These are non-living factors that influence the performance of a crop. Ex. Climate, weather, soil type, soil fertility, etc.

HORT 102: Climate and Weather Cultivated Plants: Lecture 18 [Teresa Koenig] Slide #: 1 Slide Title: Intro Information Slide Title: Lecture 15 Climate and Weather Speaker: Teresa Koenig Created by: Teresa Koenig, Kim Kidwell Music Slide #: 2 Slide Title: Slide 2 [Image daffodils in snow] [Image of dried out plant leaves] [Image of trees injured by ice] Plant Responses to Environmental Factors: Climate and Weather Over the next several lectures, we will be talking about some major environmental factors that affect plant growth. Slide #: 3 Slide Title: Two major types of factors affect crop production: Abiotic Biotic Two major types of factors that affect crop production are abiotic and biotic factors. Slide #: 4 Slide Title: Abiotic: are environmental factors. These are non-living factors that influence the performance of a crop. Ex. Climate, weather, soil type, soil fertility, etc. Abiotic factors are environmental factors such as climate, weather, soil type and soil fertility. They are non-living factors that influence the performance of a crop. Slide #: 5 Slide Title: Biotic: living things whose functions and/or activities affect the growth and development of a crop. Ex. Weeds, insects and disease

Biotic factors are living things whose functions and/or activities affect the growth and development of a crop. Examples of biotic factors are weeds, insects and diseases and we will spend some time on each of these various factors. Slide #: 6 Slide Title: Abiotic Factors Climate: The generalization of the weather conditions over years (i.e. what generally happens over the course of time). Describes long term status. The lectures that follow will look at the impact of abiotic factors on plant growth. This lecture will focus on climate. Climate is a generalization of the weather condition over years. It describes the long term status. So what generally happens over the course of time. Slide #: 7 Slide Title: Slide 7 Climate of an area is determined primarily by the input of sunlight which varies with latitude and time of year Follow the link in the Lessons Overview Page of this section for a short video on the geography of the seasons. The climate of an area is determined primarily by the input of sunlight which varies with latitude and time of year. Please follow the link the Lessons Overview Page of this section for a short video on the geography of the seasons. Slide #: 8 Slide Title: Microclimate: The environmental conditions immediately surrounding the plant. [Image of unevenly green grass field] In contrast to climate, the microclimate is the environmental conditions immediately surrounding the plant. A good example of that is a picture shown here on your slide where you can see the green grass where it has been watered appropriately and then the dry brown grass which has not received any water. So that is a good example of the microclimates in that particular yard or field of grass. Slide #: 9 Slide Title: Human activity can affect the microclimate surrounding a growing plant. Tillage, irrigation, soil drainage, ponds, other plants in the field, wind blocks, etc. alter temperature, moisture and humidity in the small area around the crop. Human activity can affect the microclimate surrounding a growing plant. Think of how tillage,

irrigation, soil drainage, ponds, other plants in the field, and wind blocks alter the temperature, moisture and humidity in the area immediately around the crop. These alterations are examples of changes in the plant s microclimate. Slide #: 10 Slide Title: Urban development can influence a plant s microclimate Buildings, blacktop or cement absorb heart form surrounding areas. Tall buildings can block air flow. Vegetation can cool the area around the plant via transpiration Urban development can also influence a plant s microclimate. Tall buildings can block air flow. Buildings, blacktop or cement absorb heart form surrounding areas warming the space around the plant. In contrast, vegetation can cool the area around the plant using transpiration. Slide #: 11 Slide Title: Weather: The temperature, wind direction, humidity, etc. at a given time (i.e. what is happening out there today). Describes short term status. Another term we should be familiar with is weather. Weather is the temperature, wind direction, humidity, etcetera at a given time. In other words, what is happening out there today? It describes a short term status of an area. Slide #: 12 Slide Title: Factors that determine crop distribution: 1. Precipitation 2. Temperature/growing season 3. Humidity Climate related factors that determine crop distribution are precipitation, temperature/ growing season and humidity. Slide #: 13 Slide Title: These factors determine the moisture availability and the level of heat and moisture stress crops are subjected to. These factors determine the moisture availability and the level of heat and moisture stress crops are subjected to. Slide #: 14 Slide Title: A. Precipitation Distribution: Cropping regions are classified on the basis of average annual precipitation.

Let s first look at the distribution of precipitation. Cropping regions are classified on the basis of average annual precipitation or rainfall. Slide #: 15 Slide Title: 1. Annual precipitation and cropping regions Annual ppc. (in inches) Cropping region Types of crops 0-10 Arid Grazing, desert vegetation 10-20 Semiarid Small grains 20-30 Subhumid Row and forage crops 30-40 Humid Forest, row & forage crops >40 Perhumid/Wet All crops This table shows the annual precipitation from 1 to over 40 inches per year and cropping regions for various types of crops. Pullman receives an average of 18 to 20 inches of rain per year so our area is a semiarid region where small grains such as wheat would thrive. Slide #: 16 Slide Title: 2. Monthly precipitation: Distribution of precipitation throughout the year is important in determining what crops can be grown where. The monthly distribution of precipitation throughout the year is important in determining what crops can be grown there as well. Slide #: 17 Slide Title: Slide 17 [Diagram of a graphic comparing annual precipitation at three locations] The average precipitation throughout the year is shown for three locations on this graph. Columbus, Ohio has the highest annual rainfall compared to the other two locations and this precipitation is pretty consistent throughout the year. The monthly distribution of rainfall for Lincoln, Nebraska and Pullman, Washington is basically reversed. Pullman gets more of its moisture in January and December while Lincoln receives its rainfall in mid-summer. Crops such as wheat and chick peas are perfected suited to the Pullman region because of this rainfall distribution. Slide #: 18 Slide Title: Precipitation that occurs during peak water use of the crop is the most beneficial. Precipitation that occurs during peak water use of the crop is going to be the most beneficial. Slide #: 19 Slide Title: Off-season precipitation is less useful unless it can be stored in the soil for future use.

Example: Summer-fallow: Keep field vegetation free for a growing season to store moisture. Off-season precipitation is less useful unless it can be stored in the soil for future use. One example is summer-fallow. Fallow means keeping field vegetation free for a growing season to store moisture. Slide #: 20 Slide Title: 1. Must remove weeds so that they don t deplete the water supply. 2. Only 25-30% of annual precipitation is stored. In this system, the weeds must also be removed so they don t deplete the water supply. Only 25 to 30 percent of the annual precipitation can be stored. Slide #: 21 Slide Title: Example: In a 12 rainfall zone, 15-16 of moisture will be available after a fallow year. For example, in a 12 inch rainfall zone, 15 to 16 inches of moisture will be available after a fallow year. Slide #: 22 Slide Title: Efficiency of water utilization is largely determined by the rate of transpiration from the plants plus the rate of evaporation from the soil. Summary equation_ Transpiration Evaporation = Evapotranspiration (ET) Efficiency of water utilization is largely determined by the rate of transpiration from the plants plus the rate of evaporation from the soil. This can be shown in the equation transpiration plus evaporation equals evapotranspiration or ET. Slide #: 23 Slide Title: ET is important for estimating the amount of water lost from a field and for predicting how much water needs to be replaced. Irrigation is based on ET. ET is important for estimating the amount of water lost from a field and for predicting how much water needs to be replaced. Crop irrigation is based on ET. Slide #: 24 Slide Title: Factors that effect ET:

a. Weather b. Crop type and growth stage c. Surface cover d. Availability of water in the soil Factors that affect evapotranspiration are weather, crop type and growth stage, surface cover and availability of water in the soil. Slide #: 25 Slide Title: a. Weather An example of a situation with large evaporative demands: High air temperature Low humidity Clear skies High wind Let s first look at weather. An example of a weather situation with large evaporative demands is a location with high air temperatures, low humidity, clear skies and high winds. Slide #: 26 Slide Title: b. Crop type Different crop species use different amounts of water Ex: Seasonal water use for: Corn: 23-28 /year Winter wheat: 16-18 /year Crop type different crop species and even varieties use different amounts of water. For example, seasonal water use for corn is 23 to 28 inches per year. Winter wheat only uses 16 to 18 inches per year. Slide #: 27 Slide Title: Crop growth stage Small plants transpire less than larger ones Maximum ET is just prior to reproductive growth stage At the reproductive stage and during seed/fruit maturity, ET decreases Crop growth stage small plants transpire less than larger plants. So maximum ET is just prior to the reproductive growth stage. At the reproductive stage and during fruit maturity, the evapotranspiration decreases. Slide #: 28 Slide Title: c. Surface cover

Lowest evaporation rates occur from shaded and mulched soil surfaces As crops grow, their canopy shades more of the soil; the canopy reduces evaporation from the soil The lowest evaporation rates occur from shaded and mulched soil surfaces. As crops grow, their canopy shades more of the soil and reduces evaporation from the soil. Slide #: 29 Slide Title: d. Availability of water in the soil. Evaporation is high in wet soil Rate of evaporation from the soil is low during dry periods Coarse, sandy textured soils have fast water filtration rates, therefore less water is left in the upper layers for evaporation. The final factor affecting ET is the availability of water in the soil. Evaporation is high in wet soil. The rate of evaporation from the soil is low during dry periods. Coarse, sandy textured soils have fast water filtration rates; therefore, less water is left in the upper layers for evaporation. Slide #: 30 Slide Title: B. Temperature: Intensity factor of heat energy. Source of heat on earth is the sun. Another important factor influencing crop distribution is temperature. Temperature is an intensity factor of heat energy. Our source of heat on earth is the sun. Slide #: 31 Slide Title: Temperature determines the length of the growing season. Annual growing season: the number of consecutive days without a killing frost measured from the last killing frost in the spring to the first killing frost in the fall. Temperature determines the length of the growing season. The annual growing season is the number of consecutive days without a killing frost measured from the last killing frost in the spring to the first killing frost in the fall. Slide #: 32 Slide Title: Crops vary in the number of days required to complete their life cycle. Increasing temperatures during growth typically decreases the number of days required to reach maturity. Crops vary in the number of days required to complete their life cycle. Increasing temperatures during growth typically decreases the number of days required to reach maturity.

Slide #: 33 Slide Title: Crop Growing Season Requirements Crop ~days required for life cycle Corn 120 Oats 90 Barley 80 Sugarcane 450 Cotton 180 So if we look at this table comparing different growing season requirements for various crops, sugarcane would require a much longer growing season, approximately 450 days to complete its lifecycle than something like barley which would require 80 days. You can relate this to areas where these crops are commonly grown such as the production of sugarcane in Brazil and the production of barley in the Dakotas. Slide #: 34 Slide Title: Base growth temperature (i.e. temp required for growth) for cool season crops like wheat and peas is 40 o F whereas the base growth temp. for warm season crops, such as corn and beans, is 50 o F. Ps will not occur until the base growth temperature is reached. The base growth temperature or the temperature required for growth for cool season crops like wheat and peas is 40 degrees Fahrenheit. The base growth temperature for warm season crops such as corn and beans is 50 degrees Fahrenheit. Photosynthesis will not occur until the base growth temperature is reached. Slide #: 35 Slide Title: Management: Based on average daily temperatures above the base growth temperature, crops can be managed to take advantage of the most optimal part of the growing season to maximize production. Based on average daily temperatures above the base growth temperature, crops can be managed to take advantage of the most optimal part of the growing season to maximize production. Slide #: 36 Slide Title: Example; Corn will go from seed to seed in 70-120 days. Depending on the growing conditions in each area, varieties are selected that will mature in the number of growing degree days (GDD) available in that area. For example, corn will go from seed to seed in 70 to 120 days. Depending on the growing conditions in each area, varieties are selected that will mature in the number of growing degree days available in that area.

Slide #: 37 Slide Title: Heat as measured by temperature regulates plant growth. GDD: used to determine the crop harvest (maturity) date based on heat units that accumulate over the growing season. Heat as measured by temperature regulates plant growth. Growing degree days are used to determine the crop harvest or maturity date based on heat units that accumulate over the growing season. Slide #: 38 Slide Title: 1. GDD accumulate in direct proportion to time in an optimal environment (which can only be created artificially in a growth chamber). 2. GDD can be used to time a plant s life stages. Growing degree days accumulate in direct proportion to time in an optimal environment. This could only be created artificially in a growth chamber. So growing degree days can be used to time a plant s life stages. Slide #: 39 Slide Title: Determining GGD number: 1. Determine the base growth temperature: 40 o F for cool season crops 50 o F for warm season crops How do we determine a growing degree day number? First, determine the base growth temperature of the crop. It is 40 degrees Fahrenheit for cool season crops and 50 degrees Fahrenheit for warm season crops. Slide #: 40 Slide Title: 2. Calculate the total heat units required to grow the crop from seeding through harvest. 4. Calculate the weekly or monthly sum of GDD (based on daily averages) to see when each growth stage will be reached. The next step is to calculate the total heat units required to growth the crop from seeding through harvest. Then, calculate the weekly or monthly sum of growing degree days based on daily averages to see when each growth stage will be reached. Slide #: 41 Slide Title: 4. Calculation method: a. Take the air temperature per day:

Max + Min 2 Values below freezing = 0. So, let s look at the calculation method for this. If we find the average air temperature per day, to do this, we take the maximum plus the minimum temperature divided by 2 and remember that temperature values below freezing, you would just use a 0 in this equation. Slide #: 42 Slide Title: b. Subtract the base temperature required for the plant of interest to grow. b. Add the GDD up for each day to determine how many heat units have been accumulated. Subtract the base temperature required for the plant of interest to grow. Then, add the growing degree days up for each day to determine how many heat units have been accumulated. Slide #: 43 Slide Title: Ex. Spring Wheat: requires from 2200-2400 GDD to go from seed to seed. Growth Stage Avg.# of GDD required Germination/emergence 75 Leaves to jointing 800 Jointing to pollination 1200 Head emergence 1500 Flowering and kernel formation 1650 Ripe grain is harvested 2400 For example, it takes spring wheat 76 growing degrees days to germinate, 1500 growing degree days for head emergence and 2200 to 2400 growing degree days to go from seed to seed. Slide #: 44 Slide Title: Example: Data to calculate GDD is obtained from the nearest weather station in the area. Can either get the maximum minus the minimum temperature for each day or they will provide you with a monthly summary. So, if you look at an example of a growing degree problem obtain the data to calculate the growing degree days from the nearest weather station in the area. You can either get the maximum minus the minimum temperature for each day or they will provide you with a monthly temperature summary. Slide #: 45 Slide Title: Example: Avg. Daily Temp (F) Location Feb March April May

Othello 38 45 50 55 Pullman 42 40 40 45 This shows the average daily temperature in Othello and Pullman for February, March, April and May. Slide #: 46 Slide Title: Can figure out when to plant a crop based on GDD. Planting date differs in different locations. So using this information, you can figure out when to plant a crop based on growing degree days. The planting dates differ by location. Slide #: 47 Slide Title: When should spring wheat be planted in these locations (base temp=40)? Avg. Daily Temp (F) Location Feb March April May Othello 38 45 50 55-40 -40-40 -40-2 5 10 15 Pullman 42 40 40 45-40 -40-40 -40 2 0 0 5 So based on the calculations, when should spring wheat be planted in these locations? The base temperature is 40 degrees Fahrenheit. So you would subtract the base temperature of 40 degrees from each of the average daily temperatures for each month. Slide #: 48 Slide Title: Therefore: Spring wheat can be planted earlier in Othello (Feb/March) than Pullman (April/May). Therefore, spring wheat can be planted earlier in Othello, so in February or March than Pullman, which would more realistically be April or May. Slide #: 49 Slide Title: With corn, base temp. is 50 o F, it couldn t be planted in Othello until April and Pullman until June. Corn has a base temperature of 50 degrees Fahrenheit. It cannot be planted in Othello until April and corn cannot be planted in Pullman until June. Slide #: 50 Slide Title: In reality, spring wheat is typically planted as early as possible in all growing regions.

Waiting until GDD are accumulating forces the crop to mature later and creates many agronomic difficulties. In reality though, spring wheat is typically planted as early as possible in all growing regions. Waiting until growing degree days are accumulated forces the crop to mature later and creates many agronomic difficulties. Slide #: 51 Slide Title: Slide 51 Unites States Department of Agriculture (USDA) has created a Plant Hardiness Zone Map to categorize plants based on the average annual minimum temperatures throughout the country Another way of determining plant selection based on temperatures is by using the United Stated Department of Agriculture or USDA Plant Hardiness Zone Map. This map categorizes plants based on the average annual minimum temperature throughout the country. Slide #: 52 Slide Title: Slide 52 The map categorizes locations for winter survival of a given plant in an average winter. A plant s survival depends on the temperature not falling below the minimum that it can tolerate. A plant s depends on the temperature not falling below the minimum that it can tolerate. So this map groups locations for a winter survival of a given plant in an average winter. Slide #: 53 Slide Title: Slide 53 [Image of USDA Plant Hardiness Zone Map from http://en.wikipedia/wiki/file:2012_usda_plant_hardiness_zone_map(usa).jpg] The average annual minimum temperatures are broken down by zone and are color coded on this Plant Hardiness Zone Map. Pullman is in USDA Hardiness Zone 5. See if you can locate that on the map. Slide #: 54 Slide Title: Slide 54 Seasonal variations can have detrimental effects on plants: Freezing in early spring or late fall Unusually high temperatures (heat stress) during the growing season [Image of daffodils under snow]

Variations such as freezing in early spring or late fall or unusually high temperatures during the growing season can have detrimental effects on plant growth and development. Slide #: 55 Slide Title: Controlling temperature effects on plant growth: 1. Good site selection: especially for permanent (perennials) crops. 2. Planting cold or heat tolerant crops However, there are ways we can control temperature effects on plant growth. The next four slides summarize some of these methods. Good site selection or planting crops where they are protected from wind or frost, especially for perennial crops or planting cold or heat tolerant crops can increase your chances of plant survival. Slide #: 56 Slide Title: Slid 56 3. Heaters and wind machines in orchards and vineyards 4. Forest, wind, blocks, vegetation, or water [Image of a wind machine] [Image of an orchard] Heaters and wind machines are commonly used in orchards and vineyards to prevent freeze damage to fruit. Forest, wind, blocks, vegetation and water can also help moderate temperatures. Slide #:57 Slide Title: Slide 57 5. Protective structures or coverings Ex: greenhouses, cold frames, row covers, high tunnels, mulches [Image of plastic covered structures in Guatemala] Protective structures or plastic coverings such as greenhouses, cold frames, row covers, high tunnels or plastic mulches are used to protect plants from freezing temperatures or extent the growing season of the crop either earlier or later. Slide #: 58 Slide Title: Air temperature ( o F) variations in high tunnels Pullman, WA Vancouver, WA Air temp Average Range Average Range Trial 1 Inside 37 4 to 89 46 25 to 68 Outside 33-7 to 68 42 25 to 76 Trial 2 Inside 40 27 to 71 46 40 to 57 Outside 34 18 to 65 44 34 to 55

Data courtesy of Kristy Ott-Borelli High tunnels look like small plastic greenhouses without heating or cooling systems. The numbers in this slide show the increase in air temperature inside the high tunnel structures compare the outside of the structures in two locations and these two locations are Pullman, Washington and Vancouver, Washington. So, if you look at the average inside temperature in Pullman, in trial 1 it is 37 degrees and outside it is 33 degrees. In Vancouver, the average outside temperature is 42 degrees and inside 46 degrees. When they repeated the trial, in Pullman, the average outside temperature 34 and inside was 40 degrees and in Vancouver, the average outside temperature was 44 degrees and inside was 46 degrees. And although those may seem like minor temperature increases compared to the outside air temperature, they would be enough to keep the crops from freezing and are used commercially for cool season crops such as lettuce. Slide #: 59 Slide Title: C. Humidity (Water content of the air): Amount of water a plant requires to grow normally is related to water content of the air. The final climate related factor determining crop distribution is humidity or the water content of the air. The amount of water a plant requires to grow normally is related to water content of the air. Slide #: 60 Slide Title: 1. If the air is moist, little evapotranspiration occurs so the plant requires less water. 2. If the air is dry, evapotranspiration occurs more rapidly and the plants require more water. If the air is moist, little evapotranspiration occurs so the plant requires less water. If the air is dry, evapotranspiration occurs more rapidly and the plants require more water.