1. A survey of bean crops was carried out in the Oxford area in the years 1947–9 with the object of studying farmers' methods, and the factors affecting establishment and development of the crop in the field.

2. The season and the fertility status of the soil have a profound influence on the development of the crop, while plant density affects the growth of the individual plant.

3. Hard winters cause crop losses which may amount to more than 50% of the plants. Mortality continues throughout the season.

4. A warm dry spring and an equable summer temperature favour pod production more than hot, dry seasons.

5. High plant densities cause: (1) a reduced rate of pod formation on each plant over a wide range of conditions, but a greater reduction on poor land than under good conditions; (2) a reduction in stem formation on low fertility fields (but not on high fertility land); (3) a significant increase in pod production per acre on high quality fields.

6. A high level of fertility leads to significantly more pods/acre, owing to better plant survival and increased branching and podding.

7. Under conditions favouring vegetative growth, there appears to be some competition between stem production and pod production, for the correlation between stems/plant and pods/plant found on low fertility land and in dry seasons no longer holds under good growing conditions.

8. In an average crop, there is a very serious loss of flowers and partly matured pods, which may amount to 85% of the flowers formed.

9. This wastage may be due to (1) unsatisfactory pollination or self-infertility, (2) inadequate availability of certain plant nutrients, (3) unsuitable environmental conditions, particularly low light intensity in dense crops.

10. Botrytis cinerea can cause a high wastage of crop, but it did not figure prominently during the 3 years of the survey, and appeared to be associated with deficiency of potash and/or phosphate in the only two severe outbreaks that occurred.