Effects of fencing on vegetation and soil restoration in a degraded alkaline grassland in northeast China

Abstract

In order to restore a degraded alkaline grassland, the local government implemented a large restoration project using fences in Changling county, Jilin province, China, in 2000. Grazing was excluded from the protected area, whereas the grazed area was continuously grazed at 8.5 dry sheep equivalent (DSE)/hm 2. In the current research, soil and plant samples were taken from grazed and fenced areas to examine changes in vegetation and soil properties in 2005, 2006 and 2008. Results showed that vegetation characteristics and soil properties improved significantly in the fenced area compared with the grazed area. In the protected area the vegetation cover, height and above-and belowground biomass increased significantly. Soil pH, electrical conductivity and bulk density decreased significantly, but soil organic carbon and total nitrogen concentration increased greatly in the protected area. By comparing the vegetation and soil characteristics with pre-degraded grassland, we found that vegetation can recover 6 years after fencing, and soil pH can be restored 8 years after fencing. However, the restoration of soil organic carbon, total nitrogen and total phosphorus concentrations needed 16, 30 and 19 years, respectively. It is recommended that the stocking rate should be reduced to 1/3 of the current carrying capacity, or that a grazing regime of 1-year of grazing followed by a 2-year rest is adopted to sustain the current status of vegetation and soil resources. However, if N fertilizer is applied, the rest period could be shortened, depending on the rate of application.

Small-Scale Habitat-Specific Variation and Adaptive Divergence of Photosynthetic Pigments in Different Alkali Soils in Reed Identified by Common Garden and Genetic Tests

“…Annual evapotranspiration is 3- to 4-fold the amount of precipitation. Mean daily temperatures greater than 10°C can persist for 120–140 days per year and can reach 21.5–23.6°C (Li et al, 2014). Phragmites australis often grows as a companion species in the alkalized meadow but forms monodominant communities in local low-lying areas or saline-alkaline patches (Yang and Li, 2003).…”

“…Soil moisture was determined by oven drying a known weight of each soil sample at 105°C until a constant weight was reached. Soil pH and EC were determined using a PHS-3C pH meter and a DDS-307 EC meter (Shanghai precision and scientific instrument, Shanghai, China) in a 1:5 soil-water solution (Li et al, 2014). …”

More than a century of Grain for Green Program is expected to restore soil carbon stock on alpine grassland revealed by field 13 C pulse labeling

“…A synthesis of China's GfGP showed that the C stock tended to stabilize after 30 yr of conversion from cropland (Deng et al, 2014). The studies referred to were based on the assumption that soil characteristics would change at a constant rate using either the best fit exponential model of C changes measured during the history (9-15 yr) of restoration (Baer et al, 2015;Craft et al, 2002;Li et al, 2014) or a linear model for up to 30 yr of history (Deng et al, 2014).…”

“…Turnover times of SOC should be greater than the total ecosystem turnover times because the SOC should be stable and recalcitrant, and the restoration time should be longer than the turnover time. Li et al (2014) predicted it might take twice as long to restore degraded grassland as to accomplish the degradation. In the present study, the cultivation commenced in the 1950s, and so spans about 60 yr; the predicted restoration time therefore is about twice the length of the cultivation history.…”

Relationship between urban heat island effect and land use in Taiyuan City, China

“…LOUFAN country and YANGQY country have a sparse population and natural vegetation coverage rate is relatively high, GUJIAO is Taiyuan energy heavy chemical industry base, QINGXU is main crop growth area in TAIYUAN [8] . As seen in the figure, the surrounding temperature is higher in Taiyuan 2000, in 2009, due to the reasons of the image, it is not to be able to show it very well.…”