The Nitrogen Cycle - GCSE

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in industrial processes. •They contain nitrates & other mineral nutrients They are produced as granules, powder or liquid. and are spread by tractor. wheat wheat burley ~Crop Rotation ~ Crop rotation means growing different crops in a field in different years. Examples are shown in this table. Year 1 Year 2 maize barley. potatoes Year 3 beans fallow green manure •Beans belong to a group of plants called legumes. Other. legumes include peas, soybean & clover •Fallow means • leaving the field with no crop for a year.. • Green Manure means growing a non-crop legume: as clover, then ploughing it into the soil. such ✔ Biology. in The Nitrogen Cycle N Nitrogen is used in living things in the form of DNA & Protiens The Nitrogen Cycle Denitrifying bacteria Lightning Nitrogen-fixing bacteria in soil Nitrogen in air Proteins in plants Nitrates in soil Feeding Nitrifying bacteria Death • New crops have less nitrates so yield falls. Restoring Soil Fertility. S Pro's • Easy to use •Known amount of nutrients added to crop. Proteins in animals •Dissolves easily in soil water .Con's • Run-off can cause eutrophication of waterways Urea Decay bacteria & fungi Ammonia in soil Fixation Nitrogen Nitrogen fixation is a process by which nitrogen from the atmosphere is converted to a more complex form that plants can uptake and use. This is carried out by: ~ Free living bacteria (natural) ~ Bacteria in root nodules (natural) ~ Industrial fixation to make fertiliser. (artificial). Root Nodules Nitrogen in Agriculture ~ Artificial Fertilisers • At harvesting, the crop is cleared from the field. • The plants are taken away so nitrogen from the soil is lost. • The nitrate concentration of the soil falls. several methods of adding nitrates to the soil, 7 N 14.007 including: artificial fertilisers ~Natural Fertilisers * natural fertilisers (eg. manure) Natural Fertilisers are nitrogen-rich because they come from; animals (e.g. manure) and plants (compost). ★ Crop rotation including legume crops or a year of fallow land. •Decomposing bacteria break down protiens & other Natural vs Artificial Fertilisers Artificial fertilisers Natural Fertilisers Pro's • Useful way of clearing. animal waste.. • Cheaper than artificial fertiliser Con's • Must be spread before the new Crop is planted. • Possibly unknown quantity of nutrients. Artificial Fertilsers: • Artificial fertilisers are made in industrial processes. •They contain nitrates & other mineral nutrients They are produced as granules, powder or liquid. and are spread by tractor. wheat wheat burley ~Crop Rotation ~ Croprotation means growing different crops in a field in different years. Examples are shown in this table. Year 1 Year 2 maize barley. potatoes Year 3 beans fallow green manure •Beans belong to a group of plants called legumes. Other. legumes include peas, soybean & clover •Fallow means • leaving the field with no crop for a year.. •Green Manure means growing a non-crop legume: as clover, then ploughing it into the soil. such