Final Exam Study Guide AGRY/NRES 450 PDF

Final Exam Study Guide AGRY/NRES 450 Soil and Water Conservation Is it this study guide and the other one, or do we only need to know this stuff? A little of both o Tillage system o Erosion o Won’t...

Final Exam Study Guide AGRY/NRES 450 Soil and Water Conservation Is it this study guide and the other one, or do we only need to know this stuff? A little of both o Tillage system o Erosion o Won’t be small details from previous midterm o Test our knowledge of the things we have learned o Won’t be asking about the history of tillage o Principle and the application of principle Will see a lot about water quality o Like why one thing is working and the other one isn’t and how do they work o What are the principles guiding them Soil Health: the continued capacity to function in a way that continues to improve animal, human, and environmental health Worth 150 points Get 5 points extra for doing course evaluations Study the cycles and how those are integrated into conservation practices A lot of application question Define these principles and why they are effective and not effective There will be multiple choice 1. Define cropping system a. The cropping system refers to the crops and crop sequences and the management techniques used on a particular field over a period of years. b. Traditionally, they were designed for maximizing crop yield. However, in recent years with the increase in environmental issues that stem from row crop agriculture, there is a stronger demand for cropping systems. 2. Explain the different types of cropping systems a. When looking at the components of cropping systems, we must look at all the different tillage systems and residue management practices such as No-till, Chisel tillage, etc. Then we must look at the specific cropping system that would work best with the tillage system implemented based on varying components such as topography, climate, and soil resilience. After we need to look at the nutrient and water management practices that would be most beneficial such as precision farming, irrigation/drainage practices, and water harvesting. Last we would need to look at what erosion control practices 1  would be best implemented such as conservation buffers, windbreaks, and terraces. b. Types of Cropping systems: i. Fallows systems ii. Monoculture: refers to a cropping system where the same crop is grown in the same field on a continuous basis 1. The most common cropping system throughout the world is efficient in planting and harvesting and is driven by the economy and population growth 2. It seems to be more common to do this with corn than with soybeans 3. Disadvantages: a. Eliminates crop diversity b. Degrades soil structure c. Reduces biological diversity d. Increases use of inorganic fertilizers and pesticides e. Decreases crop yields f. Increases soil‘s susceptibility to erosion, weed invasion, and pest incidence g. Decreases soil resilience h. Decreases wildlife habitat 4. Advantages a. Allows specialization in a specific crop b. Favors large-scale farm/modern operations c. Generates a large volume of specific farm products and often produces higher profits d. Reduces the cost of farm equipment e. Makes seed preparation, planting, and harvesting relatively easy f. Reduces cultural operations g. Narrows harvesting times h. Increases profit due to economy of scale iii. Double Cropping: consists of planting crops following harvest of the first on the same land during the same year 1. Produces two products on the same land within the same year 2. If the growing environment is conducive, greater profit could come from harvesting twice in one year 3. Double cropping tends to be more conducive in the more southern half of Indiana with mixed results in the other areas of Indiana. The primary reason for this is the number of days from emergences to maturation of the crops prior to a freeze is lower since the southern areas tend to experience the first fall freeze further out in the year. The other major factos is that double crop soybean success is primarily successful when paired with 2  sufficient soil moisture especially during the establishment of the crops. iv. Contour cropping: Planting or tilling following the contour lines of a field 1. A contrast to up/down slope farming 2. Creates furrows and crops rows perpendicular to the slope 3. Reduces water and wind erosion in soil with slopes up to 10% v. Strip Cropping: Like contour farming strip cropping rows are established on contour lines 1. Strip cropping alternate strips of row crops within the same field 2. It’s giving a Dr. Suess movie scene vi. Crop rotations: This is a cropping system that rotates different crops sequentially on the same field in alternating years 1. There are 3 characterizations of crop rotations: a. Monoculture: confined to a single crop with no diversity b. Short rotation: It is basically a 2-yr rotation (eg. Corn- soybean) c. Extended Rotation: It refers to >2-yr rotations (eg. Corn-oat-wheat-clover-timothy) 2. Advantages: a. Reduces soil erosion b. Improves soil properties c. Increases organic matter content d. Improves soil fertility e. Increases crop yield f. Reduces build-up of pests g. Increases in net profits h. Improves wildlife habitats i. Reduces use of chemicals j. Reduces water pollution vii. Cover crops viii. Mixed and relay cropping: the cropping of interseeding the second crop into the first crop before harvest 1. Water availability is the main determinate of relay and double cropping ix. Organic farming: This includes no-till, residue mulch, integrated nutrient management, and cover cropping x. Intercropping cropping: growing multiple crops simultaneously in the same field 1. Very common in vegetable and fruit production and the organic farming industry 3. Trends for Indiana due to Climate Change a. Earlier spring soil warm-up and Later arrival of First Autumn Freeze. This means that the soil will be subjected to a lot of changes such as increased soil 3  saturation early in the growing season. Along with this there will be reduced plant-available water due to longer periods between rain events coupled with an increased water demand due to the higher temperatures that will increase rates of evaporation. b. Corn yield in Indiana is expected to decrease across all areas of the state in irrigated and non-irrigated fields. 4. Define Soil Health a. Soil Health is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. b. Not the same thing as soil quality since soil quality is defined by functionality (Ecosystem services) in productivity. In other words, it relates to the physical and chemical properties of the soil whereas soil health relates to the biological and ecological characteristics. Denitrification: a process where bacteria convert plant-available soil nitrate into nitrogen gases that are lost from the soil. o Normally in aerated soil, bacteria break down organic matter in the presence of oxygen to produce carbon dioxide, water and energy. However, in very wet or waterlogged soils, all the pore space is filled with water so the oxygen is rapidly depleted causing bacteria to use nitrate instead of oxygen for respiration. o The conditions for denitrification to occur are low oxygen availability through poor drainage and water logged conditions, substrate availability from high organic matter, temperatures greater than 59 degrees Fahrenheit, nitrate availability for denitrification, acidic soil pH o The nitrogen gases released during denitrification: nitric oxide (NO), nitrous oxide (N2O), and di-nitrogen (N2) c. Organic matter is considered the Master variable of Soil health i. Improves water holding capacity of soils (physical, biological) ii. Improves soil structure (physical) iii. Improves soil strength (physical) iv. Food source for soil microbes (biological) v. Provides CEC (chemical) vi. Contains nutrients, especially nitrogen (chemical) vii. Is the solution for short- and long-term management d. Healthy soil gives us clean air and water, bountiful crops and forests, productive grazing lands, diverse wildlife, and beautiful landscapes. Soil does this by performing 5 essential functions. 4  i. Regulating Water: helps control where rain, snowmelt, and irrigation water go. Water flows over the land or into and through the soil. ii. Sustaining plant and animal life: The diversity and productivity of living things depends on soil. iii. Filtering and buffering potential pollutants: The minerals and microbes in soil are responsible for filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric deposits iv. Cycling nutrients: carbon, nitrogen, phosphorus, and many other nutrients are stored, transformed, and cycled in the soil v. Providing physical stability and support: soil structure provides a medium for plant roots. Soils also provide support for human structures and protection for archeological treasures. e. Physical attributes: i. Aggregation and structure: a measure of how well soil aggregates resists disintegration when hit by rain drops ii. Surface sealing iii. Compaction iv. Porosity v. Surface Hardness: a measure of the maximum soil surface penetration resistance between 0-6 in deep using a field penetrometer vi. Subsurface Hardness: a measure of the maximum resistance encountered in the soil between 6-18 inch depths using a field penetrometer vii. Available Water Capacity: reflects the quantity of water that a distributed sample of soil can store for place use. It is the difference between water stored at field capacity and at the wilting point. f. Biological attributes: i. Macrofauna ii. Microfauna iii. Micro organisms iv. Roots Pathogen Pressure Rating: measure of the degree to which sensitive test-plant roots show symptoms of disease when grown in standardized conditions in assayed soil v. Soil Protein: measure of the fraction of the soil organic matter which contains much of the organically bound N vi. Soil Respiration: measure of the metabolic activity of the soil microbial community 5  vii. Active Carbon: a measure of the small portion of the organic matter that can serve as an easily available food source for soil microbes, thus helping fuel and maintain a healthy soil food web viii. Biological activity ix. Organic matter g. Chemical attributes i. pH ii. salinity: a measure of the soluble salt concentration in soil, and is measured via electrical conductivity iii. Sodicity: a calculation of the sodium absorption ratio and is measured using ICP spectrometry to determine Na+, Ca2+, and Mg2+ concentrations iv. Nutrient Holding Capacity v. nutrient availability vi. Heavy Metals: is a measure of levels of metals of that could pose a possible concern to human or plant health. They are measured by digesting the soil with concentrated acid at high temperatures. h. Overall Quality Score: At the bottom of the report is an average of all the ratings and provides an indication of the soil’s overall health status. The colors associated with each functionality ranging from red to dark green will be averaged out, to identify the overall health status. The main objective of this score is to understand which conservation practices yielded the score and what should be repeated and changed depending on the end result. i. Haney Soil Health Test: measures the soil nitrogen-total N and inorganic N, Solvita 1-day CO2-C, water extractable organic Carbon and nitrogen (C:N ratio) i. Lower amounts with the Haney Test would trigger a higher nitrogen application rate than when using a standard testing procedure and U of MN fertility guidelines 5. Define Soil Resilience a. Soil Resilience: refers to the intrinsic ability of a soil to recover from degradation and return to a new equilibrium similar to the antecedent state or to resist change due to disturbance i. The ability of a soil ecosystem to return to dynamic equilibrium after disturbance ii. The ability of the soil to resist or recover from an anthropogenic or natural perturbation iii. The ability of the system to revert to its original or near original level performance or state that existed before the impressed forces altered it iv. Processes that enable soils to counteract stress and alterations v. The capacity of the soil to resist change caused by a disturbance 6  vi. The ability of a system to recover its “functional and structural integrity” after a disturbance vii. Functional Integrity: 1. Fate and decay of organic compounds 2. Microbial activity 3. Immobilization and transformation of chemicals 4. Recycling of nutrients viii. Structural Integrity 1. Soil aggregation 2. Porosity 3. Air and water flow 4. Drainage b. How do you know that soil is resilient? i. Highly Resilient: Rapid recovery, high buffering 1. Response to soil erosion: highly resistant or non-erodible 2. Soil Characteristics: Very deep and very high organic matter content, aggregate stability, and water infiltration rates with profile depth ii. Resilient: recovery with improved management 1. Response to soil erosion: Resistant or very slightly erodible 2. Soil Characteristics: deep and high organic matter content, aggregate stability, and water infiltration rates with profile depth iii. Moderately Resilient: Slow recovery with high input 1. Response to soil erosion: moderately resistance or erodible 2. Soil characteristics: moderately deep and moderately high organic matter content, aggregate stability, and water infiltration rates iv. Slightly Resilient: slow recovery even with change in land use 1. Response to soil erosion: low resistance and highly erodible 2. Soil Characteristics: shallow soils and low organic matter content, aggregate stability, and water infiltration rates v. Non-Resilient: No recovery even with change in land use 1. Response to soil erosion: non-resistant or extremely erodible 2. Soil Characteristics: very shallow and very low organic matter content, aggregate stability, and water infiltration rates 6. List and understand the factors that affect soil resilience Factors a. Parent material: determines soil texture i. Controls: 1. Water, air, and heat fluxes 2. Translocation of fine soil particles 3. Eluviation and illuviation 4. Water storage, pore space, and pore morphology 5. Erodibility 7  6. Clay content impact’s structure and infiltration b. Topography: impact of soil slope i. Erodibility ii. Water movement and transport of soluble salts iii. High slopes: spares vegetation and reduced plant diversity 1. Impact plant rooting depth iv. Low slopes: high plant population and diversity, lower bulk density, greater soil holding capacity and moisture c. Time: Changes in infiltration (12,22,60,100-fold increase in 1,2,3, and 4 years) and soil carbon (10-20 years after reclamation begins) d. Climate: precipitation, temperature, humidity, and evaporation influence the magnitude of soil resilience i. Rainwater: infiltrates the soil and carries fine soil particles and dissolved substances and contributes to soil formation and restoration ii. Temperature: moderate plant growth and microbial processes e. Organisms f. Biota: Flora and Fauna i. Flora: vegetative cover protects the soil surface. Plant roots create a network of channels and fine pores that facilitate soil forming processes 1. plant roots also add soil carbon and enhance soil structure and aggregate stability ii. Fauna: facilitate nutrient turnover and cycling, soil organic matter turnover, soil aggregation, and chemical transformations and solubilization Processes that affect soil resilience g. Physical i. Physical weathering ii. Soil, water, are, and heat fluxes iii. Macro-and-micro aggregation iv. Flocculation v. Shrinking and swelling vi. Clay formation h. Chemical i. Weathering ii. Immobilization iii. Transformation iv. Nutrient cycling v. Buffering capacity vi. C sequestration i. Biological i. Biological weathering ii. Root growth iii. Activity of macro-and micro-organisms iv. Soil organic matter decomposition and accumulation 8  v. Biodegradation and biotransformation 7. Be able to examine a soil profile and classify its resilience a. Be able to define each category of resiliency without looking at the study guide. Will be given a visual and be asking 8. The history of soil drainage Commented [Ek1]: Focused more on the principles, so a. “Act in 1816”: The first mention of drainage in Indiana statute which provided there won’t be really any history on the final. Maybe one history question the Highway supervisor the ability to drain roads. i. Allowed them to enter lands of others when necessary, without being considered trespassing, to open ditches in efforts to drain roads and fields b. “Act of 1832”: this act provided lands within Tippecanoe, Montgomery, Clinton, and Warren counties the ability to drain swamps, ponds, marshes, and other lowlands. c. “1861 Act”: provided landowners the right to enter upon land of others in order to deepen or maintain any natural channel, required to drain their land d. “Between 1860 and 1890”: new acres were constantly being put to the plow as forests were cleared and swamps were drained. The acreage of tillable land in the state almost doubled in the two decades after the Civil War. Towns and cities also sprang up or increased in size thanks in part to the Drainage Laws and the infrastructure they helped provide 9. Define soil water potential and understand its impact on soil drainage a. How to enhance Soil drainage: i. Subsurface drainage systems have a purpose of removing groundwater from within the soil and to subsequently lower the water table ii. They require channels to catch the excess water flow iii. Internal drainage: when the pathway for drainage is located below the level of the water table. 1. Deep Open-Ditch Drainage 2. Buried Perforated Pipes 3. Building Foundation Drains b. Soil water potential: controls a soils ability to facilitate runoff depends on its antecedent soil water content i. Gravitational Potential: this is the force that pushes the water to the center of the earth ii. Matric Potential: this is the pressure that is exerted from the attraction of water to solid surfaces 1. Influenced by cohesion and adhesion of water iii. Osmotic Potential: Pressure derived from the presence of both inorganic and organic solute in the soil solution 9  1. The higher up in the soil profile, the lower the osmotic potential iv. Hydrostatic Potential: pressure exerted by a fluid at equilibrium due to the forces of gravity 1. Only applies to water that is below the water table aka saturated water 2. Greater the further down the soil profile c. Properties of Water: i. Its structure is asymmetrical, V-shaped at 105 degrees ii. Water exhibits polarity with there being an electropositive attraction near hydrogen and an electronegative attraction near the oxygen iii. Hydrogen bonding iv. Cohesion: water molecules attracted to another water molecule v. Adhesion/Adsorption: when a water molecule is attracted to a solid surface 1. Clay loam has smaller pores tend to produce greater adhesive forces and the direction in which it moves up is the capillary flow and is increased due to adhesion vi. Capillary Flow: Water moves up hill (or truly in any direction) due to the forces of adhesion and cohesion 1. Greatest to lowest capillary rise: Clay Loam, Loamy Sand, Sand d. U.S. Tile Drainage Density i. Highest density is in Iowa, Illinois, Indiana, and Michigan e. Surface runoff occurs before discharge i. In northeastern Indiana, peak tile discharge occurred often concurrent with or even shortly before peak discharge in surface runoff ii. Surface water seems to rapidly percolate through the soil to the tile, thus, peak discharge in tile occurs at approximately the same time as surface runoff 10. Define hypoxia and key factors that contribute to hypoxia in the Gulf of Mexico Commented [Ek2]: What are the essential things that a. The total Nitrogen and phosphorus is the greatest in the Midwest region of the need to be present for it to be considered hypoxia Oxygen concentration distribution across the gulf of Mexico US and what is the impact of that and how to connect that to b. Hypoxia: when there is low oxygen present in the water and is primarily a farming practices. Like how the nutrient runoff effects the problem for estuaries (where rivers meet the sea) and coastal waters water there and algal blooms need to be mentioned i. Hypoxia waters have dissolved oxygen concentration of less than 2-3 regarding how it affects oxygen concentration. How will nutrient runoff effect precipitation. ppm ii. Can be caused by excess nutrients, primarily nitrogen and phosphorus iii. The excess of nutrients and eutrophication promotes algal growth 1. As the dead algae decomposes, oxygen is consumed in the process, creating lower levels of oxygen in the water iv. The process of Hypoxia: 1. Nutrient-rich water flows in 2. Algae grow, feed, and die 10  3. Zooplankton eat algae 4. Bacteria feed on fecal pellets and dead algae 5. Bacteria deplete the water of oxygen 6. Marine Life flees or dies v. There are 400 hypoxic zones in the world and the one in the Gulf of Mexica is the largest in the United stated and one of the largest globally vi. Evidence of hypoxia was first documented in 1972-1974 during a cruise survey of oxygen levels where the depths were found to be 10- 20 meters at various points throughout the gulf 1. The process of artificial fixation of nitrogen began in 1913, but it didn’t exceed natural nitrogen fixation rates until 1970 a. Artificial fixation of Nitrogen: any natural or industrial process that causes free nitrogen (N2), which is a relatively inert gas plentiful in air, to combine chemically with other elements to form more-reactive nitrogen compounds such as ammonia, nitrates, or nitrites. 2. The runoff of nitrogen into the Mississippi River increased after 1970 after being washed into the Gulf of Mexico, the nitrogen resulted in eutrophication and anoxia of the bottom waters vii. This years dead zone is the biggest one ever measured covering 8,776 square miles 1. Its adding fuel to a debate over whether state and federal governments are doing enough to cut pollution that comes from farms viii. Farmers use those nutrients on fields as fertilizer, but then the rain washes them into nearby streams and rivers that eventually reach the Gulf of Mexico. ix. These hypoxic conditions have been existed in the Gulf Of Mexico since the 1950s c. Nutrient Reduction Strategy: purpose is to develop nutrient reduction strategies based on voluntary implementation while continuing to develop numeric nutrient standards i. GOAL: load reduction of 45% in total nitrogen and total phosphorus losses leaving each state by 2035 ii. INTERIUM GOAL: load reduction of 15% NO3-N and 25% Phosphorus by 2025 11. Understand the N and P cycles. Be able to describe in detail the inputs, transformations, and losses. (be able to draw it out and describe each part) Commented [Ek3]: Be able to draw these out by the final a. Science Assessment of Nutrient Loading: i. Total Nitrogen: 82% of its runoff comes from agriculture and the rest is from a point source ii. Nitrate-N: 80% comes from agriculture and the rest is from a point source 11  iii. Total Phosphorus: 48% comes from agriculture and then 48% comes from a Point source b. c. N cycle: 12  d. P cycle: 12. Be able to list infield and edge of field nutrient lost reduction strategies and explain the scientific principles by which they function. a. Infield nutrient loss reduction strategies: i. Reducing nitrogen rate from background to MRTN on 10% of acres ii. Nitrification inhibitor with all fall-applied fertilizer on tile-drained corn acres iii. Split application of 50% fall and 50% spring on tile-drained corn acres iv. Spring-only application on tile-drained corn acres v. Split application of 40% fall, 10% pre-plant, and 50% percent side dress vi. 1.8 million acres of conventional till eroding > T converted to reduced, mulch, or no-till vii. No fall nitrogen application viii. Phosphorus rate reduction on fields with soil test Phosphorus above the recommended maintenance level ix. Cover crops on 1.6 million acres eroding > T currently in reduced, mulch, or no-till x. Cover crops on all corn/soybean tile-drained acres 13  xi. Cover crops on all corn-soybean non-tilled acres b. Edge of field nutrient loss reduction strategies: i. Bioreactors on 50% of all tile drained land ii. Wetlands on 35% of tile-drained land iii. Buffers on all applicable crop land (reduction only for water that interacts with active area) c. Drainage Water Management (controlled drainage) i. Raise outlet after harvest ii. Lower outlet prior to spring in late march iii. Raise temporarily after field work is complete (to store water) and lower as plant roots grow deeper d. Reduced Drainage Intensity i. Reduction in tile drainage depth from 36-60 inches to 30-42 inches ii. Shallow drainage decreases the drainage iii. Decreases the transport of nitrate iv. Could possibly increase surface runoff e. Bioreactors i. Trenches filled with a carbon source, commonly woodchips. ii. The woodchips act as a medium for microbial activity and serve as a carbon source to drive the denitrification process. iii. Nitrate-laden water flows through the woodchip-filled trench, where anaerobic conditions encourage denitrifying bacteria iv. Denitrifying bacteria use the carbon from the woodchips and nitrate as an electron acceptor, converting nitrate (NO₃⁻) to nitrogen gas (N₂), which is harmless and released into the atmosphere v. The effectiveness of a bioreactor depends on factors such as water retention time, temperature, nitrate concentration, and carbon source quality. vi. Average 30-40% nitrate load reduction vii. Design life: estimated 10-15 years viii. Required no land to be removed from production 13. Be able to contrast the fate of nitrate and phosphate. a. Fate means when it leaves the soil or how a plant can get either nutrient or how that affects the rate of loss. And how those effects management practices that control them. b. Phosphate is more immobile in contrast to nitrate c. Between 25-80% of the Phosphorus lost from the fields monitored in the St. Joseph River watershed was observed to occur from the subsurface tile in these fields i. These findings suggest that to reduce phosphorus loading to reach targets set for Lake Erie, we must not only manage fields to reduce surface runoff phosphorus losses, but also manage for phosphorus transport to tile d. Cover crops i. reduce the effect of runoff by 16% 14  ii. reduce sediment loss by more than 50% iii. reduce total phosphorus loss by more than 50% iv. reduced the dissolved phosphorus loss by 60% for broadcast fertilizer e. Impact of long-term Cover Crop Management on DRP (dissolved reactive Phosphorus) i. The greatest phosphorus release was from 0-2 cm depth ii. Radish/Oats>CR>AR at the 0-2cm depth f. Two-stage ditch: developed by observing the natural processes of stable streams and rivers that could relieve the erosion, scouring and flooding that a conventional ditch may cause i. Design strategy: 1. A channel that is sized to convey an effective discharge system 2. A bench to serve as a floodplain for the smaller channels 3. A stage of adequate width to prevent flow overtopping the ditch banks and flooding surrounding land ii. The result is a drainage system that can benefit both agriculture and the environment iii. Enhances nitrogen removal capacity and reduce turbidity and dissolved phosphorus in agricultural streams iv. Issue it is solving: drainage has been an important issue in agriculture for years and stream channels have been highly modified to a trapezoidal shape designed to transport the flow from large storm events to drain extensive portions of our productive agricultural land. The ditch is often oversized for small flows and provides no floodplain for large slows. 15