Roots may promote infiltration and thus reduce runoff and soil erosion; they may also serve as pathways for water to move to the groundwater, facilitating groundwater recharge. By increasing our knowledge of these processes we hope to make recommendations for the better management of vegetation in arid lands of the Mediterranean. (http://www.silsoe.cranfield.ac.uk/iwe/medalus.htm)
In the semi-arid grassland on the Arid Lands Ecology Reserve on the Hanford Site in south-central Washington State, three legume flushes occurred in the past decade.Estimates of leguminous nitrogen in both native and disturbed vegetation after a flush showed that nitrogen in the legume (above-ground) doubled the amount of nitrogen associated with vascular plant tissues.( http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=6444278)
Wednesday, May 23, 2007
The environmental impact of Nitrogen fixing trees
The usage of Nitrogen fixing trees will change the environment. The addition of moist, shade, mulch and nitrogen will create zones of different properties.
“We found a higher number of shrubs under canopies, whereas that of grasses and perennial forbs increased in intercanopy areas. Concentrations of organic matter, nitrogen, potassium and phosphorus, factors limiting biological productivity in Monte desert soils, were significantly higher under than outside P. flexuosa canopies. Electrical conductivity and concentrations of Na+, Ca++, Mg++ were higher in the northern than in the southern microhabitats. …… We conclude that P. flexuosa modifies the spatial pattern of plant species in the shrub and herbaceous layers and the chemical conditions of the soil, generating spatial heterogeneity on different scales.”
(Journal of Vegetation Science Article: pp. 543–550 Effects of Prosopis flexuosa on soil properties and the spatial pattern of understorey species in arid Argentina RossiBertilde E.A, VillagraPablo E
If we translate the scientific gibberish to ordinary English the article simply states that Nitrogen fixing trees create a biological diversity that was not there before. They also enrich the soil in areas of scarcity.
“We found a higher number of shrubs under canopies, whereas that of grasses and perennial forbs increased in intercanopy areas. Concentrations of organic matter, nitrogen, potassium and phosphorus, factors limiting biological productivity in Monte desert soils, were significantly higher under than outside P. flexuosa canopies. Electrical conductivity and concentrations of Na+, Ca++, Mg++ were higher in the northern than in the southern microhabitats. …… We conclude that P. flexuosa modifies the spatial pattern of plant species in the shrub and herbaceous layers and the chemical conditions of the soil, generating spatial heterogeneity on different scales.”
(Journal of Vegetation Science Article: pp. 543–550 Effects of Prosopis flexuosa on soil properties and the spatial pattern of understorey species in arid Argentina RossiBertilde E.A, VillagraPablo E
If we translate the scientific gibberish to ordinary English the article simply states that Nitrogen fixing trees create a biological diversity that was not there before. They also enrich the soil in areas of scarcity.
Trees and climate change
Forests could be used to combat climate changeIn addition to preventing forests from being turned into other land-uses, new forest-based carbon stores should be created through afforestation (new plantings) and reforestation (replanting of deforested areas), FAO says.Carbon stocks in forest biomass reach the highest values per hectare in Western and Central Africa and Central and South America, according to FRA 2005.Particularly in the tropics, where vegetation grows rapidly and therefore pulls carbon from the atmosphere more quickly, planting trees can remove large amounts of CO2 from the air within a relatively short time. There, forests can fix as much as 15 tonnes of carbon in their biomass and wood per hectare per year.FAO and other experts have estimated that global carbon retention resulting from reduced deforestation, increased forest regrowth and more agroforestry and plantations could make up for about 15 percent of carbon emissions from fossil fuels over the next 50 years. http://www.fao.org/newsroom/en/news/2005/1000176/index.html
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