Isabella Tree runs Knepp Castle Estate with her husband, the conservationist Charlie Burrell, and is the author of Wilding: The Return of Nature to a British Farm.

Isabella Tree與她夫婿，同時也是保育學家的Charlie Burrell，共同經營Knepp Castle Estate。這塊地過去原本用於高強度農業，現在正朝向環境復育與再野生化之再造過程。她也是《野生化：將自然帶回英國農地》（Wilding: The Return of Nature to a British Farm）這本書的作者。

Veganism has rocketed in the UK over the past couple of years – from an estimated half a million people in 2016 to more than 3.5 million – 5% of our population – today. Influential documentaries such as Cowspiracy and What the Health have thrown a spotlight on the intensive meat and dairy industry, exposing the impacts on animal and human health and the wider environment.

在過去兩年，素食主義在英國境內迅速成長：素食人口從2016年的約50萬人成長到今日的350萬人，這佔了我國人口的百分之五。具有影響力的紀錄片如《陰牛論》（Cowspiracy）與《什麼鬼健康》（What the Health）將焦點投射到了高強度畜牧業與酪農業上，揭露了這些產業對動物與人類以及自然環境的衝擊。

Rather than being seduced by exhortations to eat more products made from industrially grown soya, maize and grains, we should be encouraging sustainable forms of meat and dairy production based on traditional rotational systems, permanent pasture and conservation grazing. We should, at the very least, question the ethics of driving up demand for crops that require high inputs of fertiliser, fungicides, pesticides and herbicides, while demonising sustainable forms of livestock farming that can restore soils and biodiversity, and sequester carbon.

與其因為看了這麼多告誡而轉往吃更由工業化栽種的黃豆、玉米、穀類製品，我們應該鼓勵採用傳統餵食系統、常在性放牧場與保育邢牧草的永續性畜牧業與酪農業之產品。提高了人們對需要極高肥料、殺真菌劑、殺蟲劑、除草劑用量之作物的需求，同時卻妖魔化了能夠復育土壤與生物多樣性以及碳截存的永續性畜牧業，我們至少應該對這雙重標準背後的道德提出疑問。

In 2000, my husband and I turned our 1,400-hectare (3,500-acre) farm in West Sussex over to extensive grazing using free-roaming herds of old English longhorn cattle, Tamworth pigs, Exmoor ponies, and red and fallow deer as part of a rewilding project. For 17 years, we had struggled to make our conventional arable and dairy business profitable, but on heavy Low Weald clay, we could never compete with farms on lighter soils. The decision turned our fortunes around. Now, eco-tourism, rental of post-agricultural buildings, and 75 tonnes a year of organic, pasture-fed meat contribute to a profitable business. And since the animals live outside all year round, with plenty to eat, they do not require supplementary feeding and rarely need to see the vet.

2000年的時候，作為野生環境復育計畫的一部分，我們夫妻倆將我們在西薩西克斯的1400公頃（3500英畝）的農地轉為廣大的牧場，上面放牧著一批批的老英格蘭長角牛、泰姆華斯豬、埃克斯摩小馬、赤鹿與黇鹿。17年來，我們與生活奮戰，讓我們的傳統耕地和乳製品獲益，不過在低地威爾德黏質土上，我們永遠無法與輕質土壤上的農地競爭。這個抉擇讓我們轉運了。現在生態旅遊、出租後農業農舍，以及每年75公噸的牧草有機肉類讓我們經營獲益。而且，這些動物全年住在我們四周，有著許多的食物，因此他們無須額外的營養補品餵食，也很少看獸醫。

The animals live in natural herds and wander wherever they please. They wallow in streams and water-meadows. They rest where they like (they disdain the open barns left for them as shelter) and eat what they like. The cattle and deer graze on wildflowers and grasses but they also browse among shrubs and trees. The pigs rootle for rhizomes and even dive for swan mussels in ponds. The way they graze, puddle and trample stimulates vegetation in different ways, which in turn creates opportunities for other species, including small mammals and birds.

跟著自然群體居住的動物們可以隨他們高興四處跑。他們在小溪和水草中打滾。他們在他們喜歡的地方休息（他們反而鄙棄了給他們當遮蔽用的開放式棚廄）並吃著他們喜歡的東西。牛群與鹿隻在野花和草上進食，也會在矮樹叢和樹林間覓食。豬隻則用鼻子搜索挖掘根莖類，甚至到池子裡潛水找淡菜吃。他們吃草、嬉戲、踩踏，反而刺激了植生，進而給其他物種製造了生機，包括了小型哺乳類與鳥類。

Crucially, because we don't dose them with avermectins (the anti-worming agents routinely fed to livestock in intensive systems) or antibiotics, their dung feeds earthworms, bacteria, fungi and invertebrates such as dung beetles, which pull the manure down into the earth. This is a vital process of ecosystem restoration, returning nutrients and structure to the soil. Soil loss is one of the greatest catastrophes facing the world today. A 2015 report from the UN Food and Agriculture Organization states that, globally, 25 to 40bn tonnes of topsoil are lost annually to erosion, thanks mainly to ploughing and intensive cropping. In the UK, topsoil depletion is so severe that in 2014 the trade magazine Farmers Weekly announced we may have only 100 harvests left. Letting arable land lie fallow and returning it to grazed pasture for a period – as farmers used to, before artificial fertilisers and mechanisation made continuous cropping possible – is the only way to reverse that process, halt erosion and rebuild soil, according to the UN Food and Agriculture Organisation. The grazing livestock not only provide farmers with an income, but the animals' dung, urine and even the way they graze, accelerates soil restoration. The key is to be organic, and keep livestock numbers low to prevent over-grazing.

最關鍵的是：我們都沒有使用任何的阿維菌素（一種抗寄生蟲劑，一般高強度畜牧業會餵給牲畜食用）或抗生素，因此他們的糞便可以做為蚯蚓、細菌、真菌類的養分，當然還有糞金龜也受益良多，而且他們這類無脊椎動物還會把糞土帶到土中。這是生態系復育過程中很重要的一環，因為這過程將養分與結構帶回了土壤中。土壤流失是當今世界上最嚴重的災難之一。一份2015年的聯合國糧農組織報告指出全球每年有250到400百億頓表土因土壤侵蝕而流失，而其中最主要的原因都是高密度農作所造成的。在英國，表土侵蝕嚴重到2014年有一期的《農夫周刊》宣布我們的土壤可能只能再撐個100收。讓農地休耕並使之回歸生長牧草一段時間 ──這也是過去農夫常用的方法，直到人工肥料與機械化實現了連續性耕作為止── 是唯一能夠反轉土壤侵蝕的方式，並重建土壤。

Twenty years ago, our soils at the farm – severely degraded after decades of ploughing and chemical inputs – were almost biologically dead. Now, we have fruiting fungi and orchids appearing in our former arable fields: an indication that subterranean networks of mycorrhizal fungi are spreading. We have 19 types of earthworm – keystone species responsible for aerating, rotavating, fertilising, hydrating, and even detoxifying the soil. We've found 23 species of dung beetle in a single cowpat, one of which – the violet dor beetle – hasn't been seen in Sussex for 50 years. Birds that feed on insects attracted by this nutritious dung are rocketing. The rootling of the pigs provides opportunities for native flora and shrubs to germinate, including sallow, and this has given rise to the biggest colony of purple emperors in Britain, one of our rarest butterflies, which lays its eggs on sallow leaves.

20年前，我們田裡的土壤因為數十年以來的耕作與化學藥劑的注入而重度劣化，幾乎可宣告"死亡"。現在，我們有許多的菌類植物與蘭花出現在我們過去的耕地上，顯示了地底下的菌根菌網絡正逐漸擴散開來。我們有19種蚯蚓：他們是關鍵物種，負責土壤的曝氣、攪動、沃化、增加水含量，甚至解毒。我們在一團牛糞中就發現了23種糞金龜，而其中一種為紫羅蘭金龜，在薩西克斯已經有50年沒有被人看到了。被這些受糞屎所吸引的蟲子又提供了鳥類營養，使得鳥類族群也急速增加。豬隻用鼻子挖掘土類找食物的過程，也為原生植物群和矮樹叢能夠發芽、成長，其中包括了闊葉柳，使得產卵於其葉面的「布列顛紫皇帝」紫閃蛺蝶這種罕見的蝴蝶聚落大為成長。

Not only does this system of natural grazing aid the environment in terms of soil restoration, biodiversity, pollinating insects, water quality, and flood mitigation – but it also it guarantees healthy lives for the animals, and they in turn produce meat that is healthy for us. In direct contrast to grain-fed and grain-finished meat from intensive systems, wholly pasture-fed meat is high in beta carotene, calcium, selenium, magnesium, potassium, as well as vitamins E and B, and conjugated linoleic acid (CLA) – a powerful anti-carcinogen. It is also high in the long-chain omega-3 fatty acid DHA, which is vital for human brain development but extremely difficult for vegans to obtain.

這種天然牧草系統不但在土壤復育、生物多樣性、授粉昆蟲、水質、洪患緩和上協助了自然環境，也為動物保障了一個健康的生活，進而為我們提供了健康的肉類。完全相對於那些高強度畜產業中以穀類飼料進食的牲畜所產出的肉類，全牧草進食牲畜所產出的肉類具有高含量的β胡蘿蔔素、鈣質、硒、鎂、鉀，以及維他命E、維他命B、共軛亞麻油酸（一種強力抗癌劑），同時也包含有高含量的長鏈Omega-3脂肪酸DHA，對於人類腦部發展極為重要卻難以從素食中攝取。

Much has been made of the methane emissions of livestock, but these are lower in biodiverse pasture systems that include wild plants such as angelica, common fumitory, shepherd's purse, and bird's-foot trefoil because they contain fumaric acid – a compound that, when added to the diet of lambs at the Rowett Institute in Aberdeen, reduced emissions of methane by 70%.

雖然牲畜會排放大量的甲烷，但在牧草系統的牲畜排放的量相對較小，因為野生植物如白芷（當歸）、球果紫菫、薺菜、百脈根含有紫堇酸（反丁烯二酸）。根據亞伯丁羅維特研究所的實驗，若在小羊的飲食中加入紫堇酸，能夠降低七成的甲烷排放量。

In the vegan equation, by contrast, the carbon cost of ploughing is rarely considered. Since the industrial revolution, according to a 2017 report in the science journal Nature, up to 70% of the carbon in our cultivated soils has been lost to the atmosphere.

對於素食，很少有人會思考農耕的碳足跡。根據一份2017年《自然期刊》上的報告，自從工業革命以來，農耕土壤損耗了七成的碳，而這些碳則被排到了大氣中。

So, there's a huge responsibility here: unless you're sourcing your vegan products specifically from organic, "no-dig" systems, you are actively participating in the destruction of soil biota, promoting a system that deprives other species, including small mammals, birds and reptiles, of the conditions for life, and significantly contributing to climate change.

所以吃素也有很大的責任：除非你吃的是以傳統方式耕作的有機素食產品、「非挖掘」系統，否則你也是個主動參與了土壤生物群的毀滅幫兇，並促進了一個剝奪其他生物的生存之系統，受影響的不只有小型哺乳類、鳥類、爬蟲類，更劇烈地為氣候變遷貢獻許多。

Our ecology evolved with large herbivores – with free-roaming herds of aurochs (the ancestral cow), tarpan (the original horse), elk, bear, bison, red deer, roe deer, wild boar, and millions of beavers. They are species whose interactions with the environment sustain and promote life. Using herbivores as part of the farming cycle can go a long way towards making agriculture sustainable.

我們的生態系是隨著大型草食動物演化的，包括了自由漫遊於大地的歐洲原牛、歐洲野馬、駝鹿、熊、紅鹿、歐洲狍、野豬，以及數百萬隻的河狸。他們都是與環境永續性互動並促進生命循環的物種。使用草食性動物作為農業循環的一部分能夠走得更長久，讓農業達到永續性。（編按：野豬不是草食性，而是雜食性的動物。）

There's no question we should all be eating far less meat, and calls for an end to high-carbon, polluting, unethical, intensive forms of grain-fed meat production are commendable. But if your concerns as a vegan are the environment, animal welfare and your own health, then it's no longer possible to pretend that these are all met simply by giving up meat and dairy. Counterintuitive as it may seem, adding the occasional organic, pasture-fed steak to your diet could be the right way to square the circle.

毫無疑問的，我們應該少吃點肉，且呼籲終結高碳排又汙染且不道德的高強度餵穀肉類產品是值得稱許的。不過，如果你認為吃素就很環保、對動物好、對健康好，那麼就別在假裝不吃肉類與乳製品就可以全部達標上述目的。看起來好像很違背直覺，不過在飲食中加點偶爾有機的食草牛排可能才是正確的做法。