跳到主要內容

明天的農業會更好

明天的農業會更好
Advocates of 垂直農耕 say growing crops in urban high-rises will eventually be both greener and cheaper.
By OWEN FLETCHER

Want to see where your food might come from in the future? Look up.

The seeds of an agricultural revolution are taking root in cities around the world—a movement that boosters say will change the way that urbanites get their produce and solve some of the world's biggest environmental problems along the way.

It's called vertical farming, and it's based on one simple principle: Instead of trucking food from farms into cities, grow it as close to home as possible—in urban greenhouses that stretch upward instead of sprawling outward.

The idea is flowering in many forms. There's the 12-story triangular building going up in Sweden, where plants will travel on tracks from the top floor to the bottom to take advantage of sunlight and make harvesting easier. Then there's the onetime meatpacking plant in Chicago where vegetables are grown on floating rafts, nourished by waste from nearby fish tanks. And the farms dotted across the U.S. that hang their crops in the air, spraying the roots with nutrients, so they don't have to bring in soil or water tanks for the plants.

However vertical farming is implemented, advocates say the immediate benefits will be easy to see. There won't be as many delivery trucks guzzling fuel and belching out exhaust, and city dwellers will get easier access to fresh, healthy food.

Enlarge Image

Plantagon
Looking further, proponents say vertical farming could bring even bigger and more sweeping changes. Farming indoors could reduce the use of pesticides and herbicides, which pollute the environment in agricultural runoff. Preserving or reclaiming more natural ecosystems like forests could help slow climate change. And the more food we produce indoors, the less susceptible we are to environmental crises that disrupt crops and send prices skyrocketing, like the drought that devastated this year's U.S. corn crop.

Dickson Despommier, a microbiology professor at Columbia University who developed the idea of vertical farming with students in 1999, thinks vertical farming will become more and more attractive as climate change drives up the cost of conventional farming and technological advances make greenhouse farming cheaper. In fact, he hopes the world will be able to produce half of its food in vertical farms in 50 years.

Then "a significant portion of farmland could be abandoned," he says. "Ecosystem functions would rapidly improve, and the rate of global warming would slow down."

An Idea on the Rise
A host of vertical farms are up and running in the U.S. and overseas, and others are under construction. Some are backed by nonprofits aiming to promote environmental causes or local job creation. Others will be for-profit ventures meant to meet demand for local produce. And some, like one in South Korea, are being funded by governments looking for ways to boost domestic food security.

View Interactive

So far, vertical farms are producing only a small amount of food. Advocates are still developing different building designs and growing techniques to boost the efficiency of cultivating food indoors. And a proven business model based on the concept has yet to emerge.

One ambitious project under construction is trying to address all of those challenges at once. At 12 stories, the triangular farm in Linköping, Sweden, will be one of the tallest vertical farms in the world—most max out at several stories—and will use innovative ways to generate revenue. Not only will the company behind the farm, Sweden's Plantagon, sell its produce at a local farmer's market, but it also will lease out office space on most floors.

Another unique feature: Outside the office windows, on the building's southern face, a mechanical track enclosed in its own layer of glass will carry growing plants from the top of the building to the bottom floor. The arrangement is meant to give the plants even exposure to sunlight and allow Plantagon to perform all of its planting and harvesting in one place—on the ground floor. (After planting, a normal vertical elevator takes the boxed plants to the top floor to start their voyage down.) The company plans to produce 300 to 500 metric tons of leafy greens like bok choy a year.

Offsetting Costs
As for the price tag, "it's much more expensive, of course, to build a greenhouse vertical than to build a normal greenhouse," says Hans Hassle, Plantagon's chief executive. But the planned revenue streams will help make up for that, and energy costs will be lower because the setup will use waste from various sources—such as heat from a nearby power plant and biogas produced through conversion of the building's own organic garbage. All told, the planned energy-saving measures will reduce the building's energy use by at least 30% to 50%, Mr. Hassle says.

Mr. Hassle says the company's next greenhouse will be either a demonstration model in Shanghai or a research facility in Singapore. These are good venues for the idea, he says, because they're highly dense and urbanized societies that already need to produce more food locally.

In the U.S., vertical farms are sprouting in urban areas across the country, some in old buildings that have been repurposed for agriculture. One operation called the Plant is producing vegetables in a three-story former meatpacking facility on Chicago's South Side.

The farm grows vegetables on small rafts floating on water, which is filled with nutrients from waste produced by fish in a separate tank—a setup called aquaponics. Light comes from lamps designed to emit the proper wavelengths for plant growth. The Plant is also designing a growing system in which crops could grow sticking out at an upward angle from vertical boards, with nutrients provided to the plant roots by water dripping down a film from pipes near the ceiling.

The Plant was founded by John Edel, a 43-year-old Chicago native who has led other projects to renovate and reuse urban buildings. The facility currently rents out parts of its space to tenants including three farmers and two bakeries and plans to find more; it also intends to open a shared retail area where the tenants can sell their goods.

Enlarge Image

AeroFarms
GROW ANYWHERE This AeroFarms system is being used in buildings in Seattle, Chicago and elsewhere.

Other farms around the country use different techniques designed to save space, reduce water consumption and even avoid the need for soil. Farms in warehouses and other buildings in Seattle, Chicago, upstate New York and New Jersey, among other places, use an aeroponics system from AeroFarms of Ithaca, N.Y. The method involves growing plants with their roots hanging in the air, where they can be sprayed with water and nutrients.

Omega Garden Inc., of Qualicum Beach, British Columbia, sells a planting device called Volksgarden, a rotating cylinder four feet in diameter and two feet long. Plants grow in a circle around the inside of the cylinder. As the device rotates, their roots dip into a tray holding a liquid solution that provides water and nutrients. A light runs horizontally through the cylinder to nourish the crops.

Green Spirit Farms LLC is using the system in New Buffalo, Mich., in a former plastics-injection facility. The farm plans to fill the space with Volksgarden units stacked three levels high, says Green Spirit site manager Ben Wiggins.

Simpler Solutions?
Still, many agricultural experts aren't sold on the idea of vertical farming. The core argument against it: Conventional farms are the simplest and most efficient places to produce food. Growing food indoors, using artificial lights and other special equipment, means more effort and expense—and cancels out any benefits of being close to customers, critics say.

That's why George Monbiot, a writer and environmental activist based in Oxford, England, says there's "no prospect" that more complicated vertical-farming techniques could contribute substantially to world food production. As for those vertical farming systems that will consume extra energy to power equipment like artificial lights, he says, "Even if you are taking the energy from renewable sources, there are better ways of using that renewable energy."

Likewise, R. Ford Denison, an adjunct professor of agricultural ecology at the University of Minnesota, thinks the energy use from vertical farms would cancel out any fuel savings from transportation. "Food transport from farm to store is a tiny fraction of total agricultural energy use," he says. So if vertical farms use even small amounts of energy to run their systems, or if consumers have to use extra fuel traveling to urban farmers' markets, it "would swamp any energy savings in transporting food to the cities."

Backers say the comparison between conventional and vertical farming isn't apples to apples, since the government heavily subsidizes expenses including crop insurance for traditional agriculture, greatly reducing the costs involved and the risks that farmers face from unpredictable weather conditions.

Food Security
But boosters say the equation will very likely change as severe weather makes indoor farming a safer and more reliable alternative to regular growing. Not only will the rising cost of conventional farming make vertical farms look better in comparison, they say, but vertical farms in some places could end up getting subsidies.

"If we imagine that vertical farming is going to become part of a nation's food-security program, then naturally this part of the industry needs subsidies," Plantagon's Mr. Hassle says.

Dr. Despommier, who is also an adviser to Plantagon, acknowledges that energy use, particularly in artificial lighting, remains a challenge for some vertical farms. But he says the lighting industry has made significant progress in recent years on reducing power consumption for specialized lights to grow plants, and researchers continue to work on the problem.

More broadly, he argues that the idea of vertical farming on a large scale will seem increasingly realistic as techniques evolve. He cites cellphones and plasma-screen televisions as examples of innovations that were unimaginable before their time.

"You have to start small and you have to start at the research level before you jump into the commercial aspect of this thing, but that's the way all these ideas start," Dr. Despommier says. "Everything we have in this world of ours started out crazy."

The Readers Weigh In
Most WSJ.com readers in an online poll have expressed interest in buying local food. Here's a sampling of comments.

I can see how things are grown and made and how the animals are treated. Being knowledgeable about the food you eat is extremely important. Ignorance is no longer bliss when it comes to what goes into your food.

-- Scargosun

The locavore movement isn't just about getting food that is fresher, but also about supporting the local economy. It is "worth it" to keep our dollars and jobs within our community.

-- Carolyn Pearce

The long-term benefits for our environment, local economies and health far outweigh the expense and inconvenience. If more people start buying local then the cost will decline.

-- Ben Schaub

Mr. Fletcher is a staff reporter in The Wall Street Journal's Chicago bureau. He can be reached at owen.fletcher@wsj.com.

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…

蝶豆花

蝶豆花 原產拉丁美洲的蝶豆花是一種典型的熱帶蔓藤植物,全年盛開。
butterfly pea,拉丁語叫:Clitoria ternatea,泰語叫Dok Anchan
中文名叫蝶豆花,藍蝶花,藍蝴蝶、蝴蝶藍花,還有蝴羊豆、豆碧等別名。
用蝶豆花當作高品位浪漫的茶品飲用、以及當作天然食品色素制作糕點是拉丁美洲和南洋國家的風情和習俗。
蝶豆花的味道自然甘甜,南洋國家的一些五星級酒店通常把蝶豆花茶當作高貴的迎賓茶來接待貴賓。
營養價值 蝶豆花具有豐富的維他命A,C和E, 而且可以提高免疫力, 幫助和促進皮膚的彈力和骨膠原, 同時還具有補腦,促進腦的活力,防止胃痛,抗憂郁、抗壓力、鎮靜、止驚厥、緩和情緒等天然保健功效。
蝶豆花中的天然藍色素,也是有療效的。如果將其加入檸檬並調制成花茶飲品,就是保健心臟血管的絕佳飲料。
食用價值 蝶豆花的可食部位是葉、花及嫩莢。較幼嫩的葉片及盛開的花朵,亦可拿來煮湯、油炸等。用嫩芽來炒肉絲或煮熟後食用,都十分可口。蝶豆花的葉及花的萃取液,可當作純天然的食品染料。

直達香草(herb4kitchen)
PS.營業用批量報價

錦鯉養殖基本知識

◎飼養與管理的重點 只要不是劇烈的變化,錦鯉很容易適應各水溫水質等環境的變化。並不是沒有大庭園就無法飼養,有人甚至在二樓陽台或頂樓陽台造水池飼養。然而我們是欣賞錦鯉雄壯豪邁之氣,因此水池盡量寬闊為宜,以水深1.2m以上為理想。魚池必須有底水排出,過濾循環等設備。用水不一定要取地下水,自來水也可以飼養。
<因為都市中有景觀安全的需求,及屋頂花園有荷重的需求,錦鯉池水深可以低到30cm左右。>
◎每天排水
A、糞或枯死的藻類全部送至過濾槽的話,耗氧量會增大,pH就下降,更會轉變為亞硝酸,增了過濾槽的負擔。為了盡量減輕過濾槽的負擔,每天至少把魚池的底水排水使固物排出去,把中間水送去沉澱槽及過濾槽。 
B、把固體廢物的魚糞集中排出,最好不要從池底打氣而是從排糞口的上方40~50公分打打氣。如此氣泡往上昇。池水產生對流。污物就集中於排糞口。
<可以設計水流把固體廢物盡量集中或排出到過濾系統中。>
◎過濾槽管理
A、細菌附著於濾材,分解固體廢物會消耗大量的氧。 
B、溶氧不足時,厭氧菌會把硝酸還原亞硝酸,或從碳酸氣發生沼氣,也會從硫酸分解產生硫化氫等有毒氣體。
<如果溶氧不足,可以優先把打氣設備放置到生化過濾槽中。>
◎溶氧要充份
A、水中溶氧不足的話,會影響錦鯉的生育,飼料的消化,,水質的維持等等。
B、硝酸,亞硝酸的濃度增高時,會影響溶氧量。所以優先去除硝酸及亞硝酸。
C、使用沸石可輕易去除硝酸,沸石量約等重於魚體總重量。
<沸石再生法,是將沸石浸泡25℃以上1:10食鹽水數小時,再以清水洗淨即可。>
◎水質的控制
水質硬度高的話,錦鯉肌膚經常會有少許充血的狀態。豔麗性也會慢慢消失,紅緋會上升。pH值低,肌膚變的很不好看,但是雖餵增色飼料,依然不見起色,徒增浪費。pH值7.1~7.5最適宜的。
◎鯉餌的重要性
良好的魚餌不會崩壞鯉的體型。餌的量也是在夏天水溫 高的時候,訂定停餌期間,才是整體來說使鯉變胖最重要的秘訣。如果還是想 要給很多餌的話,要增加循還量。錦鯉在水溫超過28度的時候,應給與相當於 鯉全體重量3%的餌。水溫25度時1.5%,水溫20度時0.3%,16度以下則要停止鯉餌,這就是鯉魚長得強壯的要訣。連續不斷地給鯉餌的話,引起內臟障礙, 而影響到鯉不會長壯,甚至導至體型的變歪。
◎魚病預防
水的管理與定期消毒都是很重要的步驟,…