[Effects of understory removal and nitrogen addition on the soil chemical and biological properties of Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land].
A full factorial experiment was conducted to study the effects of understory removal and nitrogen addition (8 g x m(-2)) on the soil NO(3-)-N and NH(4+)-N concentrations, potential net nitrogen mineralization rate (PNM) and nitrification rate (PNN), microbial biomass C (MBC) and N (MBN), MBC/MBN, urease and acid phosphomonoesterase activities, and Olsen-P concentration in a Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land during a growth season. Understory removal decreased the soil NH(4+)-N concentration, PNM, MBC, and MBN/MBN significantly, increased the soil Olsen-P concentration, but had little effects on the soil NO(3-)-N concentration, PNN, and urease and acid phosphomonoesterase activities. Nitrogen addition increased the soil NO(3-)-N concentration, PNM and PNN significantly, but had little effects on the other test properties. The interaction between understory removal and nitrogen addition had significant effects on the soil NH(4+)-N concentration, but little effects on the soil NO(3-)-N concentration. However, the soil NO(3-)-N concentration in the plots of understory removal with nitrogen addition was increased by 27%, compared with the plots of nitrogen addition alone, which might lead to the leaching of NO3-. It was suggested that understory vegetation could play an important role in affecting the soil chemical and biological properties in Mongolian pine plantations, and hence, the importance of understory vegetation should not be neglected when the forest management and restoration were implemented.
State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China. linguigang@yahoo.cn
Gui-Gang
GG
Lin
Qiong
Q
Zhao
Lei
L
Zhao
Hui-Chao
HC
Li
De-Hui
DH
Zeng
D019306:Artemisia / Q000187:drug effects / Q000254:growth & development; D002188:Cannabis / Q000187:drug effects / Q000254:growth & development; D002244:Carbon / Q000032:analysis; D002681:China; D003247:Conservation of Natural Resources; D003889:Desert Climate; D017753:Ecosystem; D005308:Fertilizers; D016468:Forestry / Q000379:methods*; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry*; D041605:Pinus sylvestris / Q000254:growth & development*; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
D005308:Fertilizers; D012987:Soil; D002244:Carbon; D009584:Nitrogen