Crop Science 2

• Agriculture is the systematic raising of useful plants and livestock under the management of man
• Agriculture is the purposeful work through which the elements of nature are harnessed to produce plants and animals to meet human needs
• Agriculture is the broad industry engaged in the production of plants and animals for food and fiber, the provision for agricultural supplies and services, and the processing, marketing and distribution of agricultural products
• Pastoral Age (Hunting/Gathering):

  • Primitive man satisfied his daily needs directly from nature by hunting wild animals, gathering wild plants and fishing
  • The hunter-gatherers moved from one location to another in search of food to sustain them
  • The fishing tribes were more likely settled in one place as a permanent home usually near bodies of water
• Beginnings of Agriculture:

  • The gradual transition from hunting-gathering to agriculture began about 10,000 - 15,000 years ago
• Agriculture started simultaneously in various parts of the world
• The world population is expected to increase to 9.1 B by year 2050 from 7.0 B today

  • Increase in world population leads to increased pressure in agricultural lands
  • It is imperative to increase current levels of food production to provide an adequate supply of food to the increasing population
• Definition and scope of Crop Science:

  • Science is systematically accumulated and tested knowledge
  • Crop Science is concerned with the observation and classification of knowledge concerning economically cultivated crops and the establishment of verifiable principles regarding their growth and development for the purpose of deriving the optimum benefit from them
  • Crop Science is divided into two areas: Agronomy and Horticulture
• Carolus Linnaeus was the first originator of the binomial system of plant nomenclature

  • Family names in plants have the first letter capitalized and end with -aceae attached to the Genus name
  • Scientific names have the first letter of the Genus name capitalized, while the species name is in small letters and are either italicized or underlined
• Crops are classified in several ways in Crop Science:

  • Based on the manner of culture: Agronomic or Horticultural
  • Based on their use: Food, Fiber, Beverage, Oil, Medicinal
  • Based on their climatic requirement: Temperate, Sub-temperate, Tropical
  • Based on the length of their life cycle: Annuals, Biennials, Perennials
  • Based on their habitat: Aquatic, Terrestrial, Aerial, Arctic
  • Based on their photoperiodic response: Long-day, Short-day, Day-neutral
• Crop Production as a Science:

  • Modern crop production is not based on guesswork or trial and error method
  • Its science is derived from the adoption or application of basic sciences like chemistry, mathematics, physics, and various applied sciences like physiology, meteorology, anatomy, plant breeding, etc
• Crop Production as an Art:

  • It requires skills to produce crops even with little or no scientific training
  • The art of crop science reaches its greatest expression in horticulture, specifically in ornamental horticulture where plants are raised for their aesthetic qualities, e.g. floral arts, as well as in landscaping
• Crop Production as a Business:

  • Plants are grown not only to satisfy the needs of man but also to realize profit in the process of production
  • The maximization of output relative to production input is one of the guiding principles of production
  • Scientific knowledge is utilized to produce plants at the time of high demand and best price, and raising disease-resistant field crops to reduce the cost of crop protectant chemicals
• Contribution of Related Sciences to Crop Production:

  • Crop Breeding and Genetics: Concerned with the improvement of the inherent or heritable properties of crops
  • Botany: Concerned with plant structures, processes, and relationships among plants as well as plant relationship with their environment
  • Soil Sciences: The study of the nature and properties of soils, dealing with the fundamental principles upon which proper soil management is based
  • Plant Pathology and Entomology: Concerned with pathogens, insect pests, and weeds; and their nature, as well as their control
• • Agricultural Engineering: Concerned with farm structures, farm machinery, farm power, water management as well as waste disposal
  • Agricultural Economics: Concerned with the economics of production and marketing of agricultural products
  • Agricultural meteorology: Concerned with the study of weather and climate, enabling weather forecasting to help farmers minimize losses due to bad weather
• The basic knowledge and understanding of the various related disciplines are essential to implement appropriate crop management packages for increasing crop productivity
• Photosynthesis is the manufacture of sugars and its precursors by green plants in the presence of light and chlorophyll
• In photosynthesis, carbon dioxide is reduced by water and fixed as glucose, while oxygen gas formed arises from water, not from CO2
• Carbon dioxide is taken from the air through the stomata, while water is absorbed from the soil by the roots and transported in the xylem to sites of photosynthesis
• About 90% of the world's photosynthetic output occurs in the oceans, with the remaining 10% by land plants
• The main organ for photosynthesis is the leaf, and the main organelle involved is the chloroplastid
• Features that make the leaf an ideal organ for photosynthesis include its expanded form, perpendicular angle to incident light, extensive internal surface with an efficient vascular system, and pigments for light absorption
• Chlorophyll is the principal pigment in photosynthesis, located in the partition between two adjacent thylakoids, with accessory pigments like xanthophyll and carotene
• Photosynthesis consists of two component reactions: Light Reaction, a photochemical process with a requirement for light, and Dark Reaction (Blackman reaction), a thermochemical process that can occur in both light and dark
• The end products of the light reaction, ATP and NADPH, are subsequently used in CO2 fixation, which can occur via the C3 (Calvin-Benson), C4 (Hatch-Slack), or CAM (Crassulacean Acid Metabolism) pathways
• The C3 or Calvin-Benson pathway involves the carboxylation of CO2 by ribulose-1,5-biphosphate (RuBP) using rubisco, leading to the production of 3-phosphoglycerate (3-PGA)
• Photorespiration in C3 plants is a consequence of rubisco's properties, leading to reduced photosynthetic yield
• The C4 or Hatch-Slack pathway in plants involves a more efficient photosynthesis process with a spatial CO2-concentrating mechanism to eliminate photorespiration
• The CAM or Crassulacean Acid Metabolism pathway, found in succulent plants, maximizes water-use efficiency and allows them to thrive in arid environments
• Factors affecting photosynthesis include internal factors like enzymes, genetic factors, leaf age, demand of sinks for photosynthates, water content, and external factors like light quality, intensity, duration, CO2 and H2O availability, temperature, and wind velocity
• Variety - a group of individuals within a species which ate distinct in form/function
• Cultivar - Cultivated variety
• Clone - a group organism descended by mitosis from a common ancestor
• Mitosis


  Vegetative Parts
• Meiosis


  Gametes
• Steps in Crop Production

  1. Site selection and evaluation

  2. Land preparation

  3. Crop establishment

  4. Care and Maintenance

  5. Harvesting and postharvest handling
• Crop establishment

  • Planting materials selection and preparation
  • Lay-outing
  • Planting
• Care and Maintenance

  • Nutrition
  • Water management
  • Pest management
  • Specialized practices
• For every crop species, it will have an ideal environment for its growth. The nearer is the condition for growth to the environmental, the higher is the chance for a successful and profitable crop production.
• Importance of environmental conditions in crop production

  • Determines the crop to plant
  • Determines the kind of production systems
  • Determines the cultural management practices
  • Determines the profitability