Chap 3- Agronomy as a science Flashcards
What is agronomy?
Agronomy is the science and technology of using plants for food, fuel, fiber, and land reclamation.
What does the Greek root of ‘agronomy’ mean?
Agros means field and Nomos means to manage.
What is the main focus of agronomy?
The management of soil resources to produce crops sustainably.
Where was the earliest planned harvesting of plants identified?
The Middle East.
What is plant domestication?
The process of selecting plants for cultivation from wild varieties.
When was the scientific approach to crop production introduced?
1834 at Rothamsted Experimental Station, UK.
Name three fundamental sciences that agronomy is derived from.
Botany, Chemistry, and Physics.
What are two new dimensions in crop production systems?
Biotechnology and Hydroponics.
What are the two basic components of agronomy?
Crop and Soil.
List three subfields under crop components of agronomy.
Crop physiology, Plant breeding, and Horticulture.
List three subfields under soil components of agronomy.
Soil Biology, Soil Physics, and Soil Chemistry.
What are the steps in crop production?
Land clearing, Tillage, Planting, Weeding, Fertilizer application, Pest control, Harvesting, and Processing.
What is mixed cropping?
Planting more than one crop on a field at the same time.
Define relay cropping.
Planting a new crop toward the end of the current crop’s life cycle.
What is crop rotation?
The systematic planting of different crops in a sequence on the same land.
What determines crop yield expectancy in Nigeria?
Climate, length of the rainy season, and vegetation.
What is desertification’s impact on crop production?
It reduces ecological zones to one season, causing environmental degradation and decreased productivity.
How are crops classified agronomically?
By their use: e.g., cereals, legumes, root crops, fibre crops, etc.
Name two examples of cereals.
Maize and Rice.
Name two examples of legumes.
Cowpea and Soybean.
Name two examples of root and tuber crops.
Cassava and Yam.
What is the definition of soil?
The collection of natural bodies on the Earth’s crust that supports plants.
What is a soil profile?
A vertical succession of horizontal layers of soil.
List the four components of surface soil by volume composition.
Minerals (45%), Water (25%), Air (25%), Organic matter (5%).
What is soil texture?
The relative proportion of sand, silt, and clay in the soil.
What is loam soil?
An ideal soil with 6-28% clay, 28-50% silt, and 24-52% sand.
What determines soil reaction (pH)?
The balance of acidity or alkalinity, with pH values ranging from 0-14.
What are macronutrients in plants?
Nutrients needed in large quantities, e.g., Nitrogen, Phosphorus, Potassium.
What are micronutrients in plants?
Nutrients needed in small quantities, e.g., Iron, Zinc, Boron.
What are the three primary macronutrients?
Nitrogen (N), Phosphorus (P), and Potassium (K).
What is organomineral fertilizer?
A blend of organic and mineral fertilizers.
What are biofertilizers?
Microorganisms used to improve soil fertility, e.g., Rhizobium and Mycorrhiza.
List one source of nitrogen for fertilizers.
Urea.
What are the major soil types in Nigeria?
Alfisols, Entisols, Inceptisols, Oxisols, Ultisols, and Vertisols.
What percentage of Nigerian soil is Alfisols?
40%.
Where are Oxisols commonly found in Nigeria?
South-Eastern states.
What is organic agriculture?
A system that promotes environmentally, socially, and economically sustainable production without synthetic inputs.
What are the four principles of organic agriculture?
Health, Ecology, Fairness, and Care.
What is ecological agriculture?
The integration of ecological principles with farming practices.
Name two problems associated with Nigerian soil management.
Low organic matter and high susceptibility to erosion.
What is the importance of soil organisms?
They enhance soil structure, nutrient recycling, and aeration.
What is the current trend in fertilizer use?
The use of organomineral fertilizers for sustainability.
What are the sources of potassium in fertilizers?
Muriate of Potash (KCl) or Potassium Nitrate.
What is the pH range for acidic soil?
Less than 7.
What causes soil degradation in tropical regions?
High temperatures, erosion, and low organic matter.
What is minimum tillage?
Limiting soil disturbance to conserve soil quality.
What is the textural triangle used for?
Determining the textural class of soil.
What is the composition of organic matter in good agricultural soil?
3-5%.
What are the benefits of mixed cropping?
Improved soil cover, nutrient cycling, and pest management.
