Your crop is Molybdenum deficient.

• Molybdenum is essential for the process of symbiotic nitrogen (N) fixation by Rhizobia bacteria in legume crops.
• Molybdenum is needed by the plant in the synthesis and activation of nitrate reductase enzyme which reduces nitrate to ammonium in the plant.
• Several materials supply Mo and can be mixed with NPK fertilizers applied as foliar sprays or used as a seed treatment.
• Form used by plants: MoO4-2