If you were to place all the rice consumed each year on one side of a scale, and every person in the world on the other, the scale would tip heavily towards rice's favor. This beloved crop contributes over 20% of the calories consumed by humans each year. Korean bibimbap, Nigerian jollof, Indian biryani, Spanish paella, and countless other culinary masterpieces all begin with rice. So how did this humble grain end up in so many cuisines?
如果你将每年消费的大米量 放在天平的一侧, 将世界上的人口放在另一边, 那么天平就会大大偏向于大米一侧。 这种备受喜爱的作物贡献了人类 每年消耗的卡路里的 20 %以上。 韩式石锅拌饭、尼日利亚加罗夫饭、 印度香饭、西班牙海鲜饭 和无数其他烹饪杰作都有米饭的身影。 那么,这种不起眼的谷物是 如何融入这么多美食中的呢?
The roots of rice go back thousands of years to when early farmers in Asia, Africa, and South America each independently domesticated the crop. First came Asian rice, which many plant geneticists believe originated in what's now China. Over 10,000 years ago, nomadic hunters in the region began gathering and eating seeds from a weedy grass. Then, around 9,000 years ago, they started planting these seeds, prompting nomadic hunters to settle into farming communities. With each harvest, growers selected and replanted seeds from the rice plants that pleased them most— like those with bigger and more plentiful grains or aromatic flavors. Over millennia, thousands of varieties of Asian rice emerged.
水稻的起源可以追溯到几千年前 亚洲、非洲和南美的早期农民 各自独立驯化水稻的时候。 首先是亚洲大米, 许多植物遗传学家认为 它起源于现在的中国。 一万多年前,该地区的游牧猎人 开始从杂草丛中采集和食用种子。 然后,大约在 9,000 年前, 他们开始播种这些种子, 促使游牧猎人定居在农业社区。 每次收获时,种植者都会从最令他们 满意的水稻中挑选并重新种植种子, 例如谷物更,更丰富 或具有芳香味的种子。 几千年来,出现了数千种亚洲大米。
A relative of the same weedy grass was also domesticated in Africa around 3,000 years ago. Today, its growth is mostly limited to West Africa. South American growers also domesticated rice around 4,000 years ago, though the crop was lost after the arrival of Europeans.
大约在 3000 年前, 非洲也驯化了 同样的杂草的亲属。 如今,其增长主要局限于西非。 南美的种植者也在 大约 4000 年前驯化了水稻, 但欧洲人到来后收成就流失了。
Asian rice, however, spread widely, and is now a cornerstone of diet and culture in Asia and beyond. In India and Nepal, many Hindus mark an infant's transition to solid foods with a ceremony known as Annaprashan, where the baby tastes rice for the first time. in Japan, rice is so central to diets that the word "gohan" means both "cooked rice" and "meal."
但是,亚洲大米传播广泛, 现在已成为亚洲及其他地区 饮食和文化的基石。 在印度和尼泊尔,许多印度教徒会 纪念婴儿转为进食固体食物, 这种仪式名为安纳普拉尚。 也就是婴儿第一次品尝大米。 在日本,大米是饮食的核心 , “悟饭”一词 意味着 “煮熟的米饭” 和 “膳食”。
The global expansion of rice cultivation was only possible because the plant can grow in many climates— from tropical to temperate. As a semi-aquatic plant, rice happily grows in submerged soils. Many other crops can't survive in standing water because their root cells rely on air within soil to access oxygen. But rice plants have air channels in their roots that allow oxygen to travel from the leaves and stems to the submerged tissues. Traditionally, growers plant rice in paddy fields— flat land submerged under as much as 10 centimeters of water throughout the growing season. This practice returns high yields since many competing weeds can't hack it in the aquatic environment. But the technique is also water intensive. Rice covers 11% of global cropland, but uses over a third of the world's irrigation water.
水稻种植的全球扩张之所以成为可能, 是因为该植物可以 在许多气候中生长—— 从热带到温带。 作为一种半水生植物, 水稻在水下的土壤中生长活跃。 许多其他作物无法在积水中生存, 因为它们的根细胞依赖 土壤中的空气来获取氧气。 但是水稻植物的根部有气腔,允许氧气 从叶子和茎传播到水下组织。 传统上,种植者在稻田里种植水稻—— 整个生长季节, 水深可达 10 厘米的平地。 这种方式非常高产, 因为许多相互竞争的杂草 无法在水生环境中影响水稻。 但是该技术也需要大量用水。 水稻覆盖了全球农田的 11 %, 但使用了世界三分之一 以上的灌溉用水。
This form of rice production also pumps out a surprising amount of greenhouse gas emissions. Flooded fields are the perfect breeding grounds for microorganisms known as methanogens. These microscopic lifeforms thrive in environments lacking oxygen, because they evolved when the Earth contained little of this gas. Methanogens are the only organisms known to produce methane— a greenhouse gas 25 times more potent than carbon dioxide at trapping heat in the atmosphere. Cows, for example, are infamous for burping out methane due to methanogens in their stomachs. In a flooded paddy field, methanogens set to work eating away at organic material in the submerged soil and multiplying rapidly, all the while releasing copious amounts of methane. The result: rice cultivation contributes around 12% of human-caused methane emissions each year.
这种形式的大米生产还排放出 惊人的温室气体排放。 被洪水淹没的田地是甲烷原微生物的 理想繁殖地。 这些微小生命体在 缺乏氧气的环境中茁壮成长, 因为它们是在地球几乎 不含氧气时进化的。 甲烷原是已知唯一能产生甲烷的生物, 甲烷是一种温室气体, 在大气中产生热量的能力 是二氧化碳的25倍。 例如,奶牛的差评就是因其胃中 有能排除甲烷的甲烷原。 在被洪水淹没的稻田里, 甲烷原会吞噬水下土壤中的有机物质 并迅速繁殖, 同时释放出大量的甲烷, 结果:每年水稻种植排放量约占 人为甲烷排放量的 12%。
But there's good news. Rice doesn't actually need to grow in continuously flooded paddies. Researchers and growers are exploring water management strategies that can cut the methane while keeping the yield. One promising technique is known as alternate wetting and drying. Growers periodically let the water level drop, which keeps methanogen growth in check. Alternate wetting and drying can cut water use by 30% and methane emissions by 30 to 70% without impacting yield.
但是有个好消息。 水稻实际上并不需要在 持续被洪水淹没的稻田里生长。 研究人员和种植者正在 探索水资源管理策略, 这些策略可以在保持 产量的同时减少甲烷。 一种被看好的技术被称为干湿循环。 种植者定期让水位下降, 从而控制甲烷的生长。 干湿循环可以减少 30% 的用水量 和 30% 到 70% 的甲烷 排放但不影响产量。
Greenhouse gases come from many— sometimes unexpected— places. Making rice growing more sustainable is just one of the many challenges we'll need to face to avoid catastrophic warming. Today, many rice growers still flood fields all season long. Changing millennia-old practices requires a major mindset shift. But going against the grain could be just what we need to keep our planet healthy and our bowls full.
温室气体来自许多有时 是意想不到的地方。 提高水稻种植的可持续性 只是我们为避免灾难性变暖 而需要面对的众多挑战之一。 今天,许多水稻种植者 仍在整季淹没田地。 改变千禧一代的做法需要 重大的思维方式转变。 但是,与谷物的周旋可能 正是我们维护地球健康 和吃饱饭所需要的。