Study on Water-holding Capacity of Soil Layer and Litter Layer of Chinese Fir Plantations with Different Stand Ages in Northern Guangdong

【Objective】To study the water-holding capacity of soil layer and litter layer of Chinese fir (Cunninghamia lanceolata) plantations with different ages in northern Guangdong, and to provide basis for improving the quality and ecology of Chinese fir Plantations in northern Guangdong.【Method】The young Chinese fir plantations (7-8 years), middle-aged Chinese fir plantations (16-18 years) and near-mature Chinese fir plantations (23-25 years) in three forest farms in Shaoguan City, Guangdong Province were used for study, and the ring knife soaking method and indoor soaking method were applied in the comparative study of the water-holding capacity of soil layer and litter layer. 【Result】In soil layer of 0~30 cm, the soil bulk density of young Chinese fir plantations (1.22 g/cm3) was the highest, followed by middleaged Chinese fir plantations (1.17 g/cm3) and near-mature Chinese fir plantations (1.14 g/cm3); the capillary porosity of young Chinese fir plantations was the largest (39.66%), followed by middle-aged Chinese fir plantations (34.04%) and nearmature Chinese fir plantations (32.93%); the effective water holding capacity of young Chinese fir plantations was the largest (650.70 t/hm2), followed by near-mature Chinese fir plantations (627.60 t/hm2) and middle-aged Chinese fir plantations (524.40 t/hm2), but the difference in the above the aspects was not significant. The effective litter storage capacity of middleaged Chinese fir plantations was the largest (11.01 t/hm2), followed by near-mature Chinese fir plantations (10.95 t/hm2) and young Chinese fir plantations (4.04 t/hm2), and the capacity of middle-aged Chinese fir plantations was significantly higher than that of the two. Regression analysis showed that the litter had the highest water absorption rate within 0.5 h after water soaking, then the rate decreased rapidly, and the water-holding capacity became stable at 12 h after water soaking. The water-holding capacity of litter was logarithmically related to the soaking time (R2 > 0.92), and the water absorption rate was in a power function relationship with the soaking time (R2 > 0.97), and the water absorption rate of near-mature Chinese fir plantations was the highest, followed by middle-aged Chinese fir plantations and young Chinese fir plantations. 【Conclusion】 The soil water-holding capacity of soil layer of Chinese fir plantations with different forest ages is as follows: young Chinese fir plantations had the largest capacity, followed by near-mature Chinese fir plantations and middle-aged Chinese fir plantations; as to the water-holding capacity of litter layer, the near-mature Chinese fir plantations had the largest, followed by middle-aged Chinese fir plantations and young Chinese fir plantations.