ELEMENTS	DEFICIENCY SYMPTOMS	REMEDIAL MEASURE
NITROGEN	Plants are stunted and yellow in appearance. Stems are thin and elongated. The stem turns reddish. Yellowing or chlorosis appears first on the lower leaves; the upper leaves remain green. The tendency of the young upper leaves remaining is due to the remaining nitrogen moving towards the newly growing leaves.	Among the available nitrogenous fertilizers, ammonium sulphate is preferred for groundnut crop because of its sulphur content (24%).
PHOSPHOROUS	Mild deficiency of P are usually characterized by stunted growth of plants with no very clear-cut leaf symptoms Most severe deficiencies result in dark green leaves with a leathery texture, and reddish purple leaf and margins	About 25-50 kg P2O5/ha has been recommended for different groundnut-growing regions in the country.  It has been found that single super phosphate is the best source of phosphorus as it contains calcium (19.5%), sulphur (12.5%) and phosphorus (16%)
POTASSIUM	Lack of potassium causes stunted plants with small branches and little vigor K deficient plants exhibit chlorosis or yellowing along the leaf margins or tip starting with the bottom leaves & progressing up the plant. In severe cases, the leaves appear dry and scorched at the edges and the surfaces are irregular chlorotic.	Normally, about 50 kg K2O/ha will be adequate for the soil deficient in potassium. Potassium may be supplied regularly in the form of potassium sulphate. All K2O should be applied at the time of sowing as a basal-dressing by adopting furrow placement method.
CALCIUM	Calcium is one of the less mobile nutrients in plants. In groundnut, there is very little translocation (movement) from the main plant body into the forming pods. This limitation, in calcium availability to developing pods leads to calcium deficiency. Clear foliar deficiency symptoms of calcium in groundnut are not known. The calcium deficiency is reflected in poor pod formation. So, there will be less number, and small ill-developed pods per plant.	Apply 250-500 kg/ha gypsum in the fruiting zone
SULPHUR	Sulphur deficiency is characterized by stunted growth, and general yellowing of plants. In some cases and interveinal pattern appears, the veins remaining green. Sulfur deficiency may also delay maturity of groundnut crop. An acute sulfur deficiency causes the entire plant to turn yellow. Yellowing of leaves also is characteristic of nitrogen deficiency. But, in this case, yellowing always starts with older leaves (bottom leaves) and proceeds upward.	Apply gypsum (250-500 kg/ha) through soil)
MAGNESIUM	The predominant symptom is dark green veins with yellow areas between the veins (interveinal chlorosis). The bottom leaves are always affected first. The branches will be weak and prone to fungus attack    As the deficiency becomes more acute, the symptoms progress up the plant. Chlorotic leaves generally turn red and then develop spotted necrotic areas.	Spray of foliage with 1% MgSO4 solution to correct the deficiency.
IRON	Iron (Fe) deficiency is common in calcareous soils (>7.5 pH) and in poorly drained soils. Legumes like groundnut are particularly sensitive to iron deficiency. The main symptom of iron deficiency is chlorosis or yellowing between the veins of new leaves. The chlorosis or yellowing between the veins also results due to zinc deficiency. Iron chlorosis extends to full length of leaves where as Chlorosis due to zinc deficiency occur mainly on the lower half of the leaves.
ZINC	Zinc deficiency also results in stunted growth, while young leaves are smaller than normal. Zinc deficiency symptoms may occur concurrently with Iron deficiency symptoms and the two can easily be confused. However Iron chlorosis extends to full length of leaves where as Chlorosis due to zinc deficiency occur mainly on the lower half of the leaves.	Apply 15 kg/ha or more Zn through soil; spray 10 kg/ha ZnSO4
BORON	The inner faces of the boron deficient groundnut cotyledons are depressed and discolored. This is classified as a form of internal damage and has been termed hollow heart. Necrotic areas are localized near the leaf margin. Soils with hot water extractable boron below 0.2 ppm are considered deficient	Spray 10 kg/ha borax or 0.2% borax through soil; foliar application of 0.1 ppm B at pre-bloom stage is advantageous
MOLYBDENUM	In legumes, including groundnut, a shortage of molybdenum affects the nitrogen-fixing activities of soil microorganisms. This results in less availability of nitrogen to the plants. Hence, the symptoms of molybdenum deficiency are similar to those of ordinary nitrogen deficiency.    Symptoms of molybdenum deficiency resemble those of nitrogen deficiency that is, yellowing of leaves, stunted growth, and low yield.
MANGANESE	The main symptom of manganese deficiency is chlorosis or yellowing between the veins of new leaves. There may also be a distinguishing characteristic of brown spots on the leaf margin (observe in the picture).	Apply 10 kg/ha manganese sulphate through soil; foliar application @ 0.12 kg Mn/ha is useful
COPPER	The copper (Cu) deficient plants are stunted and rosette. The stunted plants are green and wilted in early growth stage. The entire leaflet becomes cupped, and the leaflet margins turn upward. Some bronzing and necrosis of outer edge of the leaflet may occur.	Small amount of soil applied CuSO4 is able to correct the copper (Cu) deficiency on calcareous soils.   Apply 2 - 6 kg Cu / ha as copper sulphate once in 3 - 4 years. Application should be discontinued with Cu build up in the soil and those with 0.2 ppm Cu or more should not be fertilized with Cu.