Exam 3 Flashcards
Sandy soils have a low water holding capacity and drain quickly.
True
A high VPD indicates reduced transpiration and less water stress on plants.
False
Any form of water, liquid or solid, falling from the atmosphere to the ground is called precipitation.
True
Waterlogging can lead to oxygen deficiency in roots and increase disease risk.
True
Saturation occurs when all the soil pores are filled with air.
False
RH is the percentage of water vapor relative to the air’s maximum holding capacity at a given temperature.
True
Excess precipitation can lead to waterlogging, while insufficient precipitation can cause drought stress.
True
Field capacity refers to the amount of water remaining in the soil after it has drained of excess water.
True
Either water-logging and drought stress can lead to poor yield.
True
High relative humidity (RH) increases plant transpiration rates.
False
Loam is the ideal soil type for horticulture due to its balanced properties.
True
The wilting point is the minimum soil moisture required for a plant to prevent wilting.
True
Low RH can lead to increased water loss from plants.
True
Precipitation includes only rain and snow.
False
Water is essential for plant growth and photosynthesis.
True
VPD represents the “pressure” that air puts on the plant to transpire and move air from the roots through the plant and out the stomata in their leaves.
True
Clay soils have a high water holding capacity but drain slowly.
True
Drought stress can cause reduced photosynthesis and wilting in plants.
True
Tomato production benefits from high VPD conditions during the summer.
False
Precipitation is the only factor that affects soil water content.
True
Thermal dissipation probes are used to measure sap flow in plant stems.
True
In Texas, tomato crops have a mid-season Kc value of approximately 1.15.
True
Water potential is the potential energy of water in a system.
True
The formula for calculating ETc is ETc = ETo ÷ Kc.
False
Drip irrigation is prone to clogging and requires regular maintenance.
True
Furrow irrigation is a type of surface irrigation.
True
Sap flow is constant in all plants, regardless of environmental conditions.
False
All irrigation systems are equally effective for every crop and soil type.
True
Evapotranspiration (ET) is the sum of evaporation and precipitation.
False
If the reference ET (ET0) for a location in Texas is 0.25 inches/day and the crop coefficient (Kc) for tomatoes at the mid-growth stage is 1.15, calculate the crop ET.
ET = 0.2875 inches/day
Cavitation only occurs in the xylem during extreme drought conditions.
True
Crop coefficient (Kc) changes depending on the crop’s growth stage.
True
Subsurface irrigation systems are the cheapest option for farmers.
False
In dry environments, plants close their stomata to conserve water.
True
Cavitation refers to the formation of air bubbles in xylem vessels, disrupting water flow.
True
Surface irrigation efficiency can reach up to 95%.
False
If the irrigation system efficiency is 80% and the tomato crop requires 8,146 gallons per day, how much water must be applied to meet the requirement?
10,182.5 gallons/day
Stomatal opening allows water to enter the leaf from the atmosphere.
False
Evaporation is water loss through plant stomata.
True
ET is critical for determining when and how much to irrigate.
True
The pressure potential in plant cells is always negative.
False
ET calculations require both environmental and crop-specific factors.
True
Water potential is a key factor in determining the direction of water movement in plants.
True
If the Kc for tomatoes is 0.4 in the initial stage and the ET0 is 0.2 inches/day, calculate the ET for this stage.
0.08 inches/day
Gravitational potential is the water potential due to the pull of gravity on water.
True
The pressure bomb (Scholander pressure chamber) measures leaf water potential.
True
Water potential is the measure of the potential energy of water in a system, determining the direction in which water will move.
True
Soil texture does not affect the efficiency of irrigation systems.
False
Advances in irrigation technology, such as AI, help predict water needs more accurately.
True
Sprinkler irrigation can be affected by wind, causing uneven distribution.
True
Soil water potential becomes less negative as water content decreases in soil.
False
Osmosis is the movement of water from an area of high solute concentration to low solute concentration.
True
Transpiration helps maintain turgor pressure in plant cells.
True
An irrigation system’s efficiency does not affect the total water applied to a field.
False
ET-based irrigation scheduling helps minimize water wastage.
True
Water moves through plants via cohesion and adhesion in xylem vessels.
True
During the peak water use period, the ET0 is 0.3 inches/day, and the Kc for tomatoes is 1.2. Calculate the daily ET.
0.36 inches/day
Stomata are involved in both gas exchange and water loss from the plant.
True
Xylem sap is composed of primarily water with dissolved minerals and nutrients.
True
Smart irrigation systems use IoT sensors to collect real-time ET data.
True
Liebig’s Law of the Minimum states that plant growth is determined by the most abundant nutrient.
False
Hydroponic systems are only suitable for growing leafy greens.
False
The USDA Soil Taxonomy classifies soils into 12 major orders.
True
Clay soils tend to retain moisture but may suffer from poor drainage.
True
Soil bulk density is higher in compacted soils.
True
Soils with high cation exchange capacity (CEC) hold fewer nutrients.
False
Deep Water Culture systems require plant roots to be submerged in a nutrient solution.
True
Clay soils tend to have a low CEC and poor water retention.
False
Loamy soil is generally considered the best for plant growth due to its balanced properties.
True
Soil horizons develop through processes such as weathering, leaching, and organic matter accumulation.
True
Soils with high porosity tend to have poor drainage.
True
Micropores are smaller than 0.000079 inches (0.008 mm) and hold water tightly.
True
Leafy greens like lettuce and spinach are well-suited for hydroponic cultivation.
True
Soil formation is primarily influenced by five factors: parent material, climate, organisms, topography, and time.
True
Hydroponics is a method of growing plants in soil with reduced water input.
False
Silty soils hold more moisture than sandy soils.
True
Aeroponics is a hydroponic system where plant roots grow in sand.
False
Sand particles are smaller than clay particles.
False
Soil texture is determined by the proportion of sand, silt, and clay.
True
Saline soils are beneficial for most crop plants.
False
Sandy soils are typically well-drained but have low nutrient-holding capacity.
True
Soil erosion is mainly caused by wind and water movement.
True
Soils with high cation exchange capacity (CEC) hold fewer nutrients.
False
Sandy soils have high nutrient-holding capacity.
False
Nitrogen (N) is essential for chlorophyll and amino acid synthesis.
True
Clay soils tend to have better drainage than sandy soils.
False
Climate has little impact on the rate of soil formation.
False
Drip hydroponics delivers nutrients through drip irrigation to plant roots.
True
Tomatoes, cucumbers, and peppers can all be grown hydroponically.
True
Phosphorus (P) is mainly responsible for regulating water balance in plants.
False
Vertical farming allows crops to be grown in multiple layers using artificial lighting.
True
Soil structure refers to the arrangement of soil particles into aggregates.
True
A soil with equal amounts of sand, silt, and clay is classified as sandy loam.
False
Silt particles are smaller than sand but larger than clay.
True
Parent material refers to the organic matter content in the topsoil layer.
False
Soil pH affects nutrient availability for plants.
True
Potassium (K) plays a key role in enzyme activation and water balance.
True
Alkaline soils (pH > 7.5) may limit the availability of iron and phosphorus.
True
Macropores allow for better air and water movement than micropores.
True
Calcium (Ca) is crucial for strengthening cell walls.
True
