Table 6.

Crop yields, where 100% of the RB209 (Anon, 2010) recommended amount of fertiliser is applied, prices and energies.

Crop	Grain yielda (t ha−1)	Reference	Energyb (GJ t−1)	Reference	Grain pricec (£ t−1)	Straw yielda (t ha−1)	Reference	Energyb (GJ t−1)	Reference	Straw priced (£ t−1)
Winter wheat 1st	8.3	HGCA data, Lang and Allin (2006), FBS data (2004–2008), Nix (2008), Anon (2011d)	8.82e	Elsayed et al. (2003)	172.36	3.5	Nix (2008)	7.44	Elsayed et al. (2003)	43
Spring barley	5.4	Lang and Allin (2006), FBS data (2004–2006), Anon (2011d)	8.82	Assumed to be the same as for winter wheat	164.42	3	Anon (2011d)	7.44	Assumed to be the same as for winter wheat	59
Winter barley	7.0	HGCA data, Lang and Allin (2006), FBS data (2004–2006), Nix (2008), Anon (2011d)	8.82	Assumed to be the same as for winter wheat	164.42	3.6	Nix (2008), Anon (2011d)	7.44	Assumed to be the same as for winter wheat	59
Winter field beans	4.0	Nix (2008), Anon (2011d)	16.42	Moerschner and Lücke (2002)	206.67	0.0		0		0
Winter oilseed rape	3.3	FBS data (2004–2008), Nix (2008), Anon (2011d)	23.95e	Elsayed et al. (2003)	374.08	0		0		0

^aCrop yield values are averages taken from various literature sources, shown to two significant figures.

^bThe energies of the grain and straw are shown for each crop shown to two decimal places.

^cThe prices of the grain yields are taken from Anon (2011b) averaged from November 2010 to October 2011. The barley grain price is fixed to be £7.94 t⁻¹ less than the wheat grain price as this is the calculated difference between these two prices over the time period noted.

^dThe prices of the straw are taken from Anon (2011b) and from Defra (Anon, 2011e). The barley straw price is fixed to be £16 t⁻¹ more than the wheat straw price as this is the calculated difference between these two prices over the time period noted.

^eEnergy value for the conversion of the wheat grain into bioethanol and for the conversion of oilseed rape into biodiesel.