Flashcards
Untitled
Cards in this deck (24)
- 1MacronutrientsNeeded in quantities - nitrogen + phosphate
- 2micronutrientsneeded by plants in plants in small quantities - zinc + copper
- 3The three nutrient application methodsNatural fertilisers, artificial fertilisers, cultural methods
- 4Advantages Natural fertiliserse,g, manure + compost
Often cheap waste products that help maintain soil structure, reduces soil erosion and provide food for soil biota. - 5Disadvantages natural fertilisersBulky + difficult to apply + may not contain required nutrients
- 6Advantages artificial fertiliserse.g. ammonion nitarate
Have controlled composition and convenient to apply - 7disadvantages artificial fertilisersDo not add organic matter or maintain soil biota
Energy expensive to manufacture and are more likely to causes water problems - 8Cultural methods Green manureCrop grown and then ploughed back into the soil to conserve nutrients and structure rather than to produce food. Legumes such as beans have root nodules with symbiotic nitrogen-fixing bacteria
- 9Hydroponics - case studyInvolves the growth of croips in a nutrient solution rather than a solid growth medium. Usually carried out in a greenhouse. Productivity is maximised by controlled limiting factors.
- 10Hydroponics advantagesNo weeds
No soil to hold pathogens
nutrient supply is optimum so is not limiting factor - 11Hydroponics disadvantagesHigh inputs of nutrients + energy
High level of technical/knowledge needed - 12TopographyTerraces can be cut to create small flat fields on a slope
- 13Reliefcant be controlled
- 14Soil salinity What happens when there is excessive salt in soil waterWhy can osmotic dehydration of the roots cause plants to die
- 15The first method that increases soil salinationIrrigating with groundwater that has high salt content
- 16A second method that increases soil salinationLarge volumes oif water percolating dwon into the soil due to excessive/poorly lined irrigation channels can cause the water table to rise close to the surface, bringing dissolved salts with it.
- 17The salt concentration of the soil increasesas the salt are left in the soil when water evaporates from the soil
- 18When can extra low-salt water be usedto wash the salts out of the soil but this greatly increases water consumption + can cause ecological problems by increasing the salinity of the local river that receives the salt.
- 19What can be added to the soil to increase salt solubilityGypsum
- 20What can incorrect PH doCan kill detrivores/decomposers since it will be outside of their range of tolerance
- 21What do many positively charged ions doAdsorb onto negatively charged clay particles in the soil.
- 22Why do plant roots use ion-exchangeTo mobilise the soil nutrients
- 23Ion exchange involvesPlants releasing Hydrogen ions from their root hairs. The hydrogen ions then displace nutrients ions from clay particles. The freed ions can then be absorbed by roots
- 24What happens if the soil is too acidicThe nutrients will have already been leached away before the plant can perform ion exchange
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- Flashcards on Untitled, created by Louisa Wilcox on 03/04/2021.
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- Louisa Wilcox
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