跳到主要內容

綠化的一角來養魚

Fish Farms, With a Side of Greens

綠色的一角來養魚

Jeff Redmon 報導
Sweet Water Organics, a company in Milwaukee, raises perch and grows leafy green vegetables in a former factory.
Sweet Water Organics, Genevieve Roberts攝影
Aquaponics-a combination of aquaculture, or fish cultivation, and hydroponics, or water-based planting -utilizes a symbiotic relationship between fish and plants. Fish waste provides nutrients for the plants, which in turn filter the water in which the fish live. Cuttings from plant are composted to create food for worms, which provide food for the fish, completing the cycle.
“Aquaponics is a method of delivering multiple crops with minimum input, through a closed-loop method of farming,” said Charlie Price, founder of Aquaponics UK, the nonprofit organization that runs the farm.
A kilogram, or 2.2 pounds, of fish food, produces at least 50 kilograms of vegetables and 0.8 kilogram of fish, he said. “As the ecosystem becomes self-sustainable, the fish food comes from the worms, so the entire cycle is free.”
Mr. Price’s organization is working internationally with food production projects in India, Afghanistan and several African countries, including Uganda, Kenya and Namibia. But it also works closer to home. Its next project is a city farm shop in London at which people will be able to pick their own salads and choose fish for their supper from giant tanks.
The store, called Farm:shop, in the Borough of Hackney, was created by Something & Son, a design company, working with the local council. It hopes to make direct links between the city neighborhood and the realities of farming. A location has been secured, and the project is in the late stages of acquiring funding.
The potential for urban farming is being explored in Milwaukee, where some of the leading aquaponics entrepreneurs are based. Sweet Water Organics, an urban aquaponics company, raises perch and leafy green vegetables in an old factory that housed a mining company until the 1950s. The farm, founded by James Godsil and Josh Fraundorf in January 2009, has sold thousands of fish and produces about 70 kilograms of vegetables a week. It is expanding rapidly, and plans to produce between 360 and 450 kilograms of greens a week and to grow tens of thousands of kilograms of perch in coming years.
Mr. Godsil and Mr. Fraundorf learned the techniques largely from Will Allen, an urban farmer and winner of a MacArthur “genius” fellowship, and through trial and error.
“We believe this is the world’s first effort to turn a factory into a fish and vegetable farm, and it’s a complex proposition,” Mr. Godsil said. “We’ve experimented with 40 types of lettuce, settled on three or four, and we’re now trialing spinach.”
The farm started with a $50,000 investment but has attracted about $1 million in funds over the past 20 months and partnerships with the Milwaukee School of Engineering and informally with the University of Stirling in Scotland. It is discussing the prospect of a $30 million concept for Sweetwater villages, which would have community-scale manufacturing, restaurants and cafes with food produced from aquaponics.
The farm is receiving support from the University of Wisconsin and Sea Grants, a U.S. government program, to grow yellow perch and possibly blue gill, species indigenous to the Great Lakes but in decline. “The fish it produces are a 21st century form of protein that won’t harm planet earth,” Mr. Godsil said.
Industrial aquaponics is still in its infancy, with only five facilities of more than 0.4 hectare, or one acre, operating in the world, although interest is growing, particularly in areas with water shortages. Aquaponics use between 80 and 90 per cent less water than traditional growing methods.
In Barbados, where fresh water is scarce and 80 per cent of food is imported, according to the Inter-American Institute for Cooperation on Agriculture, a project known as “Aquaponic island” started last year, with a goal of educating farmers about the benefits of aquaponics to make it their technology of choice in four years. The project has funding from the United Nations Development Program, the Barbadian Ministry of Agriculture, the institute and a community group, the Baird's Village Aquaponics Association. A commercial-scale system was set up at Baird’s Village, and this year aquaponic systems are being introduced to many of the island's schools.
In Australia, where farmers have struggled with drought for the past decade, backyard aquaponic systems have grown in popularity. Joel Malcolm, who opened the world’s first aquaponics retail store, Backyard Aquaponics, in the Australian city of Perth, sells about 300 systems a year.
“With water restrictions enforced in almost every city around the country, people just can’t have their traditional vegetable garden,” he said. “Being able to produce your own chemical-free fish and vegetables in your own backyard not only saves money but also provides enjoyment and satisfaction. Lately there have been quite a few schools installing systems here as learning tools for the kids.”
While backyard systems are in their infancy in the United States, they are growing in popularity, with estimates that there may be 800 to 1,200 aquaponics setups in American homes and yards and as many as 1,000 more in schools, according to the Aquaponics Journal.
Could this almost-waste-free food production method be the miracle solution to tackle worldwide food shortages that some expect? Brett Roe, who investigated ecologically integrated production systems at the University of Queensland in Australia, cautioned that it might not be a cure-all. “Aquaponics offers decentralized food security on a small scale, and reuse of resources,” he said. “Every little bit helps. But in developing countries it may make better sense to culture fish in ponds and use the wastewater on land-based crops; a simple linkage of aquaculture and crop farming that has the same general effect of reusing resources and can be practiced in a larger scale of economy.”
While still in its fledgling stages, Mr. Godsil said the potential of aquaponics was “breathtaking.”
“Aquaponics has inspired pragmatic utopian visions, that keep getting validated by the facts. We need solutions to what could be a Pearl Harbor moment for the species, if global warming trends continue the way Al Gore and scientists predict,” he said referring to the former U.S. vice president.
Mr. Price of Aquaponics UK said: “Given our requirements to provide significantly more energy and food in the next 20 years, aquaponics can play a vital role. It isn’t a new technology – in fact it was first documented by the Aztecs-but when adopted in our new climate it provides a highly profitable and sustainable food production system.”

留言

這個網誌中的熱門文章

蔬菜對溫度日照條件的要求

蔬菜對溫度日照條件的要求
全日照  8個小時日照 瓜類、茄果類、豆類、山藥、豆薯(地瓜)。番茄、黃瓜、茄子、辣椒等喜溫中、強光性
蔬菜夏秋季生產,玉米、青椒、西瓜、南瓜、西紅柿、茄子、芝麻、向日葵類。
其次是根莖類,如:馬鈴薯、甜菜、胡蘿蔔、白蘿蔔、甘藷、山藥等等。至少需半日照,才能生長,芋頭雖喜歡全日照,但比其他蔬菜耐蔭。 
需要中等光照大白菜、甘藍、芥菜、蒜、洋蔥。 

長日性蔬菜白菜、甘藍、芥菜、蘿蔔、胡蘿蔔、芹菜、菠菜、萵苣、蠶豆、豌豆、大蔥、洋蔥。

短日性蔬菜豇豆、扁豆、莧菜、空心菜。         

中光性蔬菜黃瓜、番茄、茄子、辣椒、菜豆

菜豆

菜豆喜溫暖,不耐高溫和霜凍。菜豆種子發芽的適溫為20-30℃;在40℃以上的高溫和10℃以下的低溫,種子不易發芽。幼苗生長適宜氣溫為18-25℃。花芽分化的適宜氣溫為20-25℃,過高或過低溫度易出現發育不完全的花蕾、落花。

菜豆對光照強度的要求較高。在適宜溫度條件下,光照充足則植株生長健壯,莖的節間短而分枝多,開花結莢比較多,而且有利於根部對磷肥的吸收。當光照強度減弱時,植株易徒長,莖的節間長,分枝少,葉質薄,而且開花結莢數少,易落花落莢。

菜豆根系強大,能耐一定程度乾旱,但喜中度濕潤土壤條件,要求水分供應適中,不耐澇。生長期適宜土壤濕度為田間最大持水量的60%-70%,空氣相對濕度以80%為宜。開花結莢期對水分最敏感,此期土壤乾旱對開花結莢有不良影響,開花數、結莢數及莢內種子數減少。土壤水分過大時,下部葉片黃化,早脫落。空氣濕度過大會引起徒長、結莢不良。

菜豆具有深根性和根瘤菌,對土壤的要求不甚嚴格,但仍以土層深厚肥沃、排水良好的輕砂壤土或粘質壤土為好。土壤過於粘重、低溫、排水和通氣不良則生長不良,炭疽病重。菜豆喜中性至微酸性土壤,適宜的土壤pH為5-7.0,其中以州6.2-6.8最適宜。菜豆最忌連作,生產中應實行2-3年輪作。

菜豆生育過程中,主要吸收鉀和氮較多,還要吸收一定量的磷和鈣,才能良好發育。結莢期吸收磷鉀量較大。磷鉀肥對菜豆植株的生長發育、根瘤菌的發育、花芽分化、開花結莢和種子的發育等均有影響。缺乏磷肥,菜豆嫩莢和種子的品質和產量就會降低。缺鈣,幼葉葉片捲曲,葉緣失綠和生長點死亡。缺硼,則根係不發達,影響根瘤菌固氮,使花和豆莢發育不良。 耐陰半陰(大概3-4小時日照) 應選擇耐陰的蔬菜種植,如萵…

黑檸檬

黑檸檬
Dried lemons are actually limes and are used heavily in Persian Gulf and also Iranian cuisine where they add a strong bitter flavor in addition to sourness. They are made by boiling ripe limes in salt water, and then sun drying until the insides turn black. The outside color varies from tan to black. They are sold whole or ground.

Black Lime is a spice used in Middle Eastern dishes. It is made by boiling fresh lime in salt water and sun drying until the insides turn black. The outside color varies from tan to black. It is sold whole or ground.

黑檸檬實際上是使用萊姆,並且在波斯灣和伊朗料理中被大量使用,除了酸味外,它們還添加了強烈的苦味。它們是利用鹽水煮成熟萊姆,然後曬乾,直到內部變黑。外部顏色從棕褐色變化到黑色。他們可以整顆或切片販售。
黑檸檬是用於中東菜餚的香料。它是通過在鹽水中煮沸新鮮的檸檬並經天然乾燥,直到內部變黑。外觀從棕褐色變成黑色。
USE Black limes are usually used in legume, seafood or meat dishes. They are pierced, peeled or crushed before adding them to the dish. After cooking they become softer and edible. They can also be powdered and added to rice dishes. Powdered black lime is also used as an ingredient in Gulf-…

為何冰箱冷凍室非得是零下18度?

為何冰箱冷凍室非得是零下18度? 不少家庭的冰箱有led面板,可顯示冷藏室和冷凍室溫度。每次看到那個零下18℃,不少人,包括筆者在內就會禁不住提出一個小疑問:為什麼冷凍室溫度非得是零下18℃?最多零下1℃不就結冰了嗎?搞這麼低溫度實在是浪費電呢。

聰明如很多人是這樣推測的

百思不得其解,於是很多人,包括筆者在內就開始推測後面的機制了。冷凍室的零下18℃其實不費電,相反,它是節約電力的一個好措施。為何?

冰箱隔一段時間,內部溫度升高後,它就要啟動壓縮機,嗡嗡嗡的。頻繁啟動壓縮機不僅耗電,冰箱的壽命也會降低,還有就是很吵人。怎麼辦?簡單,先把冷凍室的溫度搞得低低的,比如零下18℃左右。


然後,冷凍室的冷氣往上走,來到冷藏室,如此,就能長時間保持冷藏室的溫度處於0到8℃以內了。

待冷凍室的冷氣散失過多,溫度升高到零下幾度時,再啟動冰箱的壓縮機把溫度再次降到零下18℃,如此,冰箱的啟動次數就變少了。

實際是這樣嗎?很遺憾,不是。

原因之一:不一樣的水

水到零度以下就結冰了,這是絕大多數人的認識。然而仔細一想,這不適用於冰箱的冷凍室。因為冷凍室存放的不是上百升礦泉水,而是各種各樣的食物。

食物中含有大量水這沒錯,但這些水同時含有大量的鹽、糖等物質。就像每1升海水中大約含有35克鹽,所以平均起來,要到零下1.33℃時海水才會結冰。

因此,要想把食物凍結,並不是溫度只要達到水的冰點就可以,得保證足夠低的溫度,食物中的水才能凍結,這很重要,因為食物中只要有液態水存在,這就等於是為各種細菌的繁殖提供了必備條件。

圖為牛肉薄片在不同溫度和不同時間內測得的牛肉中凍結水量的曲線。

當牛肉薄片的溫度為零下4℃時,只有70%的水分被凍結;溫度下降到零下9℃左右時,也還有3%的水分未凍結;即使牛肉薄片的溫度降低到零下18℃時,也不是100%的水分都被凍結住。

原因之二:嗜冷微生物

根據微生物對不同溫度的適應範圍,可將微生物分為三大類,嗜熱菌、嗜溫菌和嗜冷菌。在食物的冷藏和冷凍過程中,我們面對的「敵人」是嗜溫菌和嗜冷菌。

一般來說,能引起食物腐敗和食物致毒的嗜溫菌,在低於3 ℃情況下不產生毒素,當然,個別菌種例外。

而對於嗜冷菌,一般得在零下10 ℃到零下12 ℃時才會停止生長。

有的黴菌甚至要到零下15~零下18 ℃時才會停止生長。

瞧,我們以為,零下幾攝氏度後微生物就被殺死或停止繁殖了,但…