太阳能灌溉

If you’re like most Americans, you spend about 12 percent of your annual income each year in grocery stores and restaurants. It may sound like a lot, but now imagine shelling out 50 to 80 percent of your hard-earned cash each year just on food and drink. That’s commonplace in sub-Saharan Africa, where per capita income is much, much lower than just about anywhere else on Earth, and a huge chunk of it is spent on staple nourishment.

普通的美国人每年花费在杂货铺和饭店的钱大约占年收入的12%。这听起来可能很多了，但是如果让你把自己辛辛苦苦挣来的钱的50%～80%都花费在吃喝上面呢？这种情况在撒哈拉以南的非洲非常常见。那里的人均国民生产总值要比世界上任何地方都低得多，而这里面的一大部分都花在了主食上面。

Lessening the food-related financial burden that many Africans bear is a multi-layered problem—spanning global trade, market access, and gender politics, to name a few. But given that most sub-Saharan communities rely on rain-fed agriculture, and given that it only rains between three and six months out of the year in that part of the world, better irrigation is emerging as a simple method for combating poverty and malnutrition.

许多非洲人的食物负担很重，而缓解这一状况也需要考虑多层次的方面——从国际贸易、市场准入一直到性别政治，不一而足。但是鉴于撒哈拉以南的非洲的农业主要依赖降水，并且每年也之后三道六个月的雨季，改良灌溉系统正渐渐成为一个抗击贫困与营养不良的简单方法。

Irrigation schemes come in many flavors, of course. Giant traveling sprinklers lavish water over fields in the US midwest, for instance, while rice plots from southern Louisiana to the Philippines get the full-on treatment of flood irrigation. Drip, or “micro,” irrigation, as the name suggests, is stingier with the water, delivering it to the roots of plants drop by drop. And due to its efficiency, drip irrigation is now the most rapidly expanding model in sub-Saharan Africa—some studies show that it can double yields, deliver water savings of 40 to 80 percent, and reduce the need for fertilizers, pesticides, and manual labor. But a big obstacle to expanding the reach of drip irrigation in Africa has been a lack of reliable energy supplies; even frugal drip schemes need some sort of energy source to power a water pump.

当然，灌溉方案有许多种。比如，巨大的移动喷灌器挥洒了大量的水在美国中西部的大地，而从南路易斯安娜一直到菲律宾，稻田一直都可以受到漫灌的待遇。正如名字所暗示的，滴灌，或者微灌注技术则要抠门的多，它们一滴一滴地把水滴到植物的根部。这种灌溉方式效率高，也成为了撒哈拉以南非洲发展最为迅速的模式。有研究显示，滴灌可以节约40%到80%的水，还可以降低化肥、农药以及人力的耗费。但是，这一地区推广这种技术有一个最大的障碍，就是缺乏稳定可靠的能源供给；即使是采用节俭地主方案也需要一些能源来开动水泵。

Now an innovative research partnership spanning California, Washington D.C., and Niger, is testing a new way to bring water to thirsty plants: photovoltaic drip irrigation (PVDI). Linking the efficiency of drip irrigation to the reliability of a solar-powered water pump, the PVDI systems need no batteries, gas, or kerosene. And in places like rural Benin, where women and girls traditionally haul water by hand, often from very long distances, PVDI can free them from the backbreaking work of tending vegetable crops, especially during the dry season.

现在，一项由加州、华盛顿和尼日尔共同承担的研究正在发展一种新的灌溉模式：光伏滴灌（Photovoltaic drip irrigation, PVDI)。这一系统将滴灌的高效性与太阳能水泵结合起来，它既不需要电池与汽油，也不需要煤油。在贝宁的农村地区，妇女和女孩子们通常都要到很远的地方去拖水。而光伏滴灌系统则可以将她们从这种艰苦的工作中解脱出来，特别是在雨季的时候。

“Our case study on women’s farming groups in rural Benin showed that solar-powered drip irrigation significantly improved nutrition as well as household incomes over the course of a year,” says Jennifer Burney, a post-doctoral student at FSE.

工程师协会的博士后学生Jennifer Burney说，“我们在贝宁农村地区对妇女农业团体进行的案例研究表明，在一年的时间里，太阳能滴灌系统可以显著性地增加该地区人们的营养状况和家庭收入。”

In 2007, Burney and her colleagues partnered with the Solar Electric Light Fund, a D.C.-based NGO, to install irrigation systems in two villages in Benin’s Kalalé district. In both villages, the systems were used and maintained by a group of about 30 women, who collectively grow vegetables for their own families’ consumption and for sale in local markets.

2007年，Burney和她的同事与位于华盛顿地区的非政府组织太阳能电力照明基金会合作，在贝宁的Kalalé地区两个村庄安装了滴灌系统。在这两个村庄里面，这一系统被大约30名女性维护并使用。她们一起工作，生产蔬菜自用或者是在当地的市集进行销售。

The team also set up control plots in both villages, where women hand-watered their vegetable plots, the traditional practice in the region.

这一工作团队和在这两个村庄都设立了对照组农田。那里的女性使用它们传统的方式灌溉她们的农田。

What the researchers found, after just one year of monitoring, was striking: As Burney’s team reported earlier this year in PNAS, the solar-powered drip systems supplied an average of 1.9 metric tons of produce per month—a cornucopia of peppers, tomatoes, okra, eggplants, and carrots—without cutting into the women’s continued cultivation of major staples like corn, sorghum, yam, and cassava. And the women started piling more veggies onto their families’ plates. Usually, during the rainy season, overall vegetable consumption rises by about 150 grams per day. According to household surveys Burney’s team distributed, women tending the test plots were able to feed their families about 500 to 700 grams per day—the equivalent of three to five servings. They also started selling more vegetables on the market, which in turn gave them more money for other types of food, such as meat, milk, and cheese. Several women also earned enough extra cash to begin diversifying. “We saw anecdotally that a lot of women have invested some of the earnings into other small businesses: Some have devoted a portion of their plots to producing seeds to sell to others, some have invested in things like ingredients and bowls to sell prepared food in the market—they’re making a variety of little capital investments.”

经过仅一年的跟踪研究他们就得到了震惊的消息：正如Burney的团队在今年早期PNAS上的文章所报道的，在不影响参加项目的妇女照顾像玉米、甜高粱、甘薯以及木薯等主食的情况下，太阳能灌溉系统每个月平均可以提供1.9吨的食物——大量的辣椒、西红柿、茄子、秋葵以及胡萝卜，餐桌上的蔬菜也多了起来。雨季来临时，一般每天的蔬菜消费量增加了150克。根据Burney团队的家庭问卷调查显示，照顾试验田的妇女可以给家庭提供500到700克的蔬菜，这相当于3到5道菜的数量。她们还在市场上销售更多的蔬菜，利用赚回来的钱去购买诸如肉、奶以及奶酪等食品。有些妇女则用钱做其它的事情了。“非常有意思的是，许多妇女开始投资于其它的事情上了：有些将她们收入的一部分用来生产种子去销售，还有些则用于购买肥料，以及用于销售熟食的桶——她们这种小投资还真是多种多样。”

Solar-powered irrigation systems are but one way that captured sunlight is slowly transforming the developing world. In rural regions, where millions of people have no access to a centralized power grid, photovoltaic micro-grids are beginning to bring electricity to town—and along with that, the chance for computer power, Internet access, and the simple luxury of reading after dusk. Recognizing this enormous potential, the Solar Electric Light Fund has been working since 1990 to raise funds for photovoltaic systems, partnering with companies like Dell and Infosat to donate PCs and satellite uplinks.

太阳能灌溉系统只是改变发展中国家面貌的一种捕捉太阳能的技术。农村地区有上百万人没有通电，而光伏芯片在把电能送到这些地区的同时，也送给他们以电脑、互联网以及天黑后阅读的可能。太阳能光电基金会（Solar Electric Light Fund）在意识到这种巨大的潜能之后，从1990年就开始募集资金来建设光伏系统。他们还与戴尔以及Infosat合作来捐赠电脑以及卫星连接。

The Benin project, however, represents a unique NGO-academic merger. A great deal of non-profit developmental work takes place in a vacuum, without controlled monitoring or scientific evaluation. In partnering with Burney’s group at Stanford, SELF set out to design randomized, single-test treatment projects that could be rigorously studied and analyzed.

然而，贝宁工程则代表了一种独特的NGO-学术界的合作模式。许多非营利性发展项目都是盲目进行，没有科学的监测与评价。在和斯坦福大学的Burney团队合作中，太阳能光电基金会设计了一个随机、单变量的工程，以便于进行细致的研究与分析。

That kind of setup enabled the researchers to put some dollar figures to solar-powered irrigation systems. Each system, they found, costs about $18,000 to install and requires about $5,750 to maintain. Based on farmers’ projected earnings, the systems should pay for themselves in less than two and a half years. Compared with irrigation schemes that rely on gasoline, diesel, or kerosene, PVDI certainly has higher upfront costs, but in the long run, they end up being more economical, says Burney. Not to mention their added benefit of being emissions-free.

这种设计让研究人员可以对太阳能灌溉系统的花费进行估算。他们发现，每个系统的安装费是一万八千美元，而维护的费用则为5750美元。根据农民预计的收入，这一系统可以在两年半以内收回成本。Burney表示，和依赖化石能源的灌溉方案不同的是，这一方法所耗费的前期投入肯定比较高，但是长远看来它们是一种更加经济有效的方法，更别提这些方法不需要排放废气了。

Other results were less quantifiable. “In most cases, these women never earned any income before—so there was an overwhelming sense of pride in the new systems,” says Burney. Now headed back to Benin for phase two of the project, which includes four more villages, Burney hesitates to use the buzz-word “innovative” about her work, but acknowledges a burgeoning interest in linking hard science to development practice at the very early stages. After all, she says, “Everyone wants to know what works.”

其它的结果就不那么容易定量地进行描述了。“在此之前，多数女人从来都没有挣过一分钱——这个项目也给她们带来了前所未有的自豪感，”Burney说。她现在返回到贝宁进行第二期研究了，这次的研究增加了四个村庄。她并没有使用“创新”这一时髦用语来描述她的工作，但是也没有掩饰把科学与实际应用联系起来的兴趣。她说，“毕竟每个人都想知道究竟什么会有用。”