Litter decomposition and nitrogen release in three quercus species at temperate broad‐leaved forest.

Abstract

Decomposition rates and nitrogen release of leaf litter of Quercus serrata, Q. variabilis and Q. mongolica were studied in temperate broad‐leaved forest ecosystem. Freshly senesced leaves were incubated for 300 days and retrieved every 30 days by litter bag method. Main effects for both species and incubating time were highly statistically significant. Mass loss of litters varied significantly among species (P<0.001) and responded differently with the lapse of time (P<0.001). Decomposing litters showed the early slow mass losses during winter and spring but continual rapid mass losses during summer. The decomposition constant(K) was 0.398 for Q. variabils, 0.340 for Q. mongolica and 0.297 for Q. serrata. The half life of litter was 1.7 years, 2.0 years and 2.3 years and the time required for decomposition of 99% of the litter was 7.5 years, 8.8 years and 10.1 years, respectively. The Initial N concentration was significantly different among species and tended to increase gradually in all litter types as litter decomposed. The positive correlationships between mass loss and C:N ratio revealed that C:N ratio was a good predictor of mass loss of litters. Net N mineralization was occurred as C:N ratio decreased. Q. variabilis showed the immediate and consistent net release of N, and Q. mongolica litter did early immobilization and successive mineralization of N in late decomposition period.