Tamil Nadu

• Nitrogen

  From 6,52,652 soil tests

  Poor
  Low 99% Medium 1%

  Almost every soil test here came out low

  If your field is low: add about a quarter more urea than the usual dose, in two or three splits. A pulse crop in rotation also adds nitrogen.

  What this means

  Grows leaves and stems. Short soil gives pale, yellow leaves.

  Low under 280 kg/ha Medium 280–560 kg/ha High over 560 kg/ha

  Healthy soil has 280 kg/ha or more.

• Phosphorus

  From 6,52,780 soil tests

  Okay
  Low 21% Medium 43% High 36%

  2 in 10 soil tests here came out low

  If your field is low: add about a quarter more DAP or single super phosphate than the usual dose, at sowing.

  What this means

  Builds roots and helps the crop flower and fill grain.

  Low under 10 kg/ha Medium 10–25 kg/ha High over 25 kg/ha

  Healthy soil has 10 kg/ha or more.

• Potassium

  From 6,52,914 soil tests

  Good
  Low 11% Medium 43% High 46%

  1 in 10 soil tests here came out low

  What this means

  Fills grain and fruit, and helps crops stand drought and disease.

  Low under 110 kg/ha Medium 110–280 kg/ha High over 280 kg/ha

  Healthy soil has 110 kg/ha or more.

• Organic carbon

  From 6,52,236 soil tests

  Poor
  Low 88% Medium 9% High 3%

  9 in 10 soil tests here came out low

  If your field is low: add 4 tonnes of compost or farmyard manure per acre before sowing, and plough crop leftovers back in instead of burning them.

  What this means

  Shows how much organic matter the soil has. It keeps soil loose, holds water and feeds the crop slowly.

  Low under 0.5% Medium 0.5–0.75% High over 0.75%

  Healthy soil has 0.5% or more.

• pH

  From 6,51,187 soil tests

  Good
  Acidic 2% Neutral 93% Alkaline 5%

  Almost no soil tests here fell short

  What this means

  How sour (acidic) or alkaline the soil is. It decides which nutrients roots can take up.

  Acidic Neutral Alkaline

  In these tests, neutral means about pH 6 to 8, which suits most crops; acidic is below about 6 and alkaline above about 8.

• Salt

  From 6,51,905 soil tests

  Good
  Not salty 98% Salty 2%

  Almost no soil tests here came out salty

  What this means

  Salt in the soil, shown as EC on the card. Salt makes it hard for roots to drink.

  Not salty Salty

  Under 1 dS/m is fine. Between 1 and 4, only crops that can't take salt lose yield. Above 4 harms most crops.

• Sulphur

  From 6,52,918 soil tests

  Okay
  Short 35% Enough 65%

  4 in 10 soil tests here came out short

  If your field is short: use single super phosphate instead of DAP, or add about 100 kg of gypsum per acre before sowing.

  What this means

  Makes oil in oilseeds and protein in pulses.

  Short under 10 ppm Enough 10 ppm or more

  Healthy soil has 10 ppm or more.

• Zinc

  From 6,52,767 soil tests

  Okay
  Short 42% Enough 58%

  4 in 10 soil tests here came out short

  If your field is short: mix 10 kg of zinc sulphate per acre into the soil before sowing. One dose lasts two or three seasons.

  What this means

  Needed for growth and healthy leaves. Rice and wheat often run short.

  Short under 0.6 ppm Enough 0.6 ppm or more

  Healthy soil has 0.6 ppm or more.

• Iron

  From 6,29,890 soil tests

  Okay
  Short 37% Enough 63%

  4 in 10 soil tests here came out short

  If your field is short: spray ferrous sulphate, 5 g per litre of water, when young leaves turn yellow.

  What this means

  Keeps young leaves green.

  Short under 4.5 ppm Enough 4.5 ppm or more

  Healthy soil has 4.5 ppm or more.

• Copper

  From 6,51,778 soil tests

  Good
  Short 3% Enough 97%

  Almost every soil test here had enough

  What this means

  Helps the crop set seed and resist disease.

  Short under 0.2 ppm Enough 0.2 ppm or more

  Healthy soil has 0.2 ppm or more.

• Manganese

  From 5,96,179 soil tests

  Okay
  Short 22% Enough 78%

  2 in 10 soil tests here came out short

  If your field is short: spray manganese sulphate, 5 g per litre of water, on the young crop.

  What this means

  Helps leaves make food from sunlight.

  Short under 2 ppm Enough 2 ppm or more

  Healthy soil has 2 ppm or more.

• Boron

  From 6,52,816 soil tests

  Okay
  Short 45% Enough 55%

  5 in 10 soil tests here came out short

  If your field is short: mix 4 kg of borax per acre into the soil before sowing.

  What this means

  Needed for flowers to set seed and fruit.

  Short under 0.5 ppm Enough 0.5 ppm or more

  Healthy soil has 0.5 ppm or more.

Fixes are the usual advice. Your Soil Health Card or nearest Krishi Vigyan Kendra gives the exact dose for your field.