Soil Science and Agriculture

Nutrient deficiency and toxicity disorders in plants 1. Nitrogen (N) Deficiency: Buttoning in cauliflower  Toxicity: Hollow stem in cauliflower 2. Phosphorus (P) Deficiency: Sickle leaf disease 3. Potassium (K) Deficiency : Yellow white mottling of cotton Firing of tobacco leaves Toxicity : Blotchy ripening of tomato (K excess & N imbalance)  4. Calcium (Ca) Deficiency : Blossom end rot in tomato Bitter pit in apple Pillow diseases of cucumber Die back disease of pea  5. Sulphur (S) Deficiency : Tea yellow diseases   6. Magnesium (Mg) Deficiency : Reddening of leaves in cotton Sand drawn diseases in tobacco Grass tetany (animals)   7. Iron (Fe) Deficiency: Papery white (complete whiteness of leaves) Yellowing of groundnut White eye of rice Leaf bleaching in sugarcane Ivory white of paddy Toxicity: Browning of   rice Bronzing in leaf blade rice (>300 ppm) 8. Manganese (Mn) Deficiency: Sugarcane blight Pahlala blight of sugarcane Marsh spot of pea Grey

  The science of using front-line sensor and analysis systems to enhance crop yields and support management decisions is known as precision agriculture. A novel idea called precision agriculture has increased widespread recognition in order to boost output, shorten labor hours, and assurance efficient fertilizer and irrigation management. It makes widespread use of data and information to raise crop yields and quality while better utilizing agricultural resources. With the introduction of the “green revolution” during the 1960s high yielding varieties and hybrids were introduced, and thereby application of higher doses of fertilizers was initiated. By interpretation of soil test ratings, the soil testing laboratories adjusted fertilizer recommendations by increasing and decreasing the recommendation level by 30-50 percent based on low or high fertility levels. Even though it is a good method, it cannot be generalized for all crops and all soils. In order to achieve higher and sustained

Phosphorus fixation is the conversion of soil solution phosphorus to insoluble compounds by the soil components, causing a reduction in the amount that plants can absorb. Phosphorus availability is usually greatest in slightly acidic to neutral soil (pH 6-7). The amount and manner in which soluble phosphorus is fixed is influenced by the pH of the soil solution. Between pH 4.0 and 8.0, the main phosphate ions in soil are H 2 PO 4 - and HPO 4 2- . PO 4 3- predominates above pH 9.0, but H 2 PO 4 - is still present. The extent of problems of phosphorus fixation in India The efficiency of phosphatic fertilizers in India is around 15 to 20 percent because of their fixation in acidic and alkaline soils, and unfortunately, both soil types lead in India, accounting for more than 34% acidity affected and more than 7 million hectares of productive and fertile land salinity/alkalinity affected. Phosphorus fixation is greater in black, red, laterite, mixed red and black, red and yellow, and coast