• 
  Micronutrients
  • Nitrogen (N)
  • Phosphorous (P)
  • Potassium (K)
  • Magnesium (Mg)
  • Calcium (Ca)
  • Sulphur (S)
  • Boron (B)
  • Copper (Cu)
  • Cobalt (Co)
  • Iron (Fe)
  • Manganese (Mn)
  • Zinc (Zn)
  • Chloride (Cl)
• 
  Advice by Sector
  • Cereal Crops
  • Oil Seed Rape
  • Potatoes
  • Sugar Beet
  • Pulses, Peas, Beans & Soya
  • Vegetables, Melons & Salad Crops
  • Top and Soft Fruit
  • Grassland / Pasture
  • Amenity & Sports Turf
  • Home & Garden
• 
  Identifying & Rectifying Deficiencies
  • The Effect Of Soil pH On Nutrient Availability
  • Soil Type, Condition And Likely Deficiencies
  • Crop Susceptibility
  • Typical Deficiency Symptoms by Nutrient

OPTIMUM SPRAY TIMING

® Optimum time for application     ¦ Application Useful

Sulphur

Oilseed rape demands a high level of sulphur the uptake of which is linked with nitrogen uptake. It is an essential element in the production of proteins and glucosinolates. It also greatly affects pollen production. Soil and tissue analysis can often be inconclusive where deficiencies are slight and so maintenance applications of 50-80 kgSO₃/ha sulphur (20-32 kg S/ha) are desirable where deficiency is likely. This should be applied in early spring to coincide with nitrogen uptake. Where sulphur deficiency is confirmed the rate should be increased. In cases where sulphur application has been delayed and immediate uptake is required sulphur should be applied in sulphate form (e.g.  Ammonium Sulphate).

Sulphur deficiency can be a particular problem with hybrid rape as pod set can be seriously affected. When growing this crop sulphur rates should be increased according to breeders' recommendations.

Sulphur deficiency becomes apparent as pale inter-venial chlorotic mottling on the earliest (lowest) growth, to pale flowers and inhibited pod set in severe cases.

Oilseed Rape requires approx. 20 kg/ha of S in the autumn/early spring, before main S applications with N top dressings in the spring

Sulphur applications should be as a programmed approach:

ŸMicromix 900SS prilled Bentonite pastilles applied at drilling can supply the initial S requirements of the crop through autumn and early spring.

ŸFirst Nitrogen application should be a Nitrogen + Ammonium Sulphate product, and on lighter soils, a further foliar S may be needed.

ŸThe crop has established particularly well this autumn, and we could well expect S deficiency to be seen even earlier this spring as the crop tries to grow away with a strong canopy developing.

ŸIf pale flowers or leaf margin whitening are observed then immediate remedial action is required and a high dose (10L/Ha) of Thiosulphate formulations such as Sulphasol appear more active than elemental sulphur or other sulphates for this purpose.

Magnesium

Although the crop has a high requirement, visible deficiency symptoms are rare. Occurs most frequently on light and acid soil. Older leaves show interveinal bleaching, later turning to orange or red speckling. Can cause leaf death if uncorrected. It has become more common in recent years due to min-till and autocast establishment methods, coupled with the use of ammonium sulphate as the main nitrogenous fertiliser. In the autumn good results have been seen with Amix Magnaphite a magnesium phosphite which not only supports magnesium nutrition but also promotes root growth and sees plants establishing full ground cover quickly to deter pigeon damage.

Manganese

Manganese deficiency is common on alkaline soil types as it can be caused by high pH (lime) levels (6.5-8.0). It should be treated with a foliar manganese spray which restores levels rapidly and effectively. Manganese is crucial on high organic (black) soils where susceptibility to winter-kill is reduced massively by an autumn manganese supplement like Amix Manganese or BroadAcre Rape and Pulse Mix provides a sound base to create healthy disease resistant over-wintered plants, and follow-up spring treatments require less critical timing and generate bigger responses as a result.

Care must be taken when diagnosing manganese deficiency as the symptoms are often confused with those of sulphur deficiency. However a distinction can be made as the interveinal chlorotic marbling characteristic of the deficiency occurs on the newest growth and the whole plant appears limp.

Copper

Acute deficiency shows as interveinal bleaching, spreading to the whole leaf later. High risk situations similar to Manganese.

Molybdenum

Deficiencies occur on acid, non-chalky soils. Symptoms are yellowish interveinal blotches and malformation of the leaves, including curling leaf margins and stunting. Many plants will suffer with sub-clinical molybdenum deficiencies, and so greater responses are seen to Borimol and BroadAcre Rape & Pulse Mix than might have been expected from the observed deficiencies.

Boron

Rape has a very high Boron requirement relative to other crops. Soil testing should be carried out to establish the need for Boron, as overdosing can damage sensitive crops in the rotation, such as cereals. Insurance dressings are recommended when available boron levels are below 0.5 mg/². Boron leaches readily on lighter soils and it is preferable to apply it in split applications where deficiency is severe.

Symptoms vary with the severity of the deficiency, and those where the deficiency is minor (flower distortion and poor seed set) may be confused with other, more common disorders of oilseed rape. Typical symptoms show as early stunted growth and chlorotic, rolled leaves. Commonly there is also a 'dead heart' in the root core. As with sugar beet, the young plant stage is the best time to look for the symptoms, as when split longitudinally with a sharp blade, deficient plants show a clear dark thread descending from the point where stem becomes root, down the centre of the taproot

Borimol provides liquid Boron with molybdenum and can be safely applied at any stage of the crop.. The use of BroadAcre Rape & Pulse mix plus additional Boron will benefit OSR. Boron should not be applied in conditions of high temperature and/or light intensity.