Beans are legumes (family Leguminosae), a crop that is able to make use of atmospheric nitrogen to enrich the protein content of both the plant and seed. Legumes do this by utilising bacteria that inhabit nodules in the roots that "fix" the nitrogen. When the roots decay, the nitrogen in the root becomes available to the following crop as a fertiliser - an important source for both conventional and organic systems. Legumes (typically beans and peas) which are grown for their seed are known as pulses.

Beans are an important economic crop grown mainly for their seed which is rich in protein. The bean plant is characterised by a strongly developed tap root that reaches deep into the soil. This adds organic matter to the subsoil as well improving its structure. Beans grown in the UK are known as field beans and are completely distinct from Navy beans - the source of baked beans. Navy beans do not successfully grow in the UK.

The bean crop is classifed into two main groups; winter and spring. Winter crops which are sown in the late autumn are higher yielding but of slightly inferior quality. By comparison with spring crops which are usually sown in January, winter beans are exposed to greater disease risks whereas spring beans are more likely to suffer from summer drought.

The emerging bean crop; note the irregular distribution of the plants. Many farmers choose not to precision drill the crops but to simply broadcast the beans with a fertiliser spreader and then plough the bean under. Beans contain a significant nutrient resource in the seed and so germination will still safely occur even if the seed has been ploughed deep under the soil.

For husbandary reasons beans are rarely grown more often than one year in six in a crop rotation. This usually precedes winter wheat which responds favourably to the higher soil nitrogen status following the bean crop. Beans are also effective as a break crop by allowing the control of problem weeds to other crops. Image illustrating spring beans in June.

The flowers of the bean crop - note the square stem of the plant. Beans are a cheap crop to grow with relatively low inputs of fertiliser and pesticide required.

The mature pods prior to harvest. Modern varieties of the crop stand erect with most of the pods high up the stem where they can be easily harvested. Typically beans contain twice the protein content of cereal crops like wheat - a factor that has contributed to their continued use in the UK over the last 3000 years.

The national bean crop typically covers between 110 and 170,000 hectares each year. Average yields for the UK crop are around 3.75 tonnes per hectare with typical values between £70 - £90 per tonne.

Most of the bean crop is grown for stock feed and is used as a locally grown GM free alternative to protein crops like soya. The major human consumption market for beans is the Middle East where beans are used prior to the Ramadan fasting period.

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