作物的营养.pptVIP

作物的营养 Reading for class Mineral Nutrition Nitrogen and minerals Crop residues Essential Plant Minerals 16 essential elements C, H, O – air and water, photosynthesis P, K, S, -- major elements Ca, Mg – lime elements Fe, Mn, B, Mo, Zn, Cu, Cl, Na – micro or minor elements I and Co important for animals Nitrogen Sources: Soil Organic Matter (5% N) – soil supplying capacity SOM Fertilizers – urea 46-0-0 Ammonium sulphate – 20-0-0 + sulphur Manures (compost) – external inputs Nitrogen transformations Nitrogen 78% in the air Rhizobial bacteria associations with roots – legumes and greenmanures Mobile element – easily leached Important for amino acids, proteins and many enzymes, hormones and other biochemicals Phosphorus Source: Soil minerals to soluble phosphatic acids External inputs Triple super phosphate 0-46-0 Diammonium phosphate 16-46-0 Nitrophos – 20-20-0 Rock phosphate – slow release Organic phosphates released from SOM Phosphorus P - Fixation in soils – an immobile element P - placement and banding Important in nucleic acids (RNA and DNA), proteins, phospholipids, ATP (energy) Potassium Source: Clay minerals – NYS soils high illite, so rarely deficient External inputs Potassium Chloride – 0-0-60 Complex or complete 10-10-10 etc. Manures and composts Potassium Partly mobile and can be leached Accumulates in growing tissue Activates enzyme systems Important in translocation sugars but role not precisely known Mobile in the plant Luxury accumulation Sulphur Source: Contaminant in air and fertilizers Sulphates – ammonium sulphate Organic matter Soil minerals Not very mobile in the plant Important some AA’s, proteins, enzymes Other elements Calcium – cell wall, membranes, cell division, enzymes, pH adjustment Magnesium – chorophyll, catalyst for enzymes Iron – enzymes, Photosynthesis, heme proteins Boron – carbohydrate translocation, sterility Manganese -- enzymes Copper -- enzymes Zinc -- enzymes Molybdenum – nitrogen fixation, enzymes Critical levels