Nitrogen, Phosphate, Potash and Magnesium

Beans do not require applied nitrogen even on backward or poorly developed crops.
Little or no response is seen to applied P or K above index 2. Amounts of phosphate and potash are based on a yield of 3.5t/ha and any fertiliser that needs to be applied should be broadcast and ploughed in for winter beans.
Secondary nutrients and trace elements should be applied as and when deficiencies occur. Manganese is probably the most common trace element deficiency seen. Apply manganese as you go through with the fungicide programme. For maintenance levels, apply 2.5kg/ha manganese sulphate or 2.5-3 lt/ha of a 17.5% liquid manganese sulphate at both fungicide timings. If manganese sulphate is applied by itself, add the correct rate of non-ionic wetter. If deficiency is very visible, add manganese sulphate at 5.0kg/ha + appropriate rate of non-ionic wetter or 17.5% manganese sulphate at 5.0Lt/ha. Beans have a high S requirement.

Phosphate, Potash and Magnesium Requirement (Beans and Peas)

INDEX	0	1	2	3	Over 4
	Kg/ha	Kg/ha	Kg/ha	Kg/ha	Kg/ha
Phosphate	85	60	35	0	0
Potash	90	65	40M(2) 20(2+)	0	0
Magnesium	100	50	0	0	0

MAFF RB209

Seedbed phosphate and potash only needed at Index 0 and 1.
M indicates a maintenance dressing intended to maintain soil reserves and prevent depletion of soil fertility rather than give a yield response.
Please allow for nutrients from any applied organic manure. The amounts of phosphate and potash are for a 3.5t/ha yield of beans. Adjust accordingly for expected increase or decrease in yield. If there is no long term build-up soil P and K at Index 0 or 1, the recommendation may be reduced by 50kg/ha at Index 0 and 25kg/ha at Index 1.

Sulphur
Beans do respond to an application of sulphur if a deficiency is apparent.
Light and free draining soil is most likely to be affected. If you are applying sulphur to all cereal and rape crops then it is likely the bean crop will also benefit.
For beans an N:S ratio of 20:1 is required. Sulphur needs to be applied pre-drilling and will require in the region of 30-50 kg/ha SO3. Gypsum or Kieserite at 20kg/ha or ammonium sulphate at 80kg/Ha will supply adequate amounts. The amount of N in the ammonium sulphate will have no effect on the crop. Ammonium sulphate costs approx. £2-3/ha. Foliar treatments with powdered sulphur (e.g. Thiovit at 10kg/ha) will offer something but will not be as good as soil applied sulphur. The amount of available sulphur is not great and it will need time to break down to a form useable by the plant. This approach will also be more costly.