Location

The Yuanjiang site's geographical coordinates are 23°28′40″N，102°10′56″E and the elevation is 481m . ;

Climatic

Mean annual air temperature is 23.8℃, with monthly mean values ranging from 16.8 to 28.8℃. The site receives an annual average of 796 mm of precipitation. The region has two distinct seasons influenced by a monsoon climate. The wet season occurs from May through October, and the dry season occurs from November to April

Vegetation and soil

The site is dominated by deciduous woody species, including WD species such as Buchanania latifolia Roxb., Lannea coromandelica (Houtt.) Merr., Symplocos racemosa Roxb. and Phyllanthus emblica L., and DD species such as Polyalthia cerasoides (Roxb.) Benth. et Hook. f. ex Bedd., Terminthia paniculata (Wall. ex G. Don) C. Y. Wu et T. L. Ming, Wendlandia tinctoria subsp. Intermediao (F. C. How) W. C. Chen and Woodfordia fruticosa (L.) Kurz. A few evergreen species were scattered in the vegetation, such as Carissa spinarum L., Cyclobalanopsis helferiana (A. DC.) Oerst., Olea ferruginea Royle, Pistacia weinmannifolia J. Poiss. ex Franch., and Euphorbia antiquorum L., with occasional occurrence of a CAM species. Indigenous grasses, Bothriochloa pertusa (L.) A. Camus and Heteropogon contortus (L.) P. Beauv. ex Roem. Et Schult., and the exotic invasive herbs, Eupatorium coelesticum L. and Eupatorium odoratum L. The soil is a typical US ttorrox with a soil profile of pH 6.1, 1.063% organic matter, 0.104% nitrogen, 0.038% phosphorus and 2.564% potassium at a 0–20 cm depth.

Observation system

The eddy covariance equipment was mounting on a 100 m tower in the center of the permanent plot. Eddy covariance system included a 3‐D sonic anemometer (model R3-50/100, Gill, UK) and an infrared open‐path gas analyzer (model LI‐7500, Li‐Cor Inc., Lincoln, NE, USA). Data was retrieved by a control system (model CR5000, Campbell Scientific Inc., Logan, UT, USA) at a frequency of 10 Hz.

Principal Investigator

Qinghai Song

E-mail: sqh@xtbg.ac.cn