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Establishment

Cultivation method

Which establishment method is best ?

There are several ways of establishing winter bean crops.

 

Ploughing in – This is the traditional method, sometimes beans go in relatively late in the autumn when soil conditions are often less than ideal and soil moisture levels are high. Ploughing in is often the only option with high soil moisture, however it is not the ideal particularly as beans normally follow winter wheat in the rotation, chopped straw ploughed down with the beans is the cause of many problems, forming an anaerobic layer in the soil. The alternative of baling the straw all too often causes soil compaction. Dependent on soil moisture content and soil type, ploughing may be coupled with furrow pressing which will provide a more level surface for spraying and harvesting. Post drilling cultivation can be used to level seedbeds, providing soil structure damage is not caused. Crops however can be established by running the beans over the ground and then following on with the plough, they will withstand depths of 15-20cm on heavy soil and up to 26cm deep on the lighter free draining soil types. It is important to level the seed bed though as it can cause difficulties at harvest if left unworked.

 

Drilling – This is a more precise method and optimum establishment is achieved by deep drilling, following good ploughing. Some cereal drills are not capable of achieving the optimum of 5 inches (12.5cm) and . It is important to place the seed at the optimum depth and above any layer of straw. However it is a less weatherproof system than the plough. There is the risk that rain following ploughing, may make the soil too wet to drill.

 

Min-till – This is another method, which has become more popular in recent years. Single pass machines offer opportunity to sow beans at good depths enabling a different weed control regime using cheaper widespread herbicides. It is important that the coulters used cover the seed over as it is not desirable to leave open slits leaving the bean seed exposed to the elements.

 

Min-till and direct drilling systems are the most suitable for beans and the majority of UK farmers establish bean crops this way. Preference varies from farm to farm, but optimum establishment is achieved by deep drilling, with seed being covered by a minimum of 3cm of soil, but can be sown as deep as 15-20cm when ploughed in.

 

The late autumn drilling date of winter beans means that soil conditions are often less than ideal. Where soil moisture is too high for drilling and/or the soil structure is poor, winter beans can be ploughed in instead of drilling, allowing any soil structure damage to be rectified in the process. Beans are sensitive to surface soil compaction and deep loosening of the soil profile has been shown to increase yields. However,

seed distribution and subsequent seedling emergence can be uneven when ploughed in, thus the density of crops may not attain the plant density for optimum yields.

 

Drilling Date

The aim is to get well-established plants at the 1-2 node stage, or two pairs of leaves, before the winter sets in. While this is normally achieved by sowing mid-October to early November, there is flexibility with sowing date. Modern winter bean varieties can still be sown throughout December and January and into February.

Rotation

Like all large seeded legumes, winter beans should not be grown more than once every five years on the same land. If they are grown closer than this, there must not be more than two bean crops in a seven year period, which should then be followed by a minimum four year break. This avoids potential issues with soil borne nematodes, which can build up populations when host crops are grown closely together.

 

Soil Type

Winter beans are traditionally grown on moisture retentive, heavier soils which are less suitable for spring sowing. Winter beans are generally more resilient to soil conditions than other crop legumes, and grow well on a range of soil types, from loamy sands to deep silty clay loams.

Beans benefit from good drainage so action should be taken to minimise compaction and water logging in bean crops. Beans do not require a fine seedbed and can tolerate cloddy conditions, although these may impact on weed control.

 

Blackgrass Control

Growers are increasingly advised to sow many crop types later to reduce blackgrass populations. The relatively later sowing window for winter beans enables good cultural control of blackgrass. With the optimum sowing time for winter beans being mid October to early November, this gives ample opportunity for one or two cultural control options.

Growth

Field beans are an indeterminate crop, thus producing flowers, pods and seed over a period of time throughout crop development whilst vegetative growth is continuing. This may be a benefit to a crop that is sensitive to drought so that later formed pods may compensate for poor growth of earlier produced pods. Temperature is the main determinant of crop development and determines the duration of each developmental phase. However, high temperatures may be linked with drought conditions, which shorten developmental periods and may reduce yield.

 

The response of field beans to soil moisture may explain why soil conditions are an important determinant of yield. Research at Nottingham University during the 1980’s showed that crops established in compacted soils develop small, shallow root systems that exploit a smaller volume of soil and take up less water than those grown in a well structured soil. Yields were reduced by up to 15% in experiments over a number of seasons. Winter beans are suited to soils with good water holding capacity and generally yield better in heavy clays than on light, drought prone land.

Implications of plant population on crop husbandry

High plant populations may not decrease yield but they may reduce profitability through increased constraints and increased need for variable costs. High crop density increases the humidity within the crop canopy, which enhances the environmental requirements for Botrytis spp. and Ascochyta spp. development. Within a season or specific crop, disease pressure increases as plant population increases. The actual population at which disease levels increase will alter for different crops grown in different seasons but the requirement for (mostly preventative) fungicides will increase as plant population increases.

 

Lodging pressure also increases with increasing crop density. The specific population at which the crop begins to lodge will differ in different sites and seasons. A similar experiment conducted in Elgin, near Aberdeen with Bourdon demonstrated a linear increase in crop lodging over a plant population of 14 plants per m-2.

 

The response of field beans to soil moisture may explain why soil conditions are an important determinant of yield. Research at Nottingham University during the 1980’s showed that crops established in compacted soils develop small, shallow root systems that exploit a smaller volume of soil and take up less water than those grown in a well structured soil. Yields were reduced by up to 15% in experiments over a number of seasons. Winter beans are suited to soils with good water holding capacity and generally yield better in heavy clays than on light, drought prone land.