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Review Physical properties of soils?? Review Physical properties of soils?? Soil texture Soil structure Density Review Chemical properties of soils?? Review Chemical properties of soils?? pH CEC Review Chemical properties of soils?? pH CEC What is the pH of agricultural soils? Review Chemical properties of soils?? pH CEC What is the pH of agricultural soils? between 6 and 7 Review Chemical properties of soils?? pH CEC What is the pH of agricultural soils? between 6 and 7 Why is this range the optimum condition? Plant Nutition Introduction How many elements do we find in plants? Do plants need all the elements in the same amount? How does agriculture effect the soil nutrients? What is the solution? Introduction 60 or more elements are found in plants. 17 essential Introduction 60 or more elements are found in plants. 17 essential Macronutrients Micronutrients Enzyme cofactors Macronutrients Introduction 60 or more elements are found in plants. 17 essential Macronutrients Micronutrients Enzyme cofactors Micronutrients 60 or more elements are found in plants. Macronutrients Micronutrients 17 essential Enzyme cofactors What is the relationship between plant nutrition deficiency and humans or animals? China example Nitrogen Nitrogen role in plants Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins) Nitrogen Nitrogen role in plants Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins) Nitrogen Nitrogen role in plants Protein Base pairs for RNA/DNA Chlorophyll Hormones (ABA, cytokinins) 2% of DW Which type of transport requires ATP? Nitrogen deficiency Poor, stunted growth with pale leaves and weak stems. Leaves often turn orange or red, may fall prematurely. Fruit trees Vegetables Phosphorus ATP/ADP DNA/RNA Phospholipids Membrane Phosphoproteins 10% of N Phosphorus Deficiency Poor growth Fruits are small and acid tasting Leaves become brown or red if P is severely deficient. Corn and grassy plants Oldest leaves are affected first Potassium Cofactor in osmosis Stomata control Protein synthesis Deficiencies: Dull and spare flowers Low fruit yield and poor quality. Tissues become soft and susceptible to attack from pests. Brown scorching and curling of leaf tips, and yellowing of leaf veins. Purple spots may also appear on the leaf undersides. Iron Enzyme activator Required for chlorophyll synthesis When soils are alkaline, iron may become unavailable. Applications of an acid nutrient formula can help. Zinc Energy production Protein synthesis Formation of chlorophyll Growth regulation Deficiency Symptoms: Delayed maturity Symptoms occur mainly in new growth Short internodes Decrease in leaf size Soil, Water and Minerals Silicates (SiO4-4)93% of earths crust Rings of water form around soil particles. Soil solution • Cations and Anions dissolve in water. • 50% of soil vol. Soil, Water and Minerals What are some factors in ion binding to soil particles? • Charge ( + & - ) • Size • Concentration Soil, Water and Minerals Ca2+ vs. Na+ High conc. of Na+ vs. Low conc. of Ca2+ Soil, Water and Minerals Why is it important to know these rules? • Salty soils – high levels of Na+ • Useful ions end up in ground water • Southwestern US Acidic Soils Acidic soils are nutrient poor. Where do we find acidic soils? Why? Acidic Soils Acidic soils are nutrient poor. Where do we find acidic soils? Why? CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3H+ displaces other cations. Acidic soils bring toxic ions into the soil solution Aluminum ions Cation Exchange • CO2 released from roots (indirect H+) • H+ can also be secreted (direct) • H+ then replaces the mineral cations in soil • Minerals are released • Roots uptake the minerals Nitrogen Why is Nitrogen important for plants? Nitrogen Why is Nitrogen important for plants? Proteins, DNA, RNA, chlorophyll, and hormones Nitrogen Why is Nitrogen important for plants? Proteins, DNA, RNA, chlorophyll, and hormones Do you remember the symptoms of nitrogen deficiency? Nitrogen Why is Nitrogen important for plants? Proteins, DNA, RNA, chlorophyll, and hormones Do you remember the symptoms of nitrogen deficiency? Poor growth Weak stems Discoloration of leaves Nitrogen and Bacteria • N2 can not be used directly by plants • NO3- or NH4+ • Nitrogen fixation – Soil bacterial Rhizobium – The conversion of N2 into NO3- or NH4+ • Legumes are rotated with other crops to enrich the soil. Nitrogen Fixation by Bacteria Review • Macro and Micronutrients – Importance to plants – Deficiency symptoms • Ion and soil particle interactions • Cation exchange • Nitrogen fixation