Introduction to Agronomy

• Agronomy is the science and technology of producing and using plants for food, fuel, fiber, and land restoration.
• It encompasses work in the areas of plant genetics, plant physiology, meteorology, and soil science.
• Agronomy is the application of a combination of sciences.

Core Disciplines

• Soil science: Study of soil as a natural resource.
• Plant physiology: Study of plant function and behavior.
• Plant breeding: Science of changing the traits of plants in order to produce desired characteristics.
• Weed science: Study of weeds and their control.
• Entomology: Study of insects.
• Plant pathology: Study of plant diseases.

Soil Science

• Soil is a natural body consisting of solids, liquids, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following: horizons or layers that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.
• Soil science is the study of soil as a natural resource, including soil formation, classification, mapping, and physical, chemical, biological, and fertility properties of soils.

Plant Physiology

• Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants.
• It includes the study of all the internal activities of plants—those chemical and physical processes associated with life as they occur in plants.
• This includes study of photosynthesis, respiration, plant nutrition, plant hormones, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental physiology, and seed germination.

Plant Breeding

• Plant breeding is the science of changing the traits of plants in order to produce desired characteristics.
• Plant breeding has been practiced for thousands of years, since near the beginning of human civilization.
• It is practiced worldwide by amateurs such as gardeners and farmers, and by professional plant breeders employed by organizations such as universities, agricultural research centers, and seed companies.
• Plant breeding can be accomplished through many different techniques ranging from simply selecting plants with desirable characteristics for propagation, to more complex molecular techniques.

Weed Science

• A weed is a plant considered undesirable in a particular situation, "a plant in the wrong place".
• Weed science is the study of weeds and their control.
• Weed science involves understanding weed biology and ecology, and developing and implementing strategies to manage weeds in agricultural and non-agricultural settings.
• Key areas include weed identification, weed biology and ecology, and methods of weed control (chemical, cultural, biological, and mechanical).

Entomology

• Entomology is the scientific study of insects, a branch of zoology.
• Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes and one pair of antennae.
• They are among the most diverse group of animals on the planet, including more than a million described species and representing more than half of all known living organisms.
• Entomology includes the study of insect biology, behavior, ecology, classification, and management.

Plant Pathology

• Plant pathology is the scientific study of plant diseases caused by pathogens, environmental factors, and other agents.
• Plant pathology involves the study of plant pathogens, disease etiology, disease cycles, plant disease epidemiology, plant disease resistance, and plant disease management.
• Key areas include identifying plant diseases, understanding disease cycles, and developing strategies to manage plant diseases.

Agronomic Practices

• Crop rotation: Systematically varying the crops planted in a particular field.
• Tillage: Preparing land for cultivation.
• Irrigation and drainage: Artificially applying water to soil/removing excess water from soil.
• Fertilization: Supplying plants with essential mineral nutrients.
• Pest management: Managing insects, weeds, and diseases.

Crop Rotation

• Crop rotation is the practice of planting different crops sequentially on the same plot of land to improve soil health, optimize nutrients in the soil, and combat pest and weed pressure.
• A typical crop rotation might involve three or four different crops.
• Crop rotation can improve soil structure and fertility by alternating deep-rooted and shallow-rooted plants.

Tillage

• Tillage is the preparation of land for growing crops.
• It involves breaking up and turning over the soil, creating a seedbed, and controlling weeds.
• Conventional tillage involves plowing, harrowing, and other operations that disturb the soil.
• Conservation tillage practices minimize soil disturbance and leave crop residue on the soil surface.

Irrigation and Drainage

• Irrigation is the artificial application of water to the soil to supplement rainfall.
• Drainage is the removal of excess water from the soil.
• Irrigation and drainage are used to manage water availability for crops.
• Irrigation methods include surface irrigation, sprinkler irrigation, and drip irrigation.
• Drainage methods include surface drainage and subsurface drainage.

Fertilization

• Fertilization is the process of supplying plants with essential mineral nutrients.
• Plants require nutrients such as nitrogen, phosphorus, and potassium.
• Fertilizers can be organic (e.g., manure, compost) or inorganic (e.g., synthetic fertilizers).
• Fertilizer application rates and timing depend on the crop, soil, and environmental conditions.

Pest Management

• Pest management is the practice of controlling insects, weeds, and diseases that can damage crops.
• Pest management strategies include cultural practices, biological control, and chemical control.
• Integrated pest management (IPM) is a comprehensive approach that combines multiple strategies to minimize pest damage while minimizing environmental risks.
• IPM involves monitoring pest populations, using thresholds to guide treatment decisions, and selecting the most appropriate control methods.

Areas of Specialization in Agronomy

• Crop production: Focuses on maximizing yield and quality of crops.
• Soil management: Focuses on maintaining and improving soil health.
• Plant breeding and genetics: Focuses on developing new and improved crop varieties.
• Weed science: Focuses on controlling weeds in agricultural and non-agricultural settings.
• Precision agriculture: Involves using technology to optimize crop production practices.

Crop Production

• Crop production involves selecting appropriate crop varieties, managing plant populations, providing adequate nutrients and water, and controlling pests and diseases.
• Crop production practices vary depending on the crop, climate, and soil conditions.
• Key areas include crop selection, planting, fertilization, irrigation, and pest management.

Soil Management

• Soil management involves maintaining and improving soil health to support crop production.
• Soil management practices include crop rotation, tillage, cover cropping, and fertilization.
• Soil health is assessed by evaluating physical, chemical, and biological properties of the soil.
• Soil conservation practices are used to prevent soil erosion and degradation.

Plant Breeding and Genetics

• Plant breeding and genetics involves developing new and improved crop varieties with desirable traits, such as high yield, disease resistance, and drought tolerance.
• Plant breeding techniques include selection, hybridization, and genetic engineering.
• Plant breeders work to develop crop varieties that are adapted to specific environments and meet the needs of farmers and consumers.

Weed Science

• Weed science involves understanding weed biology and ecology and developing and implementing strategies to manage weeds in agricultural and non-agricultural settings.
• Weed management strategies include cultural practices, biological control, and chemical control.
• Weed scientists work to develop new and improved weed control methods that are effective and environmentally sound.

Precision Agriculture

• Precision agriculture involves using technology to optimize crop production practices.
• Precision agriculture technologies include GPS, sensors, drones, and data analytics.
• Precision agriculture practices include variable rate fertilization, precision irrigation, and targeted pest management.
• Precision agriculture aims to improve crop yields, reduce input costs, and minimize environmental impacts.