Crops notes Nov 04

The unseasonable weather during October has prolonged the potato harvest. Extra care is now needed during late harvesting as cold potatoes damage more easily. Check soil temperatures and avoid harvesting in cold conditions as potatoes are much more susceptible to bruising below 100C. If soil temperature falls below 50C stop harvesting altogether.

Check damage levels regularly, for both external damage and bruising, so that all stages in handling can be assessed to ensure minimal damage.

Handle potatoes as gently as possible and check that the harvester is correctly set and that any parts of the harvester that could cause damage are altered. Make every effort to maintain a good soil cushion on the main web of the harvester, minimise agitation and reduce drop heights.

Minimise the drop between the harvester cart elevator and the bulk trailer or box. Fall breakers or padded landing areas should be used to reduce impacts.

To reduce the development of skin blemish diseases such as silver scurf and soft rots, tubers should be dried as quickly as possible after lifting. Drying immediately for at least 48 hours using positive ventilation systems has been shown to significantly reduce the development of silver scurf. If soft rots are present, this drying time may need to be increased to at least 96 hours.

This season attempt to continue drying throughout the curing period. The more the crop is dried, the lower the risk of rotting. The wound-healing period should be kept to a minimum of two weeks. Humid air in the store should be changed by ventilating on dry afternoons. Crops that contain more than 1% blight or soft rots should not be cured but marketed as soon as possible as there is a high risk of widespread rotting during storage.

Following curing, store temperature should be reduced slowly by approximately 0.50C per day to the desired holding temperature. The recommended storage temperature depends on the end use and length of storage period. If possible continue to ventilate periodically throughout the storage period as a precaution against rots, or at least regularly inspect the store and remove any problem material immediately.

It is now past the optimum sowing date for winter barley. Even with increased seed rates, crops drilled from November onwards may not produce high enough yields to justify sowing winter barley in preference to waiting for 5-6 months and sowing a spring variety.

Wheat is much more tolerant of later sowing than barley or oats and can be sown successfully into the new year with varieties which require low levels of vernalisation. However, seed rates should be increased to combat the effects of lower soil temperatures, cloddy seedbeds and pest attacks which combine to reduce the percentage plant establishment as sowing is delayed.

Seed rates of between 400-500 seeds/m2 would be appropriate for sowings in November with the higher seed rates being used in more difficult conditions if sowing date gets further delayed. This would translate to seed rates in the range of 180-225kg/ha (11.5-14 stone/ac) if a variety with a Thousand-Grain Weight of 45g were being sown.

DARD Farm Management Notes for November 2004 have been prepared by Greenmount Campus, College of Agriculture, Food and Rural Enterprise - Tel: 028 9442 6771. We acknowledge the contribution from Veterinary Service. For further information contact your local DARD Development Adviser.