Professor Jonathan Wong (centre) and representatives from Kwong Wah Hospital, Dr Eric Chan (left) and Professor Li Handong, share their experience and release the latest research outcome


黃煥忠教授(中)與廣華醫院代表陳巨星博士(左)和李捍東教授分享經驗並發佈最新研究結果

Three pots of Romaine lettuce which had been treated with (from left) normal food waste compost, Chinese medicinal herbal residue compost and soil with fertilizer. The one treated with Chinese medicinal herbal residue is much stronger than the other two.


三棵接受不同肥料的羅馬生菜:(左起)普通廚餘堆肥、中藥藥渣廚餘堆肥及化學肥料。使用中藥藥渣廚餘堆肥的生長明顯較佳

Date: 15 Dec 2014 (Monday)

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HKBU and TWGHs jointly develop food waste compost with biopesticide properties by adding Chinese medicine herbal residue as bulking agent

浸大與東華三院合作首創生物農藥堆肥 以中藥藥渣混合廚餘大幅提升堆肥成效

The HKBU’s Sino-Forest Applied Research Centre for Pearl River Delta Environment (ARCPE) and the Tung Wah Group of Hospitals (TWGHs) have been collaborating since 2013 to improve the efficacy of community food waste composter performance through the use of Chinese medicinal herbal residue as bulking agent in the food waste composting process. The compost produced is effective in pest control due to the presence of natural bioactive compounds. The latest results showed that the compost enhanced plant growth by reducing fungal pathogens by more than 99% when it was applied to plants inoculated with pathogenic fungal populations. This is the first report in the world of a “biopesticide compost derived from Chinese medicinal herbal residue” being produced and is expected to have tremendous market potential.
 
According to the study, the optimised composting mix of 1:1:0.5 ratio (on dry weight basis) of Chinese medicinal herbal residue: food waste: saw dust effectively reduced the composting time from 8-9 weeks to 5 weeks. Moreover, the temperature of the composter could be maintained between 60 to 70°C throughout the composting period, meeting the new EU requirement on compost temperature which was proposed to ensure sufficient heat to kill the pathogens. At such high temperatures, the problem of fat, oil and grease could also be effectively alleviated. The quality of the final product also meets the requirement for “Organic Farming” set by the HKBU’s Hong Kong Organic Resource Centre.
 
In addition, the results showed that Chinese medicinal herbal residue helped boost the bulking condition of compost and its antipathogenic effects. Growth experiments using tomato and Chinese cabbage plants that received Chinese medicinal herbal residue derived compost demonstrated antipathogenic effects and inhibition of two fungal pathogens. About 22 bioactive compounds were found in the compost that contained herbal residues, and seven of these compounds belonging to the groups alkaloids, flavonoids and coumarins were present in significant quantities. These compounds killed bacteria and fungal pathogens. When the compost was applied to tomato and Chinese cabbage plants inoculated with Alternaria solani and Fusarium oxysporum, the pathogenic fungal population was reduced by more than 99% resulting in enhanced plant growth and protection against diseases. A 5% compost application enhanced the biomass by 3.16 and 1.28-fold for tomato plants, and 2.42 and 2.21-fold for Chinese cabbage plants when compared with the control and regular food waste compost, respectively, demonstrating the ability of this product in suppressing fungal pathogens.
 
Professor Jonathan Wong, Director of ARCPE and the project-in-charge of this study, said that this is the first report in the world of producing compost with biopesticide properties by incorporating Chinese medicinal herbal residue into food waste compost. He said that the new compost could be a potential “organic fertiliser” for organic farming where the use of synthetic fertilisers is prohibited. The recycling of organic resources including food waste and Chinese herbal residue through composting is contributive to the exigent food waste problem in Hong Kong. He believed that the application potential of the biopesticide compost is important in crop production as it reduces the reliance on artificial pesticides and fertilisers, and the compost produced has strong market potential locally and internationally.

浸大嘉漢林業珠三角環境應用研究中心與東華三院自2013年開始合作,在廣華醫院研發利用中藥藥渣作為堆肥澎鬆物料,以改善廚餘堆肥效益,並探討利用藥渣的天然生化成份對抗植物病害。最新研究結果顯示,加入中藥藥渣可大幅減低堆肥腐熟週期,而且可殺死超過99%的病原體,令植物生長更旺盛。這是世界首次成功利用中藥藥渣在廚餘堆肥機裡研發出具有生物農藥特性的堆肥,不但能改良廚餘堆肥的效果,亦具有市場潛力。
 
研究結果顯示,中藥藥渣、廚餘和木糠以1:1:0.5的淨重比例能達到最理想堆肥效果,且有效地將堆肥的完全腐熟週期由8-9週大幅度減至5週。在新技術下,可每日投放廚餘,堆肥進行時,機內溫度能夠維持在攝氏70度以上,達到歐盟標準,不只有效殺滅病原體,更完全分解油脂,最終的腐熟堆肥亦達到浸大香港有機資源中心訂定的有機耕作要求。
 
此外,研究結果證實在新技術下產生的堆肥具抗菌能力。團隊以混合中藥藥渣的廚餘堆肥提取物種植番茄和白菜,證實堆肥對兩種潛在的真菌病原體具抑制作用。提取物內共22種具有生物活性的天然化合物來自中藥藥渣,當中7種屬於生物堿、類黃酮或香豆素類的化合物含量豐富。這些物質有效對抗病原體的真菌和細菌的生長,能進一步殺滅病原體。將中藥堆肥加入受馬鈴薯早疫病菌及尖孢鐮刀菌的感染番茄和白菜後,可殺死超過99%的病原體,令植物生長更旺盛。實驗顯示,在種植所用的泥土中加入5%的中藥藥渣廚餘堆肥能夠增加植株的生物量,對比空白對照組別和加入普通廚餘堆肥組別,番茄的生物量分別增加3.16倍及1.28倍,大白菜則增加2.24倍及2.21倍,展示出中藥藥渣廚餘堆肥抑制真菌生長的生物農藥性能。
 
研究項目的負責人、浸大嘉漢林業珠三角環境應用研究中心主任黃煥忠教授表示,這是世界首次成功利用中藥藥渣在廚餘堆肥機裡研發出具有生物農藥特性的堆肥。他說,有機耕作中不能使用化學合成的肥料和殺蟲劑,而這種堆肥所展示的特性讓它成為有機耕作肥料「新寵」的潛力。由於生物農藥堆肥更適合於社區園圃應用,加上改善堆肥配方,將有助推動社區廚餘分類和堆肥。他相信這種創新性的「生物農藥堆肥」能有效應用在農作物生產,減少人工合成化肥和農藥的使用,在本地及世界市場銷售上有巨大潛力。