Regeneration of degraded grassland ecosystems is a significant issue in restoration ecology globally. To understand the effects of artificial management measures on alpine meadows, we surveyed topsoil properties including moisture, organic carbon (SOC), nitrogen (N), and phosphorus (P) contents five years after fencing and fencing + reseeding management practices in a sandy meadow in the eastern Qinghai-Tibetan Plateau, northwestern China. Both the fencing and fencing + reseeding management practices significantly increased soil moisture storage, SOC, total N, available N, total P, and available P, as compared to the unmanaged control. Fencing plus reseeding was more effective than fencing alone for improving soil C, N, and P contents. These suggested that rehabilitation by reseeding and fencing generally had favorable effects on the soil properties in degraded sandy alpine meadows, and was an effective approach for restoration of degraded meadow ecosystems of the Qinghai-Tibetan Plateau. 相似文献
After biochar is applied to soil as a sustainable soil amendment and a carbon (C) sequestration technique, its physicochemical properties change over time. However, few studies have reported on the changes of biochar properties over the aging process under field conditions. An understanding of such changes can help us to make full use of biochar as a sustainable soil amendment and C sequestration technique.
Materials and methods
We used apple tree branches as the raw material to produce biochar and studied the changes in the physicochemical properties of the biochar over a 5-year field experiment. Scanning electron microscopy (SEM), specific surface area (SSA) and micropore area, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy (XPS) were performed.
Results and discussion
After 5 years of aging, the SSA of the biochar had increased by 23.91% relative to that of fresh biochar; however, the SSA initially decreased over the first 3 years and then increased over the next 2 years. The reasons for the initial decrease were the destruction and clogging of the existing pore structure, whereas new micropore formation was responsible for the subsequent increase, as verified by micropore area, SEM and XPS analyses. The C content of the biochar was stable over the 5 years, but the surface O content and quantity of oxygen-containing functional groups increased relative to those of fresh biochar, which impacts the adsorption capacity of the biochar.
Conclusions
Our findings illustrate that the SSA of the biochar varied with time during the aging process. The stability of the C illustrated the potential of biochar as a C sequestration technique. The increase in oxygen-containing functional groups of the biochar was responsible for the process of nutrient adsorption.
It has been suggested that above and belowground interactions produce important feedbacks in natural ecosystems. It is necessary
to study the relationships between aboveground plant functional group traits and belowground biomass and soil chemical properties
in natural grasslands. 相似文献