The following table summarises  research findings on the impact of S on yields of cereals, pulses and oilseeds under field conditions in different parts of India.

 Average crop responses to S application under field conditions

* Crops with 5 or more results included here

In other words, S applications on S deficient soils increased crop yield by

    32% in Groundnut                   25% in Soybean                  20% in Sunflower
     30% in Mustard                       22% in Pigeonpea              17% in Rice
     25% in Wheat                          20% in Greengram             16% in Linseed

Such response rates are significant, comparable to those obtained from other major nutrients and are highly profitable.

Sulphur, the ”yield+quality nutrient” improves crop quality in many ways: Increasing the oil content of seeds. Increasing protein percentage in plants and harvested produce. Improving nutritional quality of forages by providing a balanced  N:S ratio. Improving starch content of tubers. Improving baking quality of wheat. Increasing sugar recovery in sugar-cane. Enhancing market-ability of copra (coconut  kernel).

In India, S is most frequently identified with improvement in oil content of oilseed crops. In fact, each kg of S applied can increase the supply of edible oil by 3.0-3.5 kg. The production of oilseeds is much below the requirement, a gap which sulphur fertilisation can help to fill. Some estimates of increase in oil content of oilseeds are provided in the figure below.

Average impact of S application on oil content of seeds as compared to no-S plots is shown in the diagram above. Figures in (   ) indicate studies averaged. Apart from field crops, results from Tocklai Tea Experiment Station, Jorhat, Assam show the beneficial effect of S on improving tea quality. Application of 20 kg S/ha improved tea quality rating from 61.0 to 74.0 (+ 21%).

The fact that S is the cheapest of the four major nutrients (N, P, K, S) is not widely appreciated. This means that (i) sulphur application is highly profitable, (ii) at similar rates of response, profits from S are higher than from other major nutrients, (iii) being least expensive, S has lowest break-even point (units of produce needed to pay for one unit S) and (iv)
lower response rate needed in the case of S for an acceptable Value:Cost Ratio (VCR) of 2.5. Click here for more

Sulphur interactions both synergistically and antagonistically with other nutrients. In most cases, S  acts synergistically with N, the most often applied nutrient. Both N and S improve each other’s efficiency  and their combined impact on yield and nutrient recovery by crops is bigger than the sum of their individual effects. In case of P, the nature of interactions depends of the rate of application which is a reflection of whether the two nutrients are balanced or not. The interaction of S with Mg and B can be positive or negative but in the case of oil crops, it is more clearly evident in oil yield than in seed yield. Out of the total reponse of groundnut to S and B application, the synergistic effect contributed 22% to the increase in  kernel yield but 43% to the increase in oil yield.

Also Look for

• Sulphur in the News and Press
• Sulphur – The 4th Major Plant Nutrient
• Sulphur Status of Indian Soils
• Sulphur and Agricultural Production
• Sulphur Fertilisers
• TSI India Programs