NEBRASKA – Three soil scientists based at the University of Nebraska Panhandle Research and Extension Center are part of a group of 400 scientists from around the world who have compiled a technical manual, just published by the United Nations Food and Agriculture Organization (FAO), that lists soil management practices aimed at helping capture more carbon in soils globally.

“Recarbonizing global soils: A technical manual of recommended management practices” was launched this month during the FAO’s Ninth Global Soil Partnership Plenary Assembly. The FAO manual consists of six volumes and provides the tools to encourage soil organic carbon (SOC) sequestration.

According to UN, this six-volume manual is the first attempt to collect good soil management practices that are supported by sound scientific data on the impacts of these practices on SOC content in a wide array of environments and land uses. The manual is the result of three years of collective effort by more than 400 scientists. 

The three from the Panhandle – Dr. Bijesh Maharjan, UNL assistant professor in soil science and agronomy and extension specialist, and his coauthors, Dr. Saurav Das (post-doctorate research associate) and Deepak Ghimire (Ph.D. student) – reported on fertigation, the application of fertilizer with irrigation water, and its effect on SOC.

Their chapter provided an overview of fertigation and its potential benefits on crop production and SOC sequestration. According to Maharjan, Das and Ghimire, fertigation combined with improved irrigation scheduling can improve fertilizer uptake efficiency, enhance water-use efficiency, increase the residence time of nutrients in the root zone, and reduce environmental implications.

When integrated with the internet of things (IoT) and sensors, fertigation can be a useful modern agronomic practice for sustainable agriculture. However, Maharjan also shared concerns that rain can delay fertigation, and thus delay fertilization, which can be critical depending on crop-growth stage.

The report highlights some other issues with fertigation, such as potential salt accumulation around emitters and the need of backflow prevention, which need to be addressed in fertigation - an otherwise effective practice in conserving resources and enhancing SOC sequestration.

According to FAO, the degradation of one-third of the world’s soils has already released up to 78 gigatonnes of carbon into the atmosphere. Maharjan added that “Further loss of already depleted soil carbon stocks through poor soil management would impede meaningful contributions agriculture can play in efforts to curbing carbon emissions.”

“Under the onslaughts of frequent extreme weather events, it is likely that more carbon will be lost to the atmosphere than be sequestered into the soil if business-as-usual agricultural practices continue,” Maharjan said. However, he is optimistic that managing soils in a sustainable way and rehabilitating degraded agricultural soils and grasslands can help mitigate the impacts of the climate crisis and improve food security and nutrition. Healthy soils have proven to be not only more productive, but also more resilient to changing climate patterns and extreme events.

All six volumes of “Recarbonizing Global Soils” are available for download as a PDF file at the project website: http://www.fao.org/global-soil-partnership/areas-of-work/soil-organic-carbon-manual/en/.

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