1. Anonymous, 1986. The analysis of agricultural materials. Reference Book 427. MAFF, London.
2. Anonymous, 1994. Fertiliser Recommendations for Agricultural and Horticultural crops. Reference Book 209. MAFF, London.
3. Bailey, R.J. & S.J. Groves, 1992. The effect of irrigation on the yield and nitrogen fertiliser response of potatoes.Aspects of Applied Biology 33:45–50.
4. Chambers, B.J. & S.J. Richardson, 1993. Relying on soil mineral nitrogen reserves.Journal of the Science of Food and Agriculture 63: 128–129.
5. Clutterbuck, B.J. & K. Simpson, 1978. The interactions of water and fertiliser nitrogen in effects on growth pattern and yield of potatoes.Journal of Agricultural Science 91: 161–172.