Study on nutrient character of rhizome of Chinese goldthread in Shizhu at different growth stages

Field investigation and chemical analysis methods were adopted to study the content, proportion and uptake of nutrient in the rhizome of Chinese goldthread plant in different growth years and the relationship between nutrient content of plant and soil available nutrient in Shizhu county of Chingqing city in China. Results indicated that there was a significant quadratic regression relationship between the biomass, leaf weight and rhizome weight (yield) of the rhizome of Chinese goldthread and the growth year from one to five years. Contents and uptake of 12 nutrients in leaf were in the order of NKSCaMgPFeMnZnCuBMo. The orders of nutrient content and uptake were different in rhizome. There was a quadratic regression relationship between the nutrient uptake by leaf of the rhizome of Chinese goldthread and growth years and a power regression relationship between the nutrient uptake by rhizome of the rhizome of Chinese goldthread and growth years (y=axb). The nutrient uptake by leaf was much higher than by rhizome (4.29 to 11.4 times). The contents of organic matter, available N, S, Ca and Zn were higher but lower for other eight nutrient elements in experimental soils. There was a cubic regression relationship between the contents of nutrient in leaf (except Mg, Fe, Cu) and rhizome (except Mg, Mo) of the rhizome of Chinese goldthread and soil available nutrient in different growth years.