2.3 Harvest and sampling
Destructive sampling (harvest) was conducted twice, one on 1 October 2018 as pre-winter samples, and the other one on 2 April 2019 as post-winter samples. One plant was randomly selected from each sub-sub-plot for each harvest time, and 48 individuals (24 individuals for each species; 3 for each nutrient and drought treatment) were harvested for each time (Fig. S2). The whole plant was harvested, the roots were carefully washed, and the plants were separated into leaves (Oct. 2018 only), shoots, and belowground tissue and separately sampled (leaves, shoots, mixed roots (i.e., fine and coarse roots). The samples were immediately put in an oven at 105°C for half an hour to stop the metabolic activity, and then were dried at 65°C until stable weight. The dried samples were ground to fine powder, using a ball mill (MM 400; Retsch, Haan, Germany), for NSC analysis.