Spatial distribution and seasonal dynamics of fine roots of Castanea mollissima

Abstract

To confirm the spatial distribution and seasonal dynamics of fine roots in the non-timber forest products breeding and cultivation practice base for Castanea mollissima (chestnut) of Beijing Forestry University in Qianxi, Hebei Province, the monthly dynamics and spatial distribution characteristics of fine root length density and dry weight density in a six-year-old chestnut plantation for the 0-20, 20-40, and 40-60 cm soil layers were studied using the soil coring method. Soil cores with a diameter of 8 cm were taken each month during the growing period (from April to October) about 50 and 100 cm away from the chestnut tree stem. Results showed that the fine root length density with a monthly average value of 1 274.9 m·m-3 had two growth peaks. Compared to the previous month, June and October both had significant difference (P < 0.05), which increased 203.0 m·m-3 and 524.6 m·m-3 separately. The fine root dry weight density had a monthly average value of 184.7 g·m-3 and two growing periods from April to June and from September to October. The fine root dry weight density in October was 39.5 g·m-3 higher compared to that in September (P < 0.05). The value of the fine root length density and dry weight density reached a maximum and changed with the seasons most noticeably in the vertical direction of the 20-40 cm soil layer (P < 0.05). Also, the fine root length density and dry weight density in the horizontal direction about 100 cm were greater than those about 50 cm (P < 0.05). This study indicated that spatial distribution and seasonal dynamics of fine roots likely resulted from spatial soil properties and the growth rule of C. mollissima.