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Season Extension
Season extension in agriculture is any method that allows a crop to be grown beyond its normal outdoor growing season and harvesting time frame, or the extra time thus achieved. To extend the growing season into the colder months, one can use unheated techniques such as floating row covers, low tunnels, caterpillar tunnels, or hoophouses. However, even if colder temperatures are mitigated, most crops will stop growing when the days become shorter than 10 hours, and resume after winter as the daylight increases above 10 hours. A hothouse — a greenhouse which is heated and illuminated — creates an environment where plants are fooled into thinking it is their normal growing season. Though this ''is'' a form of season extension for the grower, it is not the usual meaning of the term. Season extension can apply to other climates, where conditions other than cold and shortened period of sunlight end the growing year (e.g. a rainy season). Structures * Unheated greenhouses (also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agriculture
Agriculture encompasses crop and livestock production, aquaculture, and forestry for food and non-food products. Agriculture was a key factor in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to live in the cities. While humans started gathering grains at least 105,000 years ago, nascent farmers only began planting them around 11,500 years ago. Sheep, goats, pigs, and cattle were domesticated around 10,000 years ago. Plants were independently cultivated in at least 11 regions of the world. In the 20th century, industrial agriculture based on large-scale monocultures came to dominate agricultural output. , small farms produce about one-third of the world's food, but large farms are prevalent. The largest 1% of farms in the world are greater than and operate more than 70% of the world's farmland. Nearly 40% of agricultural land is found on farms larger than . However, five of every six farm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermosiphon
A thermosiphon (or thermosyphon) is a device that employs a method of passive heat transfer, heat exchange based on natural convection, which circulates a fluid without the necessity of a mechanical pump. Thermosiphoning is used for circulation of liquids and volatile gases in heating and cooling applications such as heat pumps, water heaters, boilers and furnaces. Thermosiphoning also occurs across air temperature gradients such as those occurring in a wood-fire chimney or solar chimney. This circulation can either be open-loop, as when the substance in a holding tank is passed in one direction via a heated transfer tube mounted at the bottom of the tank to a distribution point — even one mounted above the originating tank — or it can be a vertical closed-loop circuit with return to the original container. Its purpose is to simplify the transfer of liquid or gas while avoiding the cost and complexity of a conventional pump. Simple thermosiphon Natural convection of the liq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coliform Bacteria
Coliform bacteria are defined as either motile or non-motile Gram-negative non- spore forming bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35–37 °C. They can be aerobes or facultative aerobes, and are a commonly used indicator of low sanitary quality of foods, milk, and water. Coliforms can be found in the aquatic environment, in soil and on vegetation; they are universally present in large numbers in the feces of warm-blooded animals as they are known to inhabit the gastrointestinal system. While coliform bacteria are not normally the cause of serious illness, they are easy to culture, and their presence is used to infer that other pathogenic organisms of fecal origin may be present in a sample, or that said sample is not safe to consume. Such pathogens include disease-causing bacteria, viruses, or protozoa and many multicellular parasites. Every drinking water source must be tested for the presence of these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Mulch
Plastics are a wide range of synthetic or semisynthetic materials composed primarily of polymers. Their defining characteristic, plasticity, allows them to be molded, extruded, or pressed into a diverse range of solid forms. This adaptability, combined with a wide range of other properties such as low weight, durability, flexibility, chemical resistance, low toxicity, and low-cost production, has led to their widespread use around the world. While most plastics are produced from natural gas and petroleum, a growing minority are produced from renewable resources like polylactic acid. Between 1950 and 2017, 9.2 billion metric tons of plastic are estimated to have been made, with more than half of this amount being produced since 2004. In 2023 alone, preliminary figures indicate that over 400 million metric tons of plastic were produced worldwide. If global trends in plastic demand continue, it is projected that annual global plastic production will exceed 1.3 billion tons by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mulch
A mulch is a layer of material applied to the surface of soil. Reasons for applying mulch include conservation of soil moisture, improving soil fertility, fertility and health of the soil, reducing Weed control, weed growth, and enhancing the visual appeal of the area. A mulch is usually, but not exclusively, organic in nature. It may be permanent (e.g. plastic sheeting) or temporary (e.g. barkdust, bark chips). It may be applied to bare soil or around existing plants. Mulches of manure and compost will be incorporated naturally into the soil by the activity of worms and other organisms. The process is used both in commercial crop production and in gardening, and when applied correctly, can improve soil productivity. Living mulches include moss lawnsMoss Myths/ref> and other ground covers. Uses Many materials are used as mulches, which are used to retain soil moisture, regulate soil temperature, suppress weed growth, and for aesthetics. They are applied to the soil surface, ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compost
Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical, and biological properties. It is commonly prepared by Decomposition, decomposing plant and food waste, recycling organic materials, and manure. The resulting mixture is rich in plant nutrients and beneficial organisms, such as bacteria, protozoa, nematodes, and fungi. Compost improves soil fertility in gardens, landscaping, horticulture, urban agriculture, and organic farming, reducing dependency on commercial chemical fertilizers. The benefits of compost include providing nutrients to crops as fertilizer, acting as a soil conditioner, increasing the humus or Humic acids, humic acid contents of the soil, and introducing beneficial microbes that help to suppress pathogens in the soil and reduce soil-borne diseases. At the simplest level, composting requires gathering a mix of green waste (nitrogen-rich materials such as leaves, grass, and food scraps) and brown waste (woody ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hotbed
A hotbed is a biological term for an area of decaying organic matter that is warmer than its surroundings. The heat gradient is generated by the decomposition of organic substituent within the pile by microorganism metabolization. A hotbed covered with a small glass cover (also called a hotbox) is used as a small version of a hothouse (heated greenhouse or cold frame). Oftentimes, this bed is made of manure from animals such as horses, which pass undigested plant cellulose Cellulose is an organic compound with the chemical formula, formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of glycosidic bond, β(1→4) linked glucose, D-glucose units. Cellulose is an important s ... in their droppings, creating a good environment for microorganisms to come and break down the cellulose and create a hotbed. (The digestive systems of ruminants such as cattle and sheep destroy and use all cellulose in their food, and their droppings remain col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cloche (agriculture)
In agriculture and gardening, a cloche (from French, ''cloche'' for "bell") is a covering for protecting plants from cold temperatures. The original form of a cloche is a bell-shaped glass cover that is placed over an individual plant; modern cloches are usually made from plastic. The use of cloches is traced back to market gardens in 19th century France, where entire fields of plants would be protected with cloches. In commercial growing, cloches have largely been replaced by row cover, and nowadays are mainly found in smaller gardens. History Paris, Parisian market gardens in the 1800s used 18-inch diameter bell-shaped glass jars (cloches) to protect plants in cold weather. They were used to protect everything from young seedlings to mature plants. Notched wooden sticks were used to prop up and vent the jars on sunny days, and were placed back down on the soil before nightfall. "Chase barn cloches", introduced in the early twentieth century by Major L.H. Chase, are construct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Frame
In agriculture and gardening, a cold frame is a transparent-roofed enclosure, built low to the ground, used to protect plants from adverse weather, primarily excessive cold or wet. The transparent top admits sunlight and prevents heat escape via convection that would otherwise occur, particularly at night. Essentially, a cold frame functions as a miniature greenhouse to extend the growing season. Historically, cold frames were built to be used in addition to a heated greenhouse. The name itself exemplifies the distinction between the warm greenhouse and the unheated cold frame. They were frequently built as part of the greenhouse's foundation brickwork along the southern wall (in northern latitudes). This allowed seeds to be germinated in the greenhouse and then easily moved to the attached cold frame to be "hardened-off" before final planting outside. Cold frames are similar to some enclosed hotbeds, also called hotboxes. The difference is in the amount of heat generated inside ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transpiration
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, changes osmotic pressure of cells, and enables mass flow of mineral nutrients. When water uptake by the roots is less than the water lost to the atmosphere by evaporation, plants close small pores called stomata to decrease water loss, which slows down nutrient uptake and decreases CO2 absorption from the atmosphere limiting metabolic processes, photosynthesis, and growth. Water and nutrient uptake Water is necessary for plants, but only a small amount of water taken up by the roots is used for growth and metabolism. The remaining 97–99.5% is lost by transpiration and guttation. Water with any dissolved mineral nutrients is absorbed into the roots by osmosis, which travels through the xylem by way of water molecule adhesion and coh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Row Cover
In agriculture and gardening, row cover is any transparent or semi-transparent flexible material, like fabric or plastic sheeting, used as a protective covering for plants, usually vegetables. Covers are used to extend growing seasons, and reduce undesirable effects of cold, wind and insects. Article marked reviewed by publisher in 2012. Row covers can reduce the drying effect of wind, and can provide a small amount of warming in a similar way to unheated cold frames, greenhouses and polytunnels, creating a microclimate for the plants. The first commercial-scale use of polyethylene row covers in the US was in the 1950s, and by the 1980s their use was widespread. Row cover is a lightweight synthetic, such as clear plastic (polyethylene) or spunbonded polyester called horticultural fleece. Plastic covers are elevated above plants on a supporting framework such as wire hoops to form a low tunnel. (Plastic placed directly on the ground is mulch.) Fleece covers can be placed di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate ester, carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, toughness, tough materials, and some grades are optically transparent. They are easily worked, injection molding, molded, and thermoforming, thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code, resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Structure Carbonate esters have planar OC(OC)2 cores, which confer rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Polycarbonates received their name because they are polymers containing carbonate ester, carbonate groups (−O−( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
