Heterotrophic Soil Respiration Affected by Compound Fertilizer Types in Red Pine (Pinus densiflora S. et Z.) Stands of Korea

Abstract

This study was conducted to evaluate the effects of fertilizer application on heterotrophic soil respiration (Rh) in soil respiration (Rs) components in red pine stands. Two types of fertilizer (N 3 P 4 K 1 = 113:150:37 kg·ha −1 ·year −1 ; P 4 K 1 = 150:37 kg·ha −1 ·year −1 ) were applied manually on the forest floor for two years. Rs and Rh rates were monitored from April 2011 to March 2013. Mean Rs and Rh rates were not significantly affected by fertilizer applications. However, Rh in the second year following fertilizer application fell to 27% for N 3 P 4 K 1 and 17% in P 4 K 1 treatments, while there was an increase of 5% in the control treatments compared with the first fertilization year. The exponential relationships between Rs or Rh rates and the corresponding soil temperature were significant (Rh: R 2 = 0.86-0.90; p < 0.05; Rs: R 2 = 0.86-0.91; p < 0.05) in the fertilizer and control treatments. Q 10 values (Rs increase per 10 • C increase in temperature) in Rs rates were lowest for the N 3 P 4 K 1 treatment (3.47), followed by 3.62 for the P 4 K 1 treatment and 3.60 in the control treatments, while Rh rates were similar among the treatments (3.59-3.64). The results demonstrate the importance of separating Rh rates from Rs rates following a compound fertilizer application.

Long Term Influence of Fertility and Rotation on Soil Nitrification Potential and Nitrifier Communities

“…The samples during this preliminary study were collected in June and August, but due to the low number of samples (and lack of in-field replication that reflects modern statistical methods), we could not assess the intra-annual variation in nitrification potential, nitrifier communities, or the edaphic drivers. Biotic factors, such as microbial enzyme potential and community structure, vary significantly spatiotemporally (8,114,115). Particularly, Nmineralization (116) and urease enzyme activity (117) increase with temperature, resulting in late-season pulses in these enzyme activities.…”

No impact of nitrogen fertilization on carbon sequestration in a temperate Pinus densiflora forest

“…Soil C fluxes were characterized by determining the total soil CO 2 efflux and heterotrophic respiration, whereas soil N fluxes were characterized by determining the net mineralization and nitrification rates using an in situ incubation method. Total soil CO 2 efflux was separated into root- and heterotrophic respiration using a trench method 59 . A root exclusion barrier (50 cm diameter, 30 cm depth, PVC) was installed in each plot, 4 weeks before the treatments were initiated.…”