Stoichiometry of Soil-Microbe-Plant-Litter Ecosystem at Plantations Growing Different Tea Varieties

Objective Stoichiometric characteristics of the soil-microbes-plant-litter ecosystem at tea plantations in Pu'an County, Guizhou that grew different varieties of teas were analyzed to aid the development of a sustainable resource utilization for the local tea industry.

Method Based on field surveys and indoor studies on area plantations of varied teas, i.e., Baiye 1, Huangjinye, Longjing 43, and Wuniuzao, measurements on C, N, and P in the soil, microbes, tea plants, and tree litter were used to analyze the stoichiometry and calculate the nutrient absorption efficiency of the cultivation.

Result Among all samples, the soil at the Wuniuzao tea plantation had the highest organic C and total N, as well as C:P and N:P ratios, and that at the Baiye 1 tea plantation, total P. The microbial C ranged 295.68-443.52 mg·kg⁻¹, N and P were low, and C:P fell between 47.59 and 142.79 in the plantation soils. (2) The plant N:P ratios were 15.25-21.73. The growth of Longjing 43 and Wuniuzao tea bushes were both restricted by the availability of P, while that of Huangjinye by N as well as P. The N:P of the tree litter were 16.12-29.52 with the litter decomposition confined by available N in all soils except that from the Longjing 43 plantation. At the Baiye 1 and the Wuniuzao tea plantations, the re-absorption efficiency on N was greater than on P. Whereas, at the Huangjinye and the Longjing 43 plantations, it was the opposite. (3) The microbial C and N extremely significant or significantly correlated to organic carbon and total nitrogen in soil. However, no significant correlation was observed on stoichiometry between the soil and the plant.

Conclusion In the area where this study was conducted the soil was rich on organic C, total N, total P, and microbial N, but low on P. The growth of tea plants, aside from Baiye 1, was basically limited by the supply of P, on which the plants had also to compete with the microorganisms in the same ecosystem. Hence, supplementation of P fertilizer at the tea plantations was highly desirable.