It is a GIS-based modelling framework that combines land evaluation methods with socio-economic and multiple-criteria analysis to evaluate spatial and dynamic aspects of agriculture within a broader environmental context (FAO 1996). The methodology involves the representation of land in layers of spatial information and combination of these layers using a Geographic Information System. The combination of layers produces agro-ecological cells with georeferenced land resources information. The results of an AEZ assessment are estimated by grid cell and aggregated to national, regional or global scale. The results include identification of areas with specific climate, soil, and topographic constraints to crop production; estimation of the location, extent and productivity of rainfed and irrigated cultivable land and their potential for expansion; quantification of cultivation potential of land currently in forest ecosystems; and impacts of climate change on food production potential, geographical shifts of cultivable land, and implications for food security (Fischer et al., 2002). Such national- level information with global coverage is critical for knowledge-based decision making for sustainable agricultural development. Plant growth modelling Plant growth modelling is process-based and typically involves the calculation of three components: plant water requirements, biomass production and plant litter decomposition. Plant growth models are essentially point-oriented and may be linked with a GIS through multiple model runs for a representative range of points across the grid surface. Plant water requirements The major driver for a plant water balance is the reference evapotranspiration. Five major steps can be identified in a water balance: 1. calculation of the reference evapotranspiration, 2. determination of the plant growth characteristics and plant parameters, 3. calculation of the actual evapotranspiration, 4. calculation of plant-available water capacity and 5. calculation of the water balance. Annex 3 – Tools for land evaluation 93 Allen et al., (1998) present an updated procedure for calculating reference and actual evapotranspiration from meteorological data and crop coefficients. In addition to the method of using a single coefficient to calculate the actual evapotranspiration (Doorenbos and Pruitt 1977), Allen et al., (1998) recommend the use of two factors to separately describe evaporation and transpiration. A further revision and update provides details on the Penman-Monteith combination method as a new standard for reference evapotranspiration and advises on procedures for calculating the various parameters and estimating missing climatic data. tải về 0.57 Mb. Chia sẻ với bạn bè của bạn:
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