A UAE farmer was the toast of the Liwa Dates Festival for his hydroponic rice. In proving such a staple could be grown locally, can it be mass-produced without heavy water use?
The UAE has a tradition of overcoming the challenges of its harsh environment to turn the desert green.
So much so that a decade ago the United Nations Environment Programme named the country’s Founding Father, Sheikh Zayed, as one of its Champions of the Earth for overseeing the planting of more than 100 million trees.
Yet even in a nation that has achieved so much in agriculture and horticulture, a display at the recent Liwa Dates Festival managed to raise eyebrows.
Saleh Al Mansouri, an Emirati farmer, showed off rice that he had grown at his Liwa farm. It was impressive achievement given that this staple crop is more associated with waterlogged paddy fields in South-east Asia or the Indian subcontinent than with the UAE’s deserts.
Mr Al Mansouri’s rice was produced using a technique called hydroponics, in which plants are grown without soil. In place of soil, a nutrient solution, and because this fluid can be recycled, water use is strictly controlled. Yields for a given area of land are higher than those where traditional methods were used.
The enterprising Mr Al Mansouri says that hydroponic methods are less complex and expensive than people may imagine, according to reports crediting the Wam news agency. Over the past five years he has used the technique to produce oranges, grapes, pineapples and papayas.
In fact, hydroponics is well established in the UAE, being employed to produce lettuces and other succulent plants.
When it comes to rice, however, Prof Adam Price, a specialist in the crop at the institute of biological and environmental sciences at the University of Aberdeen in Scotland, is “absolutely not aware” of any large-scale hydroponic production anywhere in the world. He adds that there are no biological reasons why rice cannot be grown using hydroponics, and that growing the grain using the method has “potential benefits”.
“It could absolutely save water if you could recover the water, which is potentially of immense value in the parts of the world where water is being used unsustainably to grow rice,” he says.
The growing of rice uses a lot of water, he says, for reasons that are not related to the physiology of the plant, which in its Asian form has the Latin name Oryza sativa. The heavy water consumption is a consequence of the methods used to grow the crop.
“If you grow it in a flooded field, a lot of the water drops out of the bottom, or seeps over the edge. It makes it a very water-thirsty crop,” he says.
Anything that could cut water use in rice cultivation would be of great significance to global agriculture, given that, along with wheat, maize and soybeans, rice accounts for nearly two-thirds of calories produced by agriculture. Also, global production is growing by about one per cent annually, and could increase faster, with some analysts suggesting that total output must double by 2050 to cope with population growth.
Given rice’s position as one of the world’s most significant staple crops, it is perhaps no surprise that a 2012 study in the journal Nature described its domestication thousands of years ago as “one of the most important developments in history”. That research also found that its domestication, from the wild species O rufipogon, took place in the middle of the Pearl River area of China.
A study from a year earlier, released in the Proceedings of the National Academy of Sciences, found that this domestication event took place between about 8,200 and 13,500 years ago. These estimates were derived from studying the genetic differences between various wild and domesticated forms of rice, and using a “molecular clock” based on the idea that mutations accumulate at a steady rate over time.
So, with rice being of huge importance to humankind, and with it being a particularly water-thirsty crop, it begs the question as to why it is not grown hydroponically on a large scale, either in the UAE and elsewhere.
It turns out that the reason has more to do with economics than with biology.
“All crops can be grown hydroponically, but since it is expensive to grow hydroponically, it is typically only used to grow the most high-value crops – like fresh leaf lettuce, basil and spinach,” says Prof Bruce Bugbee, director of the crop physiology laboratory at Utah State University.
“It is far less expensive to grow rice in the field, so it is not grown in hydroponics, except for research purposes.”
To be suitable for growing hydroponically on a commercial basis, a number of factors, in addition to the crop being high value, are crucial, according to Dr Howard Resh, a Canadian hydroponics consultant who has written books on the subject.
Of particular value, he says, are vine crops such as tomatoes, cucumbers, eggplants and peppers. These can be trained vertically in a greenhouse, increasing revenues for a given area of land.
High-value leafy crops such as lettuce, arugula or salad rocket, basil and herbs are also suitable.
“As market value increases the value of crops, such as kale and other herbs, they may be grown hydroponically in vertical growing systems.”
In most cases, special varieties that produce good yields in the controlled environmental conditions of a greenhouse are grown.
It is important, adds Dr Resh, for these hydroponically grown crops to be packaged well so that they can be sold for more than crops grown using standard methods in fields.
While many of these high-value crops will continue to be produced hydroponically in the UAE, it may seem that, for various reasons, rice is unlikely to join their ranks, at least in terms of large-scale production.
Given the UAE’s talent for achieving the impossible, however, when it comes to agriculture and horticulture, the possibility should perhaps not be ruled out, especially as Mr Al Mansouri’s achievements demonstrate the Emirates’ continuing determination to push the agricultural boundaries.