Sun, Jan 25, 2026 page3

• Plants ‘greener’ than fertilizers: research

  • By Esme Yeh / Staff reporter
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  Research by the Ministry of Agriculture’s Taiwan Livestock Research Institute (TLRI) found that interplanting Napier grass with sunn hemp can effectively increase carbon storage of forage fields without causing soil acidification such as in using nitrogen fertilizers.

  Napier grass is a perennial forage crop that has become commonly adopted in Taiwan since it was introduced from the Philippines in 1961.

  TLRI director-general Huang Jeng-fang (黃振芳) said on Wednesday that the institute conducted research on applying carbon-negative farming to Napier grass fields from 2023 to last year.

  

  Napier grasses are pictured in an undated photograph.

  Photo courtesy of the Taiwan Livestock Research Institute

  Carbon-negative farming refers to an eco-friendly agricultural approach that aims to remove atmospheric carbon dioxide rather than releasing it during cultivation.

  Research showed that only using nitrogen fertilizers in cultivating Napier grass still yielded the most production with the highest crude protein content in the forage crop, showing that nitrogen fertilizers remain more capable of stabilizing the crop’s production and quality, Huang said.

  However, interplanting Napier grass with sunn hemp — combined with reduced amounts of nitrogen fertilizers — showed a better ability to prevent soil acidification and increase soil carbon storage, he said, adding that the application of cow dung fertilizers had similar effects.

  Both approaches boosted soil organic carbon content by 3.6 percent to 5.5 percent after three years of experimentation, higher than the 2.4 percent increase from adopting only nitrogen fertilizers, Huang said.

  Interplanting sunn hemp or using cow dung as fertilizers also demonstrated no significant change in soil pH values, he said.

  This shows that the use of organic fertilizers and environmentally friendly farming practices can not only protect soils from acidification, but can also enhance carbon sink benefits of perennial forage fields, he added.

  Meanwhile, the ministry’s Taoyuan District Agricultural Research and Extension Station has conducted carbon footprint assessments of bok choy produced by an organic farm in Taoyuan’s Longtan District (龍潭).

  The assessments were performed in accordance with the carbon footprint product category rules for vegetables and grains promulgated by the Ministry of Environment, the station said on Wednesday.

  The assessment results showed that each 250g package of bok choy produced by the farm has about 0.35kg of carbon dioxide equivalent in carbon emissions, it said, adding that most emissions were generated during production, accounting for 30.4 percent of total emissions.

  Fertilizers and growing media were carbon emission hotspots in the raw material acquisition stage, particularly as fertilizers can release greenhouse gases like nitrous oxide when they interact with microorganisms in soils, the station said.

  The extraction and long-distance transportation of imported materials such as peat soil could also add to agricultural activities’ carbon emissions, it said.

  Such carbon hotspots reflect low-efficiency points of the production process, the station said, which can be identified via carbon footprint assessments and improved through low-cost measures.

  For example, applying a precision fertilization method on soil test results can prevent excessive fertilizer from generating too much nitrogen — which could turn into nitrous oxide — while replacing imported materials with local materials can reduce the transportation carbon footprint, it said.
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