Surface volume soil water content in grasslands versus bamboo stands in a Nanjing suburb

Abstract

In order to evaluate the water conservation function under forest soil, a Phyllostachys edulis bamboo stand and a Leptochloa chinensis grassland in the Tongshan Forestry Farm of Nanjing were selected with four sets (2 replications) of Decagon Em50 Data Loggers used to measure daily average soil Volumetric Water Content (VWC) at depths of 5, 15, and 30 cm with air humidity measured at a 2.0 m height for a year. All data were recorded continuously every 15 minutes. Results in the bamboo stand and grass land showed that (1) daily average soil VWC at 5 cm was 33.02%, at 15 cm was 26.16%, and at 30 cm was 30.60% with the lowest (at 15 cm) having the greatest root weight, root length, and soil compaction. In the grassland daily average soil VWC at corresponding depths was lower than the bamboo stand. For the 0-40 cm soil layer, the average annual VWC in the bamboo stand with thick litter on the ground was 9.12% higher than the grassland, improving by 43.41%. (2) For each land use type the average annual CV for daily average soil VWC was negatively and significantly correlated (R2>0.9, P 0.9, P < 0.001) with rain day interval for different soil layers, which could be used to help predict drought and to assist in drought control management.