My card marks zinc and sulphur as deficient, how do I act on it?

A deficiency mark means your soil is short of that micronutrient and the crop is likely to suffer if you do not correct it. For zinc deficiency the usual fix is to apply zinc sulphate as a basal dose at sowing, mixed in the soil, in the quantity your card recommends, and you can also give a foliar spray of zinc sulphate with a little lime if the crop already shows symptoms. For sulphur, the common sources are gypsum, single super phosphate (SSP) which carries sulphur, or elemental sulphur and ammonium sulphate, applied as basal per the recommended rate. Two important habits. First, follow the quantity printed on your card or given by your lab and KVK, micronutrients work in small amounts and over-applying zinc can itself cause problems. Second, do not mix zinc and phosphatic fertilisers in a way that locks them up, your KVK can advise the right combination and timing. Correcting zinc and sulphur often gives a clear yield response in cereals and oilseeds. Confirm the exact rates and product for your crop with your KVK, and do not over-apply.