Comparison of Soil Physical and Chemical Properties and Soil Invertebrate Communities between Organic and Conventional Tea Plantations in Taiwan.

Comparison of soil physical and chemical properties and soil invertebrate communities between organic and conventional tea plantations in Taiwan

Kaitlin Ramspeck¹, Chiou-Pin Chen², Chieh-Ting Wang², Ching-Yu Huang¹

¹Department of Biology, University of North Georgia, Dahlonega, Georgia, United States 30597

²Experimental Forest, College of Bio-Resources and Agriculture, National Taiwan University, Taiwan

Tea plantations in Taiwan adopt different farming practices, varying from intensive applications of chemical pesticides and fertilizer (conventional) to no agrochemical application at all (organic). Conventional practice often results in less inhabitable soil environment (e.g. high soil acidity, soil toxicity and heavy soil compaction) for soil invertebrate community that plays a vital role in soil health. Such differences between conventional and organic agricultural practices could potentially affect quality and quantity of tea production.

In this study, we investigated whether organic farming practices can improve soil health, in terms of soil properties and fertility and soil invertebrate community in a previous conventionally managed tea planation in the Fenghuang Tea Plantation of the National Taiwan University Experimental Forest, Nantou County, Taiwan. A total of 30 sampling plots were established in the conventional, transitional and organic tea plantations (ten for each plantation). Soil physical (soil bulk density and moisture content), chemical (soil pH and soil carbon, nitrogen, phosphorous concentrations) and biological data (diversity and composition of soil invertebrate and pest communities) were collected in June 2017 to evaluate the impacts of organic practices to soil environment. The results showed that the transition plantation had the higher soil bulk density (1.00 ± 0.02 g/cm³), as compared to conventional one (0.90 ± 0.02 g/cm³; p = 0.004), and the lowest soil moisture content (42.7 %; p < 0.0001) among all three plantations. Soil pH was not significantly different between different plantations (ranging from 3.2- 3.9). There was a significant difference in soil invertebrate community, particularly oribatid mites and collembolans, between different farming practices (MANOVA; p < 0.0001). Soil nutrients and pest community samples are being processed to explain these changes of the conventional-to-organic transition in tea farming.