Crop Classification

Cheatsheet Content

### Introduction Agronomy focuses on field crop production while sustaining soil resources and the environment. Crops are categorized based on their agronomic, industrial, and nutritional uses to facilitate description and naming. ### Key Concepts - Crops are classified by **agronomic use, nutritional use, life cycle, and climate adaptation**. - **Agronomic crops** include cereals, grains, pulses, forages, fiber crops, cover crops, companion crops, green manure crops, and recreational turf crops. - **Bioenergy** can be produced from grain crops, forage crops, and oil crops. - **Nutritional-use classification** includes sugar crops, oil crops, protein crops, starchy seed crops, and root and tuber crops. - Crops can be grown for **medicinal purposes**. - Many plants are **toxic or deadly** to people and livestock. - Plants are scientifically described using **two-part scientific names** (genus and species). - **Taxonomy** is a system for organizing plants into species, families, orders, classes, and divisions. ### Divisions of Plant Kingdom - A crop is an organism cultivated and harvested for yield. - Plant kingdom divided into two divisions: - **Phanerogams** (flowering plants) further divided into Angiosperms. - **Angiosperms** further divided into two classes: **Monocotyledon & Dicotyledons**. - Classes are divided into orders, orders into families, families into genera & species, sometimes species into varieties. ### Importance of Classifying Crop Plants - Familiarization with crops. - Understanding soil and water requirements for different crops. - Knowing crop adaptability and growing habits. - Understanding climatic requirements. - Knowing the economic produce and use of crop plants. - Knowing the growing season of the crop. ### Classification by Climate - **Tropical:** Crops grow well in warm & hot climates. - **Temperate:** Crops grow well in cool climates. - **In Sri Lanka:** Upcountry Crops, Low Country Crops. ### Classification by Life Cycle (Ontogeny/Duration) - **Annual crops:** Complete life cycle in one season/year (e.g., rice, cassava). - **Biennial crops:** Grow vegetatively in one season, flower/fructify/perish in the next (e.g., sugar beet, carrot). - **Perennial crops:** Live for several years, growing and reproducing (e.g., sugarcane, fruit trees). ### Classification by Growing Season - **Maha season crops:** Grown in monsoon months (Sept/Oct-Nov), requiring warm, wet weather and short day length for flowering (e.g., Rice, Cassava). - **Yala season crops:** Short season crops grown with limited water from April/May to July (e.g., Pulses, Sesame). - **Inter-season crops:** Grown between conventional seasons, requiring warm day weather for major growth and flowering (e.g., Groundnuts, Watermelon, Pumpkins, Gourds). ### Use/Agronomic Classification #### Grain Crops - Cultivated grasses (Poaceae) grown for edible starchy grains. - Larger grains are staple foods (cereals). - Examples: Wheat, rice, corn, barley, sorghum. - **Cereal crops:** Grasses that produce edible grain, storing energy as starch (e.g., wheat, rice, corn). - **Grain crops:** Harvested portion of various grass crops; also includes legumes (soybean, kidney beans) and other plants (flax, buckwheat). Small grains refer to wheat, oat, barley, rye. #### Pulses - Legumes grown for edible, high-protein seeds. - Store energy as carbohydrates or oil. - Seeds borne in pods that burst when mature. - Examples: Soybeans, edible field beans, field peas, lentils, peanuts, chickpeas, cow peas. - Often require cooking to destroy anti-nutritional chemicals. #### Forages - Crops whose vegetative parts (stems, leaves, sometimes seeds/grains) are used for livestock feed. - Can be grazed directly or stored (hay, silage). - Hay: Forage dried to ~20% moisture, stored in air. - Silage: Forage harvested at 50-80% moisture, sealed in a silo. - Important in crop rotations and on erodible lands. #### Fiber Crops - Plants cultivated for fiber used in clothing, rope, paper, baskets. - Examples: - **Cotton:** Surface fiber surrounding seeds, mostly cellulose, white. - **Flax:** Bast fiber (from stem), used for linen, long fibers. - **Hemp:** Coarse, brown bast fiber (from stem), very strong, used for canvas, rope, bags. - **Ramie:** Perennial bast fiber (from bark), harvested multiple times a year. #### Root and Tuber Crops - Harvested for underground storage organs rich in starch. - **Root crops:** Enlarged roots (e.g., sweet potatoes, cassava). - **Tuber crops:** Enlarged underground stems (e.g., white/Irish potatoes, Jerusalem artichoke). #### Green Manure Crops - Legumes or grasses incorporated into soil while vegetative. - Purpose: Add nutrients and enhance soil quality. - Examples: Sweet clover, alfalfa, hairy vetch, crimson clover, winter rye. #### Recreational Turf Crops - Perennial grasses used for recreational purposes (lawns, sports fields, golf courses). - Selected for wear tolerance. - Examples: Kentucky bluegrass, perennial ryegrass, bentgrass, bermuda grass. #### Bio-energy Crops - Production of energy from biological systems (biomass, biofuel). - **Biomass crops:** Burned for heat/electricity (e.g., hybrid poplars, willows, switchgrass, alfalfa). - **Biofuel crops:** Grown specifically for liquid fuel production. - Examples: Corn (starch to ethanol), grain sorghum (starch to ethanol), soybean (oils to biodiesel). #### Sugar Crops - Crops from which sugar is obtained. - Examples: - **Sugar beets:** Root crop for sucrose. - **Sugarcane:** Stores sugar in tall stems. - **Corn:** Source of high fructose corn syrup. - **Sweet sorghum:** Stems pressed for syrup. #### Oil Crops - Produce oil-rich seeds processed for oil. - Oils contain fatty acids. - Examples: Soybean, flax, sunflowers, canola, peanuts, cotton. #### Protein Crops - Seeds naturally high in protein. - Examples: Legumes (soybean, peas, field beans, peanuts), nonlegumes (quinoa, cotton, sunflowers). #### Starchy Seed Crops - Seeds naturally high in starch. - Examples: Cereal grasses (corn, wheat, oat, barley, rye, millet, sorghum), non-grasses (amaranth, buckwheat). #### Starchy Root and Tuber Crops - Roots and tuber crops store energy primarily as starch, converted by humans to energy. #### Drug Crops - Used for preparation of medicines. - Examples: Tobacco, mint, pyrethrum. #### Spices & Condiments - Crop plants whose products flavor, taste, and sometimes color food. - Examples: Ginger, garlic, chili, cumin, onion, coriander, cardamom, pepper, turmeric. #### Vegetable Crops - May be leafy or fruity vegetables. - Examples: Brinjal, tomato. #### Medicinal & Aromatic Crops - Medicinal plants and aromatic plants. - Examples: Cinchona, opium poppy, lemon grass, citronella grass. ### Classification by Cultural Method/Water - **Rain-fed crops:** Grow only on rainwater (e.g., Sesame, Finger millet). - **Irrigated crops:** Grow with the help of irrigation water (e.g., Rice, Sugarcane, Banana). ### Classification by Economic Importance - **Cash crop:** Grown for earning money (e.g., Sugarcane, Chilli, Tobacco). - **Food crops:** Grown for raising food grain for population and fodder for cattle (e.g., Wheat, Rice, Maize, Potato). - **Non-Food crops:** Grown for producing raw materials for different industries (e.g., Rubber, Cotton, Jute, Sugarcane, Soybean). ### The Nightshade Family (Solanaceae) - Diverse family with plants used for food, medicines, drugs, and toxic compounds. - Contains both highly nutritious and poisonous plants. - Species: Potato, tomato, pepper, eggplant, huckleberry, goji berry. - Potato is the fourth most important crop globally. - Tomatoes were initially viewed with suspicion in the Old World due to their Solanaceae family association. ### Important Families of Crop and Weed Plants | Monocot Families | Crops | Weeds | Characteristics | |------------------|-----------------------------|--------------------------------|--------------------------------------------------------------------------------| | Poaceae (Grass) | Barley, Corn, Oat, Wheat, Rice, Sugarcane | Foxtail spp., Fall panicum, Quackgrass, Cheatgrass | ~600 genera, 9000 spp. Widely distributed. Highly specialized leaves, stems, flowers. Mostly hollow stems. | | Cyperaceae (Sedge)| Water chestnut | Nutsedge spp. | Solid, triangular stems. Leaves three-ranked. | | Dicot Families | Crops | Weeds | Characteristics | | Fabaceae (Legume)| Soybean, Peanut, Pea, Vetches, Alfalfa, Clovers | Black medic, Kudzu, Wild licorice | ~630 genera, 18,000 spp. Seeds in pods. Biological N₂ fixation. Rich in protein. | | Solanaceae (Nightshade)| Potato, Tomato, Tobacco, Pepper | Nightshade, Jimsonweed | ~85 genera, 2800 spp. Contains alkaloids. | | Convolvulaceae (Morning-glory)| Sweet potato | Field bindweed, Dodder | Viny herbage. Leaves frequently heart- or arrow-shaped. | | Asteraceae (Sunflower)| Sunflower, Artichoke | Dandelion, Thistle, Ragweed | Largest family with ~1100 genera, 20,000 spp. Head inflorescences. | | Chenopodiaceae (Goosefoot)| Sugar beet, Quinoa, Spinach | Lambsquarters, Kochia, Russian thistle | Taprooted succulent annuals. Leaves like goosefoot. Small, greenish flowers. | | Amaranthaceae (Amaranth)| Amaranth | Pigweed, Waterhemp | Taprooted herb. Very small flowers. | | Polygonaceae (Buckwheat)| Buckwheat, Rhubarb | Smartweed, Knotweed | Pungent acid juice in stem. | | Linaceae (Flax) | Flax | | Annual with fibrous stem. | | Brassicaceae (Mustard)| Canola, Mustard, Turnip | Garlic mustard, Shepardspurse | Many winter annuals and biennials. Herbage and roots often produce pungent odor. Petals often form cross. | | Cucurbitaceae (Squash)| Squash, Cantaloupe, Pumpkin | | ~90 genera, 700 annual spp. Viny crops with large, fleshy fruits. Large, bright flowers often unisexual. | | Malvaceae (Mallow)| Cotton, Okra | Velvetleaf, Mallow | ~204 genera, 2300 spp. Have mucilaginous sap. |