Burford, J.R., Dowdell, R.J. and Crees, R.1981: Emission of nitrous oxide to the atmosphere from direct drilled and ploughed clay soils. Journal of the Science of Food and Agriculture32, 219-23.
2.
Cannell, R.Q.1981: Potentials and problems of simplified cultivation and conservation tillage. Outlook on Agriculture10(8), 379-84.
3.
Cannell, R.Q., Davies, D.B., Mackney, D. and Pidgeon, J.D.1978: The suitability of soils for sequential direct drilling of combined harvested crops in Britain: a provisional classification . Outlook on Agriculture9(6), 306-16.
4.
Cannell, R.Q., Ellis, F.B., Christian, D.G., Graham, J.P. and Douglas, J.T.1980: The growth and yield of winter cereals after direct drilling, shallow cultivation and ploughing on non-calcareous clay soils. Journal of AgriculturalScience, Cambridge94, 345-59.
5.
Douglas, J.T., Goss, M.J. and Hill, D.1980: Measurement of pore characteristics in a clay soil under ploughing and direct drilling, including use of radioactive (144Ce) technique . Soil and Tillage Research1, 11-18.
6.
Douglas, J.T. and Goss, M.J.1982: Stability and organic matter content of surface soil aggregates under different methods of cultivation and in grassland. Soil and Tillage Research2, 155—75.
7.
Ellis, F.B. and Barnes, B.T.1980: Growth and development of root systems of winter grown cereals after different tillage methods including direct drilling. Plant and Soil55, 283-95.
8.
Ellis, F.B., Christian, D.G. and Cannell, R.Q.1982: Direct drilling, shallow tine cultivation and ploughing on a silt loam silt 1974-80. Soil and Tillage Research2, 115-30.
9.
Ellis, F.B., Elliott, J.G., Pollard, F., Cannell, R.Q. and Barnes, B.T.1979: Comparison of direct drilling, reduced cultivation and ploughing on the growth of cereals. 2 Winter wheat and spring barley on a calcareous clay. Journal of AgriculturalScience, Cambridge33, 391-401.
10.
Ellis, F.B. and Howse, K.R.1980: Effects of cultivation on the distribution of nutrients in the soil and the uptake of nitrogen and phosphorus by spring barley and winter wheat on three soil types. Soil and Tillage Research1, 35-46.
11.
Gourman, M.A., Coutts, J. and Riley, D.1978: Changes in soil structure and physical properties associated with continuous direct drilling. Transactions 11th International Congress of Soil Science, Edmonton, 1290.
12.
Hodgson, D.R., Proud, J.R. and Browne, S.1977: Cultivation systems for spring barley with special reference to direct drilling. Journal of AgriculturalScience , Cambridge88, 631-44.
13.
Larson, W.E.1981: Soil tillage research in the US. Soil and Tillage Research1, 319-22.
14.
Ministry of Agriculture, Fisheries and Food1970: Modern farming and the soil. London : HMSO.
15.
Phillips, M.C.1978: Survey of the use of minimum cultivations in Warwickshire. ADASQuarterly Review (Spring), 13-19.
16.
Pidgeon, J.D.1981: A preliminary study of minimum tillage systems (including broadcasting) for spring barley in Scotland. Soil and Tillage Research1, 139-51.
17.
Pidgeon, J.D. and Soane, B.D.1977: Effects of tillage and direct drilling on soil properties during the growing season in a long term barley monoculture system. Journal of AgriculturalScience, Cambridge88, 431-42.
18.
Pollard, F., Elliott, J.G., Ellis, F.B. and Barnes, B.T.1981: Comparison of direct drilling, reduced cultivation and ploughing on the growth of cereals. 4 Spring barley and winter wheat on silt loam soils over chalk. Journal of AgriculturalScience , Cambridge97, 677-84.
19.
Russell, E.W.1971: Soil structure: its maintenance and improvement . Journal of Soil Science22(2), 137-51.
20.
Soane, B.D., Dickson, J.W. and Campbell, D.J.1982: Compaction by agricultural vehicles: a review. III Incidence and control of compaction in crop production. Soil and Tillage Research2, 3-36.