Rice with less water and greenhouse gases is a main topic in this techonology world. An alternate irrigation technology is proving to be a viable option for small farmers growing rice on less than 10 hectares, as it reduces water use by up to 25 percent and limits emissions of gases such as methane and nitrous oxide, which contribute to climate change.
The technique consists of evaluating soil moisture to choose the right moment for a new irrigation on the ground, agronomist Patricia Guzmán, technical manager of the National Federation of Rice Growers of Colombia (Fedearroz) explained to SciDev. Net by telephone.
Sponsored by Fontagro, a technical cooperation entity between the countries of Latin America, the Caribbean and Spain, the technology seeks to reduce the old custom of growing rice in flooded fields without major controls, something unsustainable on a planet where climate variability increases, decreases availability of water and the urgency to reduce greenhouse gas emissions is growing. Rice with less water and greenhouse gases is helpful in such conditions.
The procedure is relatively simple and depends mainly on the installation of plastic pipes 30 cm long and 10-15 cm in diameter to assess the groundwater table and decide when to irrigate. 1 to more than 10 days of non-flooded soil between irrigations can vary. Asian countries already use this low-cost technology.
In the last two years, Fedearroz, the Universidad Nacional Agraria La Molina, of Peru, and the National Institute of Agricultural Research of Chile have conducted trials in three locations Saldaña (Colombia), Ferreñafe (Peru) and Parral (Chile) .
According to the data provided by the program, significant reductions in water consumption were achieved using two modes of humidity (5 and 10 cm). In the first case, an average saving of 14.4 percent was achieved and in the second, 25.4 percent. The crop yield did not show significant variation.
When measuring the greenhouse gases generated by the plots, dissimilar results were found. In Colombia, the program reported a reduction of between 95 and 98 percent in cumulative net methane fluxes and between 46 and 52 percent in cumulative net fluxes of nitrous oxide.
In Chile, a decrease in methane emissions of between 22.6 and 35.0 percent was reported under the two sowing systems. Likewise, the first treatment showed a decrease in nitrous oxide emissions.
In Peru, a decrease in methane emissions and an increase in nitrous oxide emissions were reported in both treatments.
“With this methodology we want to show farmers that with less water, good yields are obtained,” said Guzmán. He also stressed that “if there is no research to adapt and validate technologies created elsewhere they will not work for local farmers.”
A study published in the Proceedings of the National Academy of Sciences in 2019 estimated that up to 14 percent of the land devoted to wheat, corn, rice and soybeans will experience significant reductions in rainfall by 2040, affecting water availability.
Michael Gomez Selvaraj, plant physiologist and researcher at the International Center for Tropical Agriculture in Cali, Colombia, told SciDev. Net via telephone that the use of these technologies in Latin America can be complemented with others, which are being explored by scientists and farmers.
Among them he mentioned drones, to monitor crops efficiently and precisely, or the adoption of varieties of rice with longer roots, such as those that contain the Deeper Rooting 1 (DRO1) gene that allows them to reach the deepest water in soil.
“I find it very interesting that the unions are tackling these problems and are more responsible from an environmental point of view, especially the rice farmers for the amount of water that these crops require,” Saulo Usma, freshwater specialist, told SciDev.Net from WWF Colombia.
According to the Living Planet 2020 report, prepared by this organization at a global level, the cost of agriculture on ecosystems is very high. For example, agriculture is estimated to be responsible for 80 percent of global deforestation, 70 percent of water consumption and loss of terrestrial biodiversity, and 52 percent of land degradation.