Fig. 1: Amino-acid contents in soils of a conventional (control) tea plantation and an organic tea plantation.

a Schematic diagram showing the upper region of the soil from which samples were collected in the present study. Soil samples up to 10 cm beneath the surface were collected. b Contents of various amino acids in soils collected from a conventional (control) and an organic tea plantation. c Total amino-acid contents in the soils of the two tea plantations. The data shown are the means ± SDs (n = three replicates)