Soil + Plant Nutrition

  • Vocabulary:

    • Humus: Decomposing biotic matter in soil

    • Green Revolution: Founded by Norman Morlock, caused the human population to skyrocket, led to much more efficient farming practices. During this revolution, craps resistant to disease were transported, and farms were revolutionized with machines. This ended up destroying the agriculture economy though, less localized

    • N-P-K: Stands for nitrogen, phosphorus, and potassium, on a bag of dirt described how much of each nutrient is in it

    • Phosphorus: Necessary for ATP, nucleic acids, and phospholipids

    • Potassium: Helps regulate turgor pressure

    • Nitrogen: Required for protein synthesis, chlorophyll, and nucleic acids

    • Depleted soils: Soils without sufficient N-P-K, common in places without sustainable farming practices

    • Copper: Aids in cell wall growth, aids in redox and lignin biosynthetic reactions

    • Enzyme cofactors: Metals/minerals that allow for enzymes to properly function

    • Soil management: Involves things like crop rotation to replenish the soil

    • Fertilization: Replaces mineral nutrients that have been lost from the soil

    • Algal blooms: Caused by overnutrition of soil and excess minerals, the algae make toxics and also block other organisms from getting oxygen

    • Organic fertilizers: Composed of manure, fishmeal, or compost, produce N, P, and K as they decompose (over time)

    • Soil texture: How compact or loose the soil is

    • Soil composition: What is the soil made out of, what are the particles

    • Loam: has equal amounts of sand, silt, and clay. This allows for drainage (to not block the plant from getting oxygen)

    • Soil bacteria: Allows for chemicals in the roots to be exchanged with the environment, the bacteria enhances decomposition

    • Rhizosphere: The area around the plant root, has high microbial activity due to high content of sugars, amino acids, and organic acids

    • Rhizobacteria: Bacteria that live in the rhizosphere, some can enter roots

    • Nitrogen cycle: Transforms atmospheric nitrogen and nitrogen-containing compounds, nitrogen is only absorbed as NO3- or NH4+, bacteria make this nitrogen usable, done by nitrogen-fixing bacteria

    • Ammonifying bacteria: Turns amino acids into ammonium

    • Mycorrhizae: Fungi that form symbiotic/mutualistic relations with roots, fungi gain a steady supply of sugar but help roots of the plant get water and nutrients

    • Ectomycorrhizae: Grows on the outside/in between the cells

    • Endomycorrhizae: Also known as arbuscular, invade the cell membranes past the cell wall

    • Parasitic plants: Plants that take sugars from other plants, only some photosynthesize

    • Carnivorous plants: Typically digest insects, developed due to a lack of protein. Attracted by odors, then trapped and digested with enzymes

  • Soil:

    • Many living organisms in it, as well as decomposing biotic matter (Humus)

    • Slightly acidic soil is better for growing plants, as the H+ cations replace the other cations required in the plant

    • Mostly water and dissolved minerals, with lots of air pores

    • The best soil has equal amounts of sand, silt, and clay

  • In corn, nutrient deficiency is easy to see. A N deficient leaf has a brown mid-vein, a P deficient reddish brown edges, and in K deficient leaves the edges are brown/yellow

  • Over time, crop yields decrease, due to soil depletion

  • Mycorrhizae:

    • Adaption between fungi and plants is co-related, they have evolved with each other and due to each other

    • They communicate with each other and share nutrients

    • Symbiotic, mutualistic

    • Early plants couldnā€™t get nutrients from soil on their own (no developed roots), so they formed these associations with fungi

    • Modern plants having these connections isnā€™t necessary for life, but greatly helps

    • Fungi serve as a connection point between plants and other plants

    • Can be ectomycorrhizae or endomycorrhizae

    • Ectomycorrhizae: Grows on the outside/in between the cells

    • Endomycorrhizae: Also known as arbuscular, invade the cell membranes past the cell wall

  • Plants can be parasitic, taking nutrients from other plants (for example mistletoe). This is the main source of sugars for these plants, some do their own photosynthesis while some donā€™t

  • Some plants can also be carnivorous (like the Venus fly trap, pitcher plants, or sundew). They likely developed due to living in an area with a lack of protein. These insects are typically attracted with odors, and then they are trapped (either a slippery surface into the plant, or sticky surface) and digested by enzymes