Environmental Factors of Plant Production Ag. 514

Five Requirements for Plant Growth Sunlight Temperature Moisture Air Nutrients

Most Important Requirement for Plant Growth and Survival Water Conducts nutrients Cell composition Structure/turgidity

Most Important Factor Affecting the Adaptation of Plants to a Region Temperature Temperature varies with: Latitude Altitude Topography.

Temperature is created by heat energy, in the form of solar radiation.

Latitude Latitude –how far north or south further north = less sun Further south = more sun

Altitude/Topography Topography The lay of the land South- and south-western facing slopes receive more solar radiation. Higher altitudes and northern latitudes are associated with colder temperatures

The Palouse

Seasonal fluctuations in temperature influence growth by determining the optimum length of growing conditions for a plant species.

Surface temperature / varying factors Heat transfer from the surface as it warms from the morning sun to the atmosphere, as it cools at night. Plant growth is greater at night, when temperatures cool.

Plant adaptation to cold temperatures is known as a plant’s hardiness Plant adaptation to cold temperatures is known as a plant’s hardiness. Tender plants cannot tolerate extremes in cold temperatures.

Evaporation Water changes from a liquid to a gaseous state.

Micro and Macro Environments The macroenvironment The atmosphere surrounding a plant. The microenvironment The area at ground level immediately surrounding a plant; the plants “personal” space Microenvironments can be manipulated to support plant growth.

The Three Areas of the Plant Environment Atmospheric Related to the air Edaphic Related to the soil Biotic Related to the organisms’ living in the soil

Atmospheric Environment Includes the macroenvironment of the plant. Can include simulated plant environment (e.g., greenhouse) or natural plant environment. Atmospheric conditions include: Temperature Moisture Light Wind.

Atmospheric Environment (Cont’d.) Weather systems tend to be regionally consistent, and play a large role in plant adaptation. How does the weather in Meridian compare with the weather in Honolulu?

Weather Comparisons Meridian Honolulu Record high 105 Record low -26 Average high 68 Average low 38 Total rain fall 9.94 Honolulu Record high 95 Record low 52 Average high 85 Average low 70 Total rain fall 18.3

Atmospheric Environment (Cont’d.) Cycles of day and night effect plant growth, exhibited by comparing plant growth at different latitudes. Temperature is affected by latitudinal distance from the equator.

Plants receiving both types of rays exhibit normal growth. How much light and the type of light a plant receives affects its growth cycle. Angular rays of morning promote cellular elongation. Perpendicular rays of midday promote cellular stunting. Plants receiving both types of rays exhibit normal growth. Direct sun causes compact growth. Shading creates longer, taller plants.

Atmospheric Environment (Cont’d.) Water Protoplasm in plant cells is primarily water. Water uptake increases cell turgidity. Turgor pressure = force exerted outward on the plant cell wall Water is essential to increase plant hardiness in hot weather.

Atmospheric Environment (Cont’d.) Water vapor Transpiration (absorption, transport, and release of water to the atmosphere) cools leaves. Evapotranspiration (ET) is the rate of transpiration as affected by the rate of evaporation. The ET rate is used because it is difficult to distinguish where water vapor is coming from - soil evaporation or plant transpiration.

Atmospneric Environment (Cont’d.) Moisture availability to plants Precipitation (rain and snow) Water vapor (relative humidity) Dew (condensation - when air temperature is warmer than surfaces) Wind / air movement Velocity is the key factor. Breezes cool a plant in hot weather. Wind kills plants in hot weather Storms can damage or destroy plants.

Edaphic Environment Soil environment surrounding the plant. Soil horizons Soil particle structure Soil organic matter Water movement through the soil Percolation (from surface into soil structure) Capillary (wicking action upward) Gravitational (downward flow)

Edaphic Environment (Cont’d.) Aeration Air into and through soil Upward and out of soil Temperature Soil warmth is essential for seed germination. pH Soil acidity or alkalinity creates conditions for plant adaptation and growth. Salinity Soil salinity (salt in the soil) creates conditions for plant adaptation and growth. Plants vary in their tolerability to saline conditions.

Edaphic Environment (Cont’d) Biomass Source of organic matter in soil. Living (standing crop matter and living organisms). Non-living (decomposing and decomposed (humus) vegetative and animal matter). A healthy soil has a diverse biomass for its source. Competition for water, space, and light is balanced between plants. Competition between organisms is balanced within the soil, allowing plant roots to receive essential nitrogen.

Biotic Environment Biotic and Abiotic Environment Biotic: living components of the biosphere. Abiotic: non-living (physical and chemical) components of the biosphere.

Biotic factor: the influence of organisms upon other organisms (i. e Biotic factor: the influence of organisms upon other organisms (i.e., shading, competition, symbiosis, commensalism, parasitism). Includes man’s influence on plant life by cultural practices, or by creating damaging conditions for plants.

Negative influences: Positive influences: Soil compaction compression of soil, reducing availability of water and air; limits root growth. Wear Loss of vegetation due to excess traffic through an area (i.e., a worn path through a lawn). Wasteful pesticide management Over-fertilization Wasteful irrigation practices. Positive influences: Selection of adaptive plant species for use in the landscape. Limited cultural practices on plants (limited to the basics).

Best strategy is to incorporate best management practices in plant culture: Selective pruning Selective fertilization and irrigation Composting Mulching Soil aeration Integrated pest management Controlled impact zones (minimize compaction and wear).

Record-keeping in plant culture - a best management practice. Successful record-keeping includes: Deciding what data needs to be recorded The most useful system of recording the data Easy access to the recorded information. Records should correspond with container labels.

Crop records should include five basic elements of plant culture In each batch: Variety and propagation date (seeds or cuttings) Number of seeds / cuttings sown Number of transplants / date Ready-for-plant date Cultural procedures used for the particular plant variety, including containers used (germination, transplant, and sale containers, if different).

Good record keeping is essential to good science. Recording allows the prediction of outcomes and the anticipation of possible problems (unexpected variables). Good records lead to problem resolution based on facts (occurrences). Facts are generalizable to similar situations, making their application useful to predict similar outcomes (increasing dependability of results