To changes in water supply in a changing climate

5.1 Introduction a changing climate and its effects on plant growth and functioning As rainfall patterns become more unpredictable as climate changes, plants will be subjected to increasing fluctuations in soil moisture availability. These fluctuations are likely to have substantial impacts on plants in natural communities and on crop plants in agriculture (Davies & Gowing, 1999). For example, Silvertown etal. (1999) have shown how sensitive plant community composition can be to small...

References

A Breshears, D.D. (1998) Drought-induced shift of a forest-woodland ecotone rapid landscape response to climate variation. Proc. Natl. Acad. Sci. USA, 95, 14839-14842. Araus, J.L. (2004) The problems of sustainable water use in the Mediterranean and research requirements for agriculture. Ann. Appl. Biol., 144, 259-272. Austin, A.T., Yahdjian, L., Stark, J.M., Belnap, J., Porporato, A., Norton, U., Ravetta, D.A. A Schaeffer, S.M. (2004) Water pulses and biogeochemical cycles in arid...

David Viner James IL Morison and Craig Wallace

The geographic distribution of plant species, vegetation types and agricultural cropping patterns demonstrate the very strong control that climate has on plant growth. Solar radiation, temperature and precipitation values and seasonal patterns are key determinants of plant growth through a variety of direct and indirect mechanisms. Other climatic characteristics are also major influences, such as wind speed and storm frequency. There is a rapidly growing number of well-documented instances of...

Net primary productivity

Net primary productivity (NPP) may be quantified as a linear function of the pho-tosynthetically active radiation absorbed by the canopy (APAR) where e the radiation conversion efficiency into biomass. The value of APAR depends on incident short-wave solar radiation, leaf area index (LAI) and the canopy structure, which affects the light extinction coefficient (k). The slope of the relationship between plant productivity and APAR, i.e. e, varies with plant type and environmental conditions...

Wateruse efficiency

The quantification of the dependence of plant productivity on water resources may be viewed as the slope of the relationship of net primary production and the amount of water actually lost by transpiration (T) over the year as NPP WUEt x water supply x proportion of water used by plants, where the season-long water-use efficiency (WUEt) or transpiration efficiency is the ratio of biomass produced to the corresponding plant transpiration in g (dry matter) kg-1 H2O or mmol C mol-1 H2O (Jones,...

Agriculture

The world cultivated land is 80 dedicated to rainfed agriculture, with the remaining 20 allocated to irrigation (Rockstrom, 2003). Nevertheless, irrigated agriculture is a major consumer of water resources and 40 of the food and agriculture commodities are produced in irrigated areas. With the predicted growth in human population and climate change scenarios of increasing water scarcity, especially in the interior of continents and semi-arid regions, achieving a better efficiency of use of...