Establishing oilseed rape crops this autumn has been challenging; particularly in eastern counties where dry conditions have hampered germination and early growth and exacerbated attacks from flea beetle.

The AICC (Association of Independent Crop Consultants) has conducted a survey amongst their members to ascertain the extent of damage to OSR crops this autumn. Agronomists were asked to record the percentage of the crop under their control that had been written off as a result of dry conditions or flea beetle attack. 

Over 70 AICC agronomists based along the eastern seaboard stretching from Northumberland to Kent, representing over 77,000 hectares of OSR responded to the survey. Typically this area represents 70% of the UK oilseed rape crop. 

Dry weather takes its toll

The survey identified a particular problem in five key counties. Hertfordshire and Essex were particularly badly hit with losses averaging 45%.

The most severe losses were recorded from the counties in the south and east, namely Northants, Beds, Essex, Cambridgeshire, Suffolk, Herts and Kent. Across the area under study around 14% of the crop has been written off due to lack of moisture.

Flea beetle losses too.

Flea beetle damage was less severe but no less important in Hertfordshire (33%) and Bedfordshire (29%). In Essex 16% of the crop has been written off due to flea beetle damage. Cambridgeshire and Northants recorded 12% lost and in Hampshire and Oxfordshire losses were recorded at around 10%.

It is estimated that around 7% of the national oilseed rape crop has been written off as a result of the flea beetle damage.

Overall, it is estimated that as many as 40,000 hectares of OSR crops this autumn have been lost as a result of poor germination and crop establishment due to dry seedbeds and a further 30,000 hectares lost due to flea beetle damage. 

SMD figures reveal severe conditions.

The met-office soil moisture deficit figures for the UK as of Tuesday 25 October show a very parched region in the SE of England (see diagram below). The Institute of Hydrology, Wallingford, Oxon, determine wet soils as those having a soil moisture deficit of less than 10 mm (SMD60mm). The met office consider that soils in the SE with SMD of over 130 mm are at or near their SMD Max that is at or near permanent wilting point. The highest SMD figure this week in the region has exceeded that point.

Andrew Blazey of Prime Agriculture LLP that covers the whole of East Anglia, notes that  choosing a replacement crop for failed OSR  is not easy.  “It has been a tricky balancing act weighing up the need to maintain first wheats in the rotation, the combine capacity for the next harvest, how regularly pulses have been grown in the past, the soil type of the farm and the need to maximise profitability.  The result being that no one crop has suited all situations, and must be looked at on an individual field and farm basis.”

Map showing areas by soil moisture deficit levels. Source Met-Office MORECS data.

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