Question

1 Normal 1 No Spac... Heading 1 Heading 2 Paragraph Styles We discussed that the top layer of soil is best for plant growth. Why? (Why during the Dust Bowl was the loss of the top layer so detrimental to the farming community? Why not just use what was left?). What characteristics of the top layer make it so great (water content? What living organisms do we find there? Etc.) We discussed the concept of Cation Exchange. What is cation exchange and what is its importance to plant nutrition? Are soil particles positively or negatively charged? What is the role of H+? Where does H+ come from (we discussed 2 ways plants can affect soil H+ concentration)? What does biologically available mean? What do you think would happen to negatively-charged nutrients (NOx) during a rain storm? Why? Why are slightly acidic soils better for plant nutrition than basic soils? What type of toxicity can occur in plants when soils are too acidic? + Understand the important macro-and micronutrients we discussed in class and what their function is in plants. What would happen if one of these nutrients was in limited amount? What type of experiment can you set up to determine which nutrient is limiting plant growth? Why would you even be interested in running an experiment like this? Are younger parts of a plant more or less likely to be affected when a mobile nutrient is in limited amount? What about less mobile nutrients? Why? What is a smart plant and what is its use in agriculture? + Over evolutionary timescales, some plants have adapted to their environments by becoming carnivorous. What type of environment would you expect to find carnivorous plants? What adaptations so pitcher plants have that allow them to successfully capture prey and digest it to obtain nutrients from it?

Answer 1

1.Plants generally concentrate their roots in and obtain most of their vital nutrients from this layer. Actual depth of the topsoil layer can be measured as the depth from the surface to the first densely packed soil layer known as subsoil.

Topsoil is more than just dirt, it is a living thing made up of countless microorganisms.The Earth is covered with an average of three feet of topsoil, the layer of dirt that provides the nutrients for most of the planet's land vegetation, and is critical for producing food from agriculture.Good topsoil maximizes crop yield while protecting the crop from degradation. The quantity of soil eroded is determined by multiple factors; including weather (wind and rain), the surface the soil (including the steepness on slope the soil is on), and the cover on the soil surface (i.e. plants or trees). Soil erodes and then replenishes naturally at a rate of only an inch or two per several hundred years.A problem only arises when soil erodes at an accelerated rate and cannot be replenished quickly enough. Accelerated erosion occurs when the energy from rain or wind contacts bare soil, detaching bits from the surface.

Topsoil is the upper, outermost layer of soil, usually the top 5 inches (13 cm) to 10 inches (25 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Topsoil is composed of mineral particles, organic matter, water, and air.It makes it so great.

Living organisms present in topsoil include archaea, bacteria, actinomycetes, fungi, algae, protozoa, and a wide variety of larger soil fauna, including springtails, mites, nematodes, earthworms, ants, insects that spend all or part of their life underground, and larger organisms such as burrowing rodents.

2.Cation exchange – process by which positively charged minerals are made available to a plant when hydrogen ions in the soil displace mineral ions from the clay particles. Roots cannot directly absorb cations from the soil. Cations are absorbed by root hairs along with H+. Most of the soil is negatively charged, therefore, when it rains, anions are leached in the groundwater, making it unavailable for uptake to roots.

Soil organic matter (SOM or just OM) has both positive and negative charges, so it can hold on to both cations and anions. Both the clay particles and the organic matter have negatively charged sites that attract and hold positively charged particles.

3.The hydrogen nucleus is made up of a particle carrying a unit positive electric charge, called a proton. The isolated hydrogen ion, represented by the symbol H+, is therefore customarily used to represent a proton. Because the bare nucleus can readily combine with other particles (electrons, atoms, and molecules), the isolated hydrogen ion can exist only in a nearly particle-free space (high vacuum) and in the gaseous state.

Most hydrogen is produced by heating natural gas with steam to form syngas (a mixture of hydrogen and carbon monoxide). The syngas is separated to give hydrogen. Hydrogen can also be produced by the electrolysis of water.

4.Biological availability, bioavailability, is a dynamic concept that considers physical, chemical, and biological processes of contaminant exposure and dose. ... Because bioavailability includes numerous processes, there have been many descriptions and interpretations, each focusing on different aspects.

5.During a rain storm,the negatively-charged nutrients get bio fixed in the atmosphere and reacts with oxygen to form dilute nitric acid.

6.Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils. Phosphorus is never readily soluble in the soil but is most available in soil with a pH range centered around 6.5.

If the soil is too acidic, it can be because of a calcium and magnesium deficiency, which is just as bad for plants as it is for humans. Iron and aluminum in great amounts can tie up phosphorus, which also makes the soil too acidic for plants.

7.Functions of Macronutrients and Micronutrients

Nitrogen: It is required by plants in large amounts. It is taken in the form of ions from the soil. It is required for the division of cells. It is the major constituent of proteins, vitamins, hormones etc.

Phosphorus: It is a constituent of cell membranes, proteins, and nucleic acids and is required for certain important reactions.

Potassium: It is a mineral that is required in the growing parts of the plants in large amounts. It is also required for the opening and closing of stomata. It helps in the activation of enzymes and helps in maintaining the turgidity of the cell.

Calcium: It is required during cell division and in the normal functioning of the cell membrane. Metabolic activities are also regulated by this mineral.

Magnesium: It is involved in the activation of enzymes in respiration and photosynthesis and helps in the synthesis of DNA and RNA. It is also an important constituent of ribosomes and helps in maintaining the structure of the ribosome.

Sulfur: It is an important constituent of amino acids, coenzymes, and vitamins.

Iron: It is required in larger amounts as compared to other micronutrients. It is an important constituent of protein and helps with the activation of enzymes.

Manganese: Enzymes involved in photosynthesis, respiration etc are activated by this. It helps in the splitting of water during photosynthesis.

Zinc and copper are also involved in the activation of certain enzymes. interstitial fluid helps in the uptake and utilization of calcium, functioning of the membrane, pollen germination, cell elongation, germination etc. Molybdenum is a component of certain enzymes like nitrogenase etc.

Chlorine: Chlorine helps in determining the solute concentration and the anion-cation balance of the cells.

Lack of nutrients can result in undernutrition, which can lead to deficiency syndromes (eg, kwashiorkor, pellagra). Excess intake of macronutrients can lead to obesity and related disorders; excess intake of micronutrients can be toxic.

8.Six of these nutrients are needed in large quantities. These six essential nutrients are nitrogen, phosphorus, potassium, magnesium, sulfur and calcium. The cool thing about them is that they help create new cells, which then organize into plant tissue. Without these nutrients, growth and survival would not occur.

9.No, younger parts of a plant more or less affected when mobile nutrition is in small quantity.

Calcium (Ca), sulfur (S), iron (Fe), boron (B) and copper (Cu) are immobile. If there is a deficiency of mobile nutrients, the symptoms are first seen in the older leaves, as the nutrients are transported to new growth from there.

10.Smart agriculture, also known as precision agriculture, allows farmers to maximize yields using minimal resources such as water, fertilizer, and seeds. By deploying sensors and mapping fields, farmers can begin to understand their crops at a micro scale, conserve resources, and reduce impacts on the environment.

11.Carnivorous plants typically live in wet habitats that are open and sunny, with nutrient-poor soils having an acidic pH . They do not like competition from other plants, and thus seem to thrive in the nutrient-poor habitats where other types of plants do not grow very well.

Pitcher plants have distinctive adaptations for living in nutrient-poor soils: These carnivorous plants produce a pitcher-shaped structure with a pool of water in it. When insects investigate, they slide into the pitcher and meet a watery demise. The plant then dissolves the insect and uses it for food.