Irrigation by surge flooding, a technique used essentially in rice cropping, involves the input of large volumes of water. In some regions, this water does not infiltrate to any depth. Poor infiltration like this can cause severe loss in soil quality and harm crops. Recent investigations on such a situation in a rice field in the River Senegal valley, involving water budget monitoring for 100 days, the length of a cropping season, have confirmed a lack of water infiltration below 40 cm depth. Scientists from the IRD and Pernambuco Federal University of Brazil jointly conducted the project. Mathematical models revealed that air, trapped in dry soil owing to the clay content, is confined and compressed between the wetting front which progresses from the surface and the water table below. The resulting cushion of air creates a blockage, slowing down then stopping the water’s filtration deeper into the soil. This investigation offers new lines of approach that might explain intense salinization of the soil that occurs in some regions of the world.
Rice cultivation uses great volumes of water, especially where the submerged-field method involving surge flooding irrigation is practised. Maintenance of a layer of water on the soil surface throughout the cropping period usually favours its infiltration deeper down. However, it has been known for many years that in some regions water often does not reach deep into the soil. This unusual feature, poorly understood up to now, becomes a problem in rice fields in arid areas because it can have harmful effects. Although from one point of view it conserves a mass of water, in that flow does not penetrate too deeply and remains entirely available for the rice to grow, it can lead to soil quality loss. Absence of infiltration lets mineral salts accumulate in the root zone, and an intense salinization sets in. That process can generate hydraulic stress which acts on the plants, limiting their growth or even killing them.
How can such a low rate of drainage be explained? An IRD team from research unit 67-ARIANE Les sols cultivés à fortes contraintes physico-chimiques des régions chaudes, working jointly with a Brazilian researcher (1), determined the water budget in rice farmers’ plots in the River Senegal valley. They employed mathematical models to define the water-flow events in the soil.
Bénédicte Robert | IRD
Cereals use chemical defenses in a multifunctional manner against different herbivores
06.12.2018 | Max-Planck-Institut für chemische Ökologie
Can rice filter water from ag fields?
05.12.2018 | American Society of Agronomy
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
18.12.2018 | Materials Sciences
18.12.2018 | Physics and Astronomy
18.12.2018 | Physics and Astronomy