AGRONOMY : COMPLETE NOTES
Unit 1: Introduction to Agronomy
1. Basics & Etymology
- Derivation: The term "Agronomy" comes from Greek words "Agros" (field) and "Nomos" (to manage).
- Definition: Branch of agriculture dealing with principles and practices of managing soil, water, and crops.
- Father of Agronomy: Pietro de Crescenzi (Italy).
- Key Organizations:
- American Society of Agronomy: Established in 1908.
- Indian Society of Agronomy: Established in 1955.
2. Key Concepts
- Plant Geometry: Refers to the shape of the plant, whereas Crop Geometry refers to the shape of land occupied by plants (determined by inter-row and intra-row spacing).
- Sustainable Agriculture: Meets current needs without compromising future generations' ability to meet their needs. Focus: Environmental health, economic viability, social equity.
- Precision Agriculture:
- Uses advanced tech (GPS, sensors) to optimize field-level management.
- Also called: Site-specific farming, Smart farming, Variable Rate Technology (VRT).
- Origin: Initiated in the USA in 1980s.
Unit 2: Field Crop Production
1. Important "Kings" and "Queens" (Exam Hack)
Title | Crop |
King of Cereals | Wheat |
Queen of Cereals | Maize |
King of Pulses | Chickpea |
Queen of Pulses | Pea |
King of Oilseeds | Groundnut |
Queen of Oilseeds | Sesame |
King of Fodder | Berseem |
Queen of Fodder | Lucerne |
King of Coarse Cereals | Sorghum |
Wonder Crop / Poor Man’s Meat | Soybean |
White Gold / King of Fibers | Cotton |
Queen of Beverages | Tea |
2. Cereal Crops
A. Rice (Oryza sativa)
- Origin: Southeast Asia (Indo-Burma).
- Statistics: Staple for >60% of the world. India has the largest area, but China leads in production.
- Rice Bowl of India: Andhra Pradesh (Krishna-Godavari delta) and Chhattisgarh.
- Classification:
- Indica: Tropical/Subtropical (India).
- Japonica: Temperate (Japan), high input responsive.
- Javanica: Indonesia (Balu rice).
- Varieties:
- TN-1: First semi-dwarf variety introduced in India (1964).
- IR-8: "Miracle Rice," high yielding semi-dwarf.
- Jaya: "Miracle Rice in India" (First biological variety developed here).
- Pusa Basmati-1: First high-yielding semi-dwarf aromatic variety.
- Sowing Seasons (Hack: Remember "A-A-B"):
- Aus (Autumn): Sown May-June.
- Aman (Winter): Sown June-July (Main season, 84% of area).
- Boro (Summer): Sown Dec-Jan (Highest productivity).
- Methods:
- Dapog Method: From Philippines. Seedlings ready in 11-14 days. No soil used.
- SRI (System of Rice Intensification): Developed in Madagascar. Seed rate 5-8 kg/ha. Transplanting at 8-10 days old.
- Critical Issues:
- Khaira Disease: Caused by Zinc deficiency. Treated with Zinc Sulphate + Lime.
- Akiochi Disease: Caused by Hydrogen Sulphide (H_2S) toxicity in low-lying soils.
- White Belly: Caused by chalky endosperm.
- Gas Emission: Rice fields emit Methane (CH_4).
B. Wheat (Triticum aestivum)
- Origin: South West Asia (Turkey).
- Chromosomes: Hexaploid (2n=6x=42).
- Green Revolution: Triggered by Norin-10 gene (dwarfing gene from Japan). Key scientist: N.E. Borlaug (World) and M.S. Swaminathan (India).
- Classification:
- T. aestivum: Bread wheat (95% area in India).
- T. durum: Macaroni wheat (good for suji/seviyan).
- Important Varieties:
- HD-2329: Contributed most to Green Revolution.
- Sonalika, Kalyan Sona: Semi-dwarf varieties.
- Irrigation Stages (Hack: CRI is Critical):
- CRI (Crown Root Initiation): 20-25 DAS (Most Critical).
- Tillering.
- Jointing.
- Flowering.
- Milking.
- Dough.
- Weed Control: Phalaris minor (Canary grass) is the major mimicry weed. Controlled by Isoproturon (formerly) or Sulfosulfuron.
C. Maize (Zea mays)
- "Queen of Cereals" and "Miracle Crop" (highest yield potential).
- Protein: Zein (deficient in Lysine and Tryptophan).
- Roots: Seminal, Adventitious, and Prop/Brace roots (support from lower nodes).
- Types:
- Dent Corn: Common in USA (Z. m. indentata).
- Flint Corn: Common in India (Z. m. indurata).
- Sweet Corn: Eaten vegetable (Z. m. saccharata).
- Quality Protein Maize (QPM): Developed by S.K. Vasal and E. Villegas (World Food Prize winners). Rich in Lysine/Tryptophan. Varieties: Shakti-1, Shaktiman-1.
D. Millets
- Pearl Millet (Bajra): Highest mineral (2.7%) and fat (5%) among cereals. Drought tolerant. Origin: West Africa.
- Sorghum (Jowar): "Camel Crop" (drought resistant). "King of Coarse Cereals". Contains HCN (Prussic acid) in early stages (<55 days), toxic to cattle.
- Finger Millet (Ragi): Rich in Calcium. Staple in Karnataka.
3. Pulses
- Nitrogen Fixation: All pulses fix N except Rajma (French Bean).
- Chickpea (Gram): King of Pulses. Sour taste due to Malic Acid (90-96%) and Oxalic Acid. Critical stage: Pod formation.
- Desi: Small, darker.
- Kabuli: Large, white.
- Pigeon Pea (Red Gram/Tur): Long duration crop. Varieties: UPAS-120 (short duration).
- Lathyrus: Causes Lathyrism (paralysis) due to Neurotoxin ODAP/BOAA. Steep seeds in hot water to remove.
4. Oilseeds
- Groundnut: "King of Oilseeds." Fruit type: Lomentum.
- Pegging: Gynophore enters soil to form pods (30-55 DAS).
- Aflatoxin: Toxin produced by Aspergillus flavus in stored moist kernels.
- Soybean: "Boneless Meat." 40-42% Protein, 20% Oil. Nodule bacteria: Rhizobium japonicum.
- Rapeseed & Mustard: Pungency due to Glucosinolates (Sinigrin). Fruit is Siliqua.
- Canola: 0% Erucic acid and low glucosinolates.
- Sunflower: Indicator plant for Boron deficiency. Head shows Heliotropism (moves with sun).
5. Fiber & Cash Crops
- Cotton: "White Gold."
- Bt Cotton: Developed to kill bollworms (Cry1Ac gene).
- Ginning %: (Weight of lint / Weight of seed cotton) x 100.
- Jute: "Golden Fiber." Retting temperature: 34°C is optimal.
- Sugarcane:
- S. officinarum: Noble cane (thick, juicy).
- S. barberi: Indian cane.
- Planting: Sets (top 1/3 used because glucose rich).
- Operations: Wrapping, Propping (to prevent lodging), Detrashing.
Unit 3: Farming Systems & Indices
1. Systems
- Monocropping: Growing same crop year after year (100% Cropping Intensity).
- Relay Cropping: Planting succeeding crop before harvesting the preceding one (e.g., Paira/Utera). "Relay race" concept.
- Alley Cropping: Growing arable crops between hedgerows of trees.
Unit 4: Water Management
1. Irrigation Methods
- Surface:
- Check Basin: Most common in India (95%). Suitable for close-growing crops (Wheat, Groundnut).
- Furrow: For row crops (Maize, Potato, Sugarcane).
- Micro-Irrigation:
- Drip: Developed by Simcha Blass (Israel). Highest efficiency (90%). Saves 50-70% water. Not for rice.
- Sprinkler: Efficiency 60%. Good for undulating (uneven) land and sandy soil. Avoid in high wind.
2. Water Requirements (WR)
- Highest WR: Rice (900-2500 mm) & Sugarcane (1500-2500 mm).
- Lowest WR: Millets (Sorghum/Bajra).
- Measurement:
- Lysimeter: Measures Evapotranspiration (ET).
- Tensiometer: Measures soil moisture tension (effective up to 0.85 bar).
Unit 5: Dryland Agriculture
1. Classification
- Dry Farming: < 750 mm rainfall. (Crop failure frequent).
- Dryland Farming: 750 - 1150 mm rainfall.
- Rainfed Farming: > 1150 mm rainfall.
2. Watershed Management
- Watershed: Hydrological unit where water drains to a common point.
- Sizes: Mini (<100 ha) to Macro (>50,000 ha).
Unit 6: Tillage
- Father of Tillage: Jethro Tull (Book: Horse Hoeing Husbandry).
- Zero Tillage: Father: Garber & Glubler. Primary tillage is avoided; direct sowing. Herbicide Paraquat is commonly used.
- Minimum Tillage: Father: E.H. Faulkner (Book: Plowman’s Folly).
Unit 7: Organic Farming
- Father: Sir Albert Howard.
- Term Coined By: Lord Northbourne (Book: Look to the Land).
- Status: Sikkim is the first 100% organic state in the world/India.
- Certifying Agency: NPOP (National Programme for Organic Production) launched in 2001.
- Biofertilizers:
- Rhizobium: For legumes.
- Azotobacter: Free-living, for cereals.
- Azolla: Water fern for Rice.
Unit 8: Weed Science
- Definition: "Plant growing out of place." Term coined by Jethro Tull.
- Institute: Directorate of Weed Research (DWR) is in Jabalpur, MP.
- Classification (Life Cycle):
- Annual: Complete in 1 season (e.g., Phalaris minor).
- Perennial: >2 years (e.g., Cyperus rotundus - World's worst weed).
- Parasitic Weeds (TRICK: C-L-O-S):
- Cuscuta (Dodder): Total Stem parasite (Lucerne).
- Loranthus: Partial Stem parasite (Mango/Plantation).
- Orobanche (Broomrape): Total Root parasite (Mustard/Tobacco/Tomato).
- Striga (Witch weed): Partial Root parasite (Sorghum/Maize).
- Herbicides:
- 2,4-D: First organic herbicide (1944). Selective for broad-leaf weeds.
- Pre-emergence: Applied after sowing but before germination (e.g., Pendimethalin).
- Post-emergence: Glyphosate, Isoproturon.
Unit 9: Important Agricultural Facts (General)
- Total Food Grain Production (2023-24): 328.85 million tonnes.
- Highest Fertiliser Consumption: Puducherry (UT), Punjab (State) .
- Remote Sensing: Father in India is Dr. P.R. Pisharoty.
- Famous Books:
- Horse Hoeing Husbandry - Jethro Tull.
- Plowman’s Folly - E.H. Faulkner.
