Tillage, Seeds, Sowing, and Crop Management Flashcards

AGRICULTURE: DEFINITION AND MEANING

• Etymology: The term Agriculture is derived from two Latin words:
  • ager or agri: Meaning soil, land, or field.
  • cultura: Meaning cultivation.
• Broad Definition: Agriculture is a broad term covering all aspects of crop production, livestock farming, fisheries, forestry, etc.
• Art and Science Definition: It is defined as the art and science of cultivating land, raising crops, and feeding, breeding, and raising livestock.
• Functional Definition: The cultivation of lands for production of crops for a regular supply of food and other needs for the progress of the nation.
• Spheres of Agriculture:
  1. Geoponic: Cultivation in earth.
  2. Hydroponic: Cultivation in water.
  3. Aeroponic: Cultivation in air.
• Importance: Considered the "mother of all Agro-based industries" as it supplies raw materials to different industries.
• Nature of Indian Agriculture: Predominantly of the subsistence type.

AGRONOMY: DEFINITION, MEANING, AND ROLE

• Etymology: Derived from Greek words:
  • agros: Meaning field.
  • nomos: Meaning management.
• Basic Definition: A specialized branch of agriculture dealing with crop production and soil management.
• Technical Definition: An agricultural science dealing with the principles and practices of soil, water, and crop or field management.
• Norman (1980) Definition: The science of manipulating the crop environment complex with the dual aims of improving agricultural productivity and gaining a degree of understanding of the processes involved.
• Role of the Agronomist:
  • A scientist who studies problems of crop production and adopts/recommends practices for better field crop production and soil management to achieve high yield and income.
  • Aims for maximum production at minimum cost.
  • A key person with working knowledge of all agricultural disciplines and acts as a coordinator of different subject matter specialists.
  • Concerned with producing food and fiber to meet the needs of a growing population.

TILLAGE AND TILTH

• Etymology of Tillage: Derived from Anglo-Saxon words tilian and teolian, meaning to plough and prepare soil for seed to sow, to cultivate, and to raise crops.
• Historical Context: Jethro Tull, the Father of Tillage, suggested that thorough ploughing is necessary to make the soil into fine particles.
• Soil Compaction Post-Harvest: After harvest, soil becomes hard/compact due to:
  • Beating action of raindrops.
  • Irrigation followed by drying.
  • Movement of inter-cultivation implements and labour.
• Definition of Tillage: The mechanical manipulation of soil with tools and implements for obtaining conditions ideal for seed germination, seedling establishment, and growth of crops.
• Definition of Tilth: The physical condition of soil obtained through tillage. It is the resultant effect where soil air, soil water, and soil aggregates are in perfect harmony or balanced condition.
• Purpose of Tillage: To prepare a seedbed, break weed, insect, and disease cycles, bury plant residues, incorporate fertilizers and amendments, and break surface crust.
• Primary Objectives of Tillage:
  1. Seedbed preparation for good germination and growth.
  2. Making soil loose and porous.
  3. Providing soil aeration.
  4. Weed control (considered one of the most important objectives).
  5. Stubbles removal to eliminate pest harbors.
  6. Exposing soil pathogens and insect pests to the sun for sterilization.
  7. Breaking hard pans.
  8. Deep tillage and soil inversion.
  9. Incorporating bulky organic manures.
  10. Increasing infiltration rate.

TYPES AND CATEGORIES OF TILLAGE

• Tillage operations are grouped based on the time relative to the crop.

1. Preparatory Tillage

Operations carried out to prepare the field for raising crops, from the time of harvest of a previous crop until the sowing of the next crop.

• A) Primary Tillage (Ploughing):

  • The first operation done after harvest to bring land under cultivation.
  • Aims to open hard soil, separate top soil from lower layers, and uproot weeds/stubbles.
  • Example implements: Country plough, Disc plough, Mould board plough.
  • Subtypes of Primary Tillage:
    1. Deep Tillage: Classified by CRIDA (Hyderabad) as follows:
       • Shallow: $5-6\,cm$ depth.
       • Medium Deep: $15-20\,cm$ depth.
       • Deep: $25-30\,cm$ depth.
       • Benefit: Kills rhizomes, tubers of perennial weeds, and insect pupae via sun exposure; improves moisture storage.
    2. Sub-soiling: Breaking hard pans (silt, iron, aluminum, clay, or man-made) without inversion and with minimal topsoil disturbance. Uses a sub-soiler or chisel plough to reach depths of $60-70\,cm$.
    3. Year-round Tillage: Operations performed throughout the year.
    4. Tied Ridging: Formation of ridges connected by small cross-bunds to enhance response to rainfall and fertilizer.

• B) Secondary Tillage:

  • Lighter, finer operations performed after primary tillage.
  • Includes sowing operations.
  • Example implements: Disc harrows, cultivators, blade harrows, planking.
  • Specific Operations:
    1. Harrowing: Breaking clods, leveling land, and uprooting weeds using spikes or disks.
    2. Planking: Crushing clods and smoothing the surface before seeding.

2. After-Tillage (Inter-cultivation)

Operations carried out in the standing crop.

• Harrowing and Hoeing: Using long-handled implements with blades to till soil and erratic weeds.
• Inter-cultivation: Cultivating soil between crop rows to improve aeration and loosen compaction.
• Earthing Up: Raising soil at the plant base to provide support against lodging and encourage root penetration.
• Weeding: Eliminating weeds by hand or tool.

MODERN CONCEPTS OF TILLAGE

• Traditional/Conventional tillage involves primary followed by secondary tillage but can lead to hard pans, poor infiltration, erosion, and high costs.
• Father of Modern Tillage: Dr. G.B. Triplett.

1. Minimum Tillage

Reducing tillage to the minimum necessary for a good seedbed, germination, and stand.

• Methodology: Omitting non-beneficial operations or combining operations (e.g., seeding + fertilizer application).
• Advantages: Improved soil conditions via in-situ decomposition; higher infiltration; less resistance to root growth; less compaction and erosion.
• Disadvantages: Lower germination; slower organic matter decomposition (requires higher Nitrogen); difficult sowing with standard equipment; potential herbicide pollution.

2. Zero Tillage (No-Till)

An extreme form of minimum tillage where primary tillage is avoided entirely and secondary tillage is restricted to the row zone.

• Key Traits:
  • Increase in organic matter due to less mineralization.
  • Mulch presence reduces surface runoff.
  • Requires vegetation destruction using broad-spectrum, non-selective herbicides (e.g., Paraquat, Glyphosate) before sowing.
  • Requires selective herbicides in later stages.
  • Seedling establishment is often $20\,\%$ less than conventional methods.
  • Requires higher Nitrogen doses due to slow mineralization.

LAND CONFIGURATION TECHNIQUES

• Goal: Minimize erosion, improve water use efficiency (WUE), and provide uniform germination.

1. Flat Beds: Prepared in sandy loam soil; easy to work.
2. Raised Beds: Preferred for heavy black soil with high water holding capacity and poor drainage. Dimensions typically $10.0\,m \times 1.0\,m$.
3. Ridges and Furrows: Furrows ($30-45\,cm$ width, $15-20\,cm$ height) formed across the slope. Suitable for medium to deep black/red soils and wide-row crops like cotton, maize, chilles.
4. Tied Ridging: Modification of ridges where furrows are tied by small bunds every $2-3\,m$ to collect rainwater. Recommended by ICRISAT for black soils in high rainfall regions ($> 750\,mm$).
5. Broad Bed Furrows (BBF): Beds $90-120\,cm$ wide and $15\,cm$ high, separated by furrows $60\,cm$ wide and $15\,cm$ deep.
   • Advantages: Moisture storage, safe disposal of runoff, better drainage, facilitates dry seeding, accommodates sole or intercropping.
6. Dead Furrows: Deep furrows ($20\,cm$ depth) formed every $6$ to $8$ rows. No crop is grown in them. Enhances infiltration in red soils.
7. Scooping: Forming small depressions to retain rainwater and trap sediment. Can reduce runoff by $50\,\%$ and soil loss by $3-8\,t/ha$.

SEEDS: DEFINITION AND QUALITY

• Definition: A fertilized ovule consisting of an intact embryo, stored food, and a seed coat; it is viable and capable of germinating under favorable conditions.
• Characteristics of Good Quality Seeds:
  • True to type.
  • Free from inert materials, weed seeds, insects, and disease spores.
  • High viability and standard germination capacity.
  • Uniform texture and structure.
  • Optimum moisture: $6-8\,\%$ for long-term storage; $10-13\,\%$ for short-term.
  • Source: Fully matured, bold, and plump.
• Quality Metrics:
  • Viability: Expressed as germination percentage (number of seedlings produced per seeds planted).
  • Vigour: Indicated by high germination percentage, high rate, and quick growth. Vital for withstanding crusting or deep planting.
  • Germination Rate: Measured by days required for radical/plumule emergence.

CLASSES OF SEED

1. Nucleus Seed (Basic Seed): $100\,\%$ genetically and physically pure. Produced by the original breeder. Not for general distribution.
2. Breeder Seed: $99.90\,\%$ genetically pure. Produced at breeder's institute. Tag color: Golden/Yellow. Tag size: $12 \times 6\,cm$.
3. Foundation Seed ("Mother Seed"): $99.5\,\%$ genetically pure. Produced from breeder seed at State Government or University farms. Tag color: White. Tag size: $15 \times 7.5\,cm$.
4. Registered Seed: Produced from foundation seed by private growers or companies. Tag color: Purple. Tag size: $15 \times 7.5\,cm$.
5. Certified Seed: $99\,\%$ genetically pure. Commercial seed sold to farmers. Produced from foundation or registered seed, certified by State Seed Certification Agency. Tag color: Blue. Tag size: $15 \times 7.5\,cm$.
6. Truthfully Seed: Progeny of certified or registered seed, supervised by the farmer. Tag color: Opal Green. Tag size: $15 \times 10\,cm$.

SOWING PRINCIPLES AND METHODS

Time of Sowing

• Early Sowing: Can be risky (e.g., rainfed groundnut in June if dry spells follow) but beneficial for rabi sorghum (Sept-Oct) to use residual moisture.
• Delayed Sowing: Reduces yields due to early flowering (short-day plants), unfavorable temp, and increased pests (e.g., shoot borer in late sorghum).
• Optimum Time:
  • Tropical crops: June-July (monsoon onset).
  • Temperate (wheat/barley): Last week of Oct to first week of Nov.
  • Summer crops: First fortnight of January.

Types and Methods of Sowing

1. Dry Sowing: Sowing in dry soil $7-10$ days before anticipated rains. Used in black soils.
2. Wet Sowing: Common method; requires minimum $20\,mm$ rainfall.
3. Broadcasting: Scattering seeds by hand.
   • Pros: Cheap, easy, quick.
   • Cons: Higher seed rate, uneven distribution/depth, difficult weeding.
4. Drilling: Dropping seeds in furrows at row distance using mechanical devices.
   • Pros: Uniform row distance, lower seed rate than broadcasting, allows inter-cultivation.
   • Cons: No distance maintained within rows; requires thinning.
5. Dibbling: Placing seeds in holes at predetermined spacing/depth.
   • Pros: Precision spacing, low seed rate, selection of good seeds, uniform vigour.
   • Cons: Laborious, expensive, time-consuming. Examples: Cotton, Pigeon pea.
6. Planting: Placing vegetative propagules (tubers, rhizomes, etc.) in soil. Example: Potato (Tuber), Sugarcane (Setts), Ginger (Rhizomes).
7. Transplanting: Uprooting seedlings from a nursery and planting in a field.
   • Pros: Economy of costly seeds, healthy stand, better care in early stages.
   • Cons: Increased labor/cost, longer total duration.

CROP DENSITY AND GEOMETRY

• Plant Population/Density: Number of plants per unit area.
• Optimum Plant Population: Number of plants required to produce maximum biomass/output per unit area. Beyond this, yield decreases or plateaus.
• Plant Geometry: Shape of the plant canopy (e.g., vertical in sorghum, horizontal in cotton).
• Crop Geometry: Arrangement of plants in rows/columns for resource utilization (e.g., $20\,cm \times 15\,cm$ for rice).

Types of Geometries

1. Random Geometry: From broadcasting; inefficient resource use.
2. Square Geometry: Equal distance on all sides. Used in fruit trees/perennial crops. Allows uniform light and mechanization.
3. Rectangular Geometry: Row spacing wider than plant spacing.
   • Solid Row: General arrangement.
   • Paired Row: Altered spacing (e.g., $75-120-75\,cm$) to allow intercropping between pairs.
   • Skip Row: Skipping a row; reduction in population is offset by intercrops in dryland systems.
4. Triangular Method: Recommended for wide-spaced crops like coconut/mango.
5. Quincunx (Diagonal) System: Square system plus a central "filler" tree; nearly doubles plant count.
6. Hexagonal System: Six trees forming a hexagon with a seventh in the center. Increases population by $15\,\%$ over square method. Requires fertile, irrigated soil.
7. Contour System: Sowing across slopes in hilly regions.

Response Curves for Plant Population

• Asymptotic Response: In fodder or tobacco crops where total biomass is the product; yield plateaus and remains constant.
  • Formula: $Y = \frac{Ap}{1+Abp}$
  • Where $Y = \text{Yield}$, $A = \text{Max yield per plant}$, $p = \text{plants/unit area}$, $b = \text{regression coefficient}$.
• Parabolic Response: For grain crops where yield is a fraction of biomass; yield increases to a maximum and then decreases.
  • Formula: $Y = a + bp + cp^2$

CROP NUTRIENT MANAGEMENT (CNM) AND NUE

• CNM: Planning and applying nutrients based on soil tests and crop needs.
• Components:
  • Soil Testing.
  • Sources: Organic (manure, compost) and Inorganic (N, P, K fertilizers).
  • Timing/Placement: Right time for critical growth stages; precision placement to reduce loss.
  • Integrated Nutrient Management (INM): Combining organic/inorganic sources.
• Nutrient Use Efficiency (NUE/FUE): Yield per unit fertilizer input or recovery percentage.
• Strategies to Improve NUE:
  1. Right Rate: Based on calibrated soil tests.
  2. Right Time: Synchronization with crop demand; split applications of Nitrogen.
  3. Right Place: Placement that maximizes root uptake.
  4. Modified Fertilizers: Slow-release fertilizers and nitrification inhibitors (e.g., nitrapyrin, DCD, NBPT) to slow conversion to nitrate.

PLANT IDEOTYPES

• Term Origin: Proposed by Donald (1968) working on wheat.
• Definition: A biological model or "ideal plant type" expected to perform predictably in a defined environment to produce higher yields.
• Ideotype Breeding: Genetic manipulation of individual traits (morphological/physiological) rather than yield alone.

Crop Specific Ideotype Features

• Wheat (Donald): Short strong stem, erect leaves, few small leaves (less transpiration), larger ear, erect ear, presence of awns.
• Barley (Rasmusson): Short stature, long awns, high Harvest Index (HI), high biomass.
• Cotton (Irrigated): Short stature ($90-120\,cm$), pyramidal shape, short duration ($150-165\,days$), pest resistance.
• Cotton (Rainfed): Earliness, small/thick leaves, indeterminate habit, sparse hairiness.
• Maize (Mock and Pearce): Stiff vertically-oriented leaves, high photosynthetic efficiency, short pollen-to-silk interval, cold tolerance.
• Rice: Semi-dwarf, high tillering, erect/thick leaves, high HI ($55\,\%$ or more).

CROP ADAPTATION AND DISTRIBUTION

Types of Adaptation

1. Morphological: Growth habit, stalk length.
2. Physiological: Resistance to parasites, desiccation survival.
3. Specific Genotypic: Adoption to limited environment (e.g., deep-water rice varieties).
4. General Genotypic: Stability over wide environments (e.g., semi-dwarf wheat).
5. Specific Population: Heterogeneous population adapted to one environment.
6. General Population (Homeostasis): Heterogeneous population adapted to various environments (e.g., synthetic forage crops).

Factors of Crop Distribution

• Climatic Factors:
  • Precipitation: Primary key to growth.
  • Relative Humidity: Optimum $40-60\,\%$. High humidity triggers pests.
  • Temperature: Growth range $15-40\,\text{°C}$. Plants fail below $6\,\text{°C}$ (noted as $60\,\text{°C}$ in original text, likely typo for $6\,\text{°C}$ or referring to frozen soil thresholds).
  • Solar Radiation: Photosynthetically Active Radiation (PAR $0.4-0.7\,u$).
  • Wind: Supply of $CO_2$; pollination. High speeds ($> 4-6\,km/h$) cause erosion and lodging.
• Global Distribution Rankings:
  • Wheat: China (1st), India (2nd).
  • Rice: China (1st), India (2nd), Indonesia (3rd).
  • Maize: USA (1st), China (2nd), Brazil (3rd).
  • Sugar Cane: Brazil (1st), India (2nd).
  • Soybean: USA (1st), Brazil (2nd).