Author: Varinder Singh
Company: RM plc

1.	To manage grassland efficiently so that the maximum amount of beef is produced, it is important to understand how nitrogen is cycled. The diagram shows some steps in the flow of nitrogen. The figures in brackets show the approximate amount of nitrogen passing through that part of the cycle in kilograms per hectare per year.

(a)	(i)	Name a compound that could be classified as organic nitrogen.
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(1)
 
(ii)	The annual flow of nitrogen through organic nitrogen could not have come from dung alone. Suggest another source of organic nitrogen.
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(1)

(b)	(i)	Name one of the types of bacteria involved in the process labelled A
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(1)
 
(ii)	Name the type of bacteria involved in the process labelled B
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(1)
 
(c)	From the figures given in the diagram, calculate the annual flow of nitrogen through ‘grass’
Show your working.

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(2)
 
(d)	Explain the advantage to cattle farmers of encouraging the growth of clover in grassland.
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(2)
(Total 8 marks)