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Accueil du site → Doctorat → Chine → 2010 → Dynamics of the Aboveground Biomass and Soil Physical Properties in the Abandoned Land with Different Treatments in the Semi-arid Loess Plateau of China

Lanzhou University (2010)

Dynamics of the Aboveground Biomass and Soil Physical Properties in the Abandoned Land with Different Treatments in the Semi-arid Loess Plateau of China

郭志彬;

Titre : Dynamics of the Aboveground Biomass and Soil Physical Properties in the Abandoned Land with Different Treatments in the Semi-arid Loess Plateau of China

Auteur : 郭志彬;

Grade : Doctoral Dissertation 2010

Université : Lanzhou University

Résumé partiel
It was important way to improve the ecosystem after conversion of farmland for forest and grassland Regeneration. However, it is hard for us to select which species and how to restore the plant cover after the farmland was abandoned. To improve the ecosystem and develop sustainable agriculture, this experiment was designed. In April 2003, cropland was enclosed and three treatments were implemented :(1) natural regeneration (NR) ; (2) the perennial legume species alfalfa (Medicago sativa Linn.) (AF) ; and (3) the biennial legume species sweetclover (Melilotus officinalis Linn.) (SF).In NR, the aboveground biomass was unstable and significantly differed among years in the experiment. Beside these, the soil water content at depth of 0-500 cm increased significantly. Compared to 2003, the soil pH and soil bulk density in 0-20 cm and 20-40 cm decreased significantly, and the soil water-stable aggregates in >0.25 mm category increased significantly in 2008 ; Moreover, in the large soil aggregates (with diameter in>0.25 mm class) (LSA), middle soil aggregates (with diameter in 0.25-0.05 mm class) (MSA) and small soil aggregates (with diameter in <0.05 mm class)(SSA), the soil organic carbon (SOC) increased significantly, and the total nitrogen (TN) and total soil phosphorus (TP) were no significant differences ; meanwhile, the soil available phosphorus (AP) decreased significantly in all aggregates classes in 2008. During the experiment, the content of SOC, light fraction organic carbon (LFOC) and TN increased, and a positive correlation was existed between SOC, LFOC and TN and the growth years (the values of R was:R=0.659**, R=0.939***, R=0.709**, respectively). During the experiment, the values of SOC to AP (C/AP) and soil microbial biomass carbon (MBC) increased, and the MBC was positively correlated with SOC (R=0.832*) and LFOC(R=0.839*), negatively correlated with AP (R=-0.826*).In SF, the aboveground biomass was stable except 2005 in the experiment. The soil water content in 0-500 cm increased significant in the experiment. During the experiment, the soil pH and bulk density in 0-20 cm and 20-40 cm decreased but the water-stable soil aggregates increased significantly. In all the soil aggregates classes, the SOC and TN increased. In the experiment, the SOC and TN increased and reached the maximum values in 2005 and then declined.

Mots clés : Aboveground Biomass; alfalfa; Sweetclover; Natural regeneration; Soil water; Soil aggregates; Soil organic carbon; Soil microbial carbon; Soil total nitrogen; Soil total phosphorus; Soil available phosphorus; Semiarid Loess Plateau;

Présentation (CNKI)

Page publiée le 23 mai 2018