The study noted that mustard crop, which is usually grown on marginal lands highly deficient in sulphur. The average productivity of mustard in India is normally around 900 kg per hectare as against the world average of 1500 kg per hectare.

This low productivity is largely attributable to the deficiency of sulphur as a micro-nutrient required by the mustard crop for optimum growth, development and yield. The deficiency of sulphur in the soil where mustard crop is usually grown has been earlier established by a survey carried out jointly by FAO and ICAR. The lower yield of mustard crop owing to the deficiency of sulphur is linked to the strong interaction of sulphur and nitrogen at the metabolic level.

The improved nutrient management protocol leads to the optimisation of seed and oil yield as well as an improvement in the quality of oil and oilcake. The protocol recommends the inclusion of sulphur with other macro-nutrients like nitrogen, phosphate and potassium. Additionally sulphur and nitrogen are given in balanced and split doses at the appropriate phenotypic stage of the crop. The split dosage prescribed by the protocol ensures that adequate levels of sulphur and nitrogen are maintained in the soil and are supplied to the crop throughout its growth period especially during the crucial reproductive stage. It has been established that this period is highly sensitive to nutrient imbalance.

Under the protocol, 20 kg of sulphur, 50 kg of nitrogen, 40 kg of potassium and 40 kg of phosphate per hectare are applied to the soil as a basal dose at the time of sowing the crop. Subsequently 20 kg of sulphur and 50 kg of nitrogen per hectare are applied prior to flowering.

Field trials conducted using this nutrient protocol application has shown that the protein content of mustard seeds has increased by 6.5 per cent. The protocol also led led to a reduction in erucic acid content in oil by three to 8 per cent and glucosinolate content in oilcake by 20 to 45 per cent. Simultaneously linoleic acid and oleic acid, the saturated fatty acids present in the oil registered an increase.