The opportunities and challenges of circular agriculture in Taiwan

Pei-Tzu Kao

Sustainability ； Circular agriculture strategies ； Manure management ； Nutrient cycling

臺中區農業改良場特刊

151號（2023 / 10 / 01）

26 - 45

英文

Changes from the consumer side towards a healthier and less-meat diet and from the production side to reduce environmental pressures are urgently needed in response to the continuous growing population and concerns of unsustainable agricultural practices. Circular agriculture (CA) can be a technology measure for keeping the food system within environmental limits. Although the concepts, definition and principles of CA are various and might not be able to directly transfer from the concepts of circular economy (CE), some principles and strategies from CE can be quite useful after adapted. Narrowing, closing and regenerating are the three main strategy aspects, which aims for optimizing the use of resources, reusing agricultural materials and preserving and enhancing natural capital, respectively. However, all the existing indicators of evaluating the effect of the strategies have their own strength and weakness. Therefore, the effect of a CA practice needs to be evaluated using multiple indicators that cover different aspects. National meta-analyses summarizing the existing CA experiments will be needed for evaluating and presenting the geographical, climatical, and agronomical variances to allow policy makers to interpret and make relevant decision easily. Within all the technical strategies to improve CA, the reuse of biomaterials (food wastes, plant residuals, and animal manures), either as biofuel, biofertilizers or the feedstock of biochar, has great potential to both closing the nutrient loop and enhancing soil health. However, as these biomaterials are not standardized, the nutrient balance (both macro and micro-nutrients), toxic element contents in the materials and their following effects on soil properties, crop nutrition and environment highly depend on their sources, the processing methods and the application methods, of which careful and comprehensive evolution is required. In Taiwan, except for cereal crops, most of the vegetables, fruits, eggs and meat are produced locally, which make the implementation of mixed crop-livestock strategy more possible. The re-utilizing livestock manure can be therefore the most promising approach to improve the sustainability and circularity of agriculture in Taiwan. However, evaluating and tracking data of quantifying the reduced application of artificial fertilizers, especially those dominantly imported, driven by the application of organic fertilizers from different sources, and their further impact on soil and crop nutrition is currently lacking. This makes it difficult to strategically evaluate the impact of the sources and types of organic fertilizers and, in turn, difficult to adjust and improve the systems. Relevant investigation and national meta-analyses of the effect of different approaches and the use of different biomaterials will be most required and challenging.