about sulphur

Status of Indian Soils

Sulphur status of Indian soils is going down with each passing year. Close to 70% of soil samples analyzed by the ICAR system, TSI-FAI-IFA project and other programs have been found to be either deficient or marginal in plant available sulphur.

 

Sulphur Deficiencies at Country Level

In the early 1990s, sulphur deficiencies in Indian soils were estimated to occur in about 130 districts. More recently, soil fertility surveys by the ICAR system (analysis of 60,000 soil samples) have shown sulphur deficiencies to be a widespread problem. A soil is considered deficient in S if it tests less than 10 mg S/kg soil extractable with 0.15% CaCl2.

 

A = 45% districts having more than 40% soil samples deficient in S

B = 40% districts having 20-40% soil samples deficient in S

C = 15% districts having less than 20% soil samples deficient in S

 

Soil analysis and crop response data generated by the TSI-FAI-IFA project (1997-2006) re-enforced the findings of the ICAR system. Based on reported results, out of over 49,000 soil samples analyzed across 18 states, 46% of samples were deficient in sulphur and another 30% were medium in available sulphur which could be considered as potentially sulphur deficient. Soil sulphur deficiencies were encountered in all parts of the country. These data prove that sulphur deficiencies are a critical problem in 40-45% of districts translating into 57-64 million ha of net sown area. State-wise sulphur scenarios are available:

 

Major Reasons for Sulphur Deficiency in India

Several factors contribute to the growing incidence of S deficiency in India.

  • Increased in agricultural production are increasing the loss of sulphur (and other nutrients) Foodgrain production increased 120 million metric tons between the early 1980s and 2000.
  • Farming practices (removing stover/straw in addition to grain) increased net depletion of soil sulphur.
  • Low level of fertilizer use in general on pulses and oilseeds that have a higher requirement of sulphur than cereals per unit of grain production. These crops occupy 51 million hectares or almost 27% of the country's gross cropped area.
  • Distinct possibility of sulphur losses through leaching and runoff with the spread of flood irrigation to large areas, and in areas receiving heavy rainfall.
  • A fertilizer use pattern dominated by sulphur-free fertilizers: urea, diammonium phosphate (DAP), muriate of potash(MOP), and sulphur-free NP/NPK complex fertilizers. This not only excludes the addition of sulphur, but accentuates its depletion through the crop produced with NPK.