Abstract:The profile distribution of soil organic carbon (SOC) and total nitrogen (TN) are important indicators for predicting and simulating the effects of human activities on soil fertility and quality. However, most studies have focused on these changes in surface soil or the top 100 cm of short-term cultivated farmlands in arid regions. In the present study, farmlands cultivated for 0, 10, 15, 30, 80 and 100 years in the Cele oasis, at the southern margin of the Tarim Basin, were selected to examine cultivation eff… Show more
“…Compared previous research in 2008 which showed that the average SOCC on the top 20 cm soil was only 2.89 g kg −1 (Si et al, ), our results showed a much higher amount (6.93 g kg −1 ). This number was also higher compared to other arid areas (e.g., <6 g kg −1 in the oasis of south Tarim basin, Xinjiang; Huang et al, ). The SOCC in the downstream Heihe River was lower than that in the middle reaches, likely due to differences in long‐term scarce precipitation and sparse vegetation.…”
The amount of soil organic carbon (SOC) reflects the ability of ecosystem to sequester carbon (C). In the desert riparian zone of Heihe River basin, northwest China, that has been the subject of an ecological water conveyance since 2000, studies on SOC under different land use types remain scarce. Yet analyzing soil organic carbon content (SOCC) and its spatial distribution in the area is a key component when studying C cycle in this desert ecosystem. We therefore investigated the vertical distribution of SOC and its influencing factors using field study, and we found significant differences among different land use types and soil depths. The average SOCC and soil organic carbon density in the 0–100 cm soil layers were 23.31 g kg−1 and 6.08 kg m−2, respectively. SOCC and soil organic carbon density decreased in the following order: grassland (5.73 g kg−1) > forestland (5.03 g kg−1) > shrubland (4.79 g kg−1) > cropland (4.28 g kg−1) > Gobi desert (2.10 g kg−1). We also found that vegetation and soil properties jointly affected SOCC in this riparian arid zone, in addition to human disturbance, as indicated by a low stratification ratio in the grassland (1.575) and cropland (1.366). When natural vegetation was transformed into cropland, SOCC decreased with the removal of plant biomass and the increase of wind erosion. Consequently, conservation agricultural practices that consider preservation of soil organic matter (e.g., no‐tillage and intercropping with deep‐rooted leguminous perennial plants) should be introduced in order to prevent further degradation.
“…Compared previous research in 2008 which showed that the average SOCC on the top 20 cm soil was only 2.89 g kg −1 (Si et al, ), our results showed a much higher amount (6.93 g kg −1 ). This number was also higher compared to other arid areas (e.g., <6 g kg −1 in the oasis of south Tarim basin, Xinjiang; Huang et al, ). The SOCC in the downstream Heihe River was lower than that in the middle reaches, likely due to differences in long‐term scarce precipitation and sparse vegetation.…”
The amount of soil organic carbon (SOC) reflects the ability of ecosystem to sequester carbon (C). In the desert riparian zone of Heihe River basin, northwest China, that has been the subject of an ecological water conveyance since 2000, studies on SOC under different land use types remain scarce. Yet analyzing soil organic carbon content (SOCC) and its spatial distribution in the area is a key component when studying C cycle in this desert ecosystem. We therefore investigated the vertical distribution of SOC and its influencing factors using field study, and we found significant differences among different land use types and soil depths. The average SOCC and soil organic carbon density in the 0–100 cm soil layers were 23.31 g kg−1 and 6.08 kg m−2, respectively. SOCC and soil organic carbon density decreased in the following order: grassland (5.73 g kg−1) > forestland (5.03 g kg−1) > shrubland (4.79 g kg−1) > cropland (4.28 g kg−1) > Gobi desert (2.10 g kg−1). We also found that vegetation and soil properties jointly affected SOCC in this riparian arid zone, in addition to human disturbance, as indicated by a low stratification ratio in the grassland (1.575) and cropland (1.366). When natural vegetation was transformed into cropland, SOCC decreased with the removal of plant biomass and the increase of wind erosion. Consequently, conservation agricultural practices that consider preservation of soil organic matter (e.g., no‐tillage and intercropping with deep‐rooted leguminous perennial plants) should be introduced in order to prevent further degradation.
“…In addition, other scholars have discovered that although nitrogen additions can increase vegetation productivity, litter inputs from aboveground leaves and underground roots have no significant positive feedback effects on nitrogen additions [46,60]. For Xinjiang, the increase in nitrogen may have been beneficial [47,61]. In regards to the WECC, the weighted average results show that the percentages of overloaded, critically overloaded and not overloaded counties and cities were 6%, 0% and 94%, respectively.…”
Section: Comparative Analysismentioning
confidence: 97%
“…N i represents the quantity of atmospheric pollutants. Different pollutants have different impacts on the environment, and the same pollutant has different impacts in different geographical environments [44][45][46][47]. Therefore, the weighted method to define the relative importance of each pollutant is more in line with the local actual situation.…”
Section: Assessment Of the Aecc • Short Board Effectmentioning
Scientifically assessing the environmental carrying capacity (ECC) based on an evaluation of environmental quality standards (EQSs) holds great significance for establishing a long-term monitoring and early warning mechanism for resources and environmental carrying capacity (RECC) and for coordinating the sustainable development of ecological environments and regional economies. However, it remains unclear whether the evaluation of EQSs based on the short board effect is suitable for environmental assessments under different natural environments. In this research, Xinjiang is used as a case study. Based on the evaluation of EQSs, the atmospheric environmental carrying capacity (AECC), water environmental carrying capacity (WECC) and comprehensive environmental carrying capacity (CECC) are assessed using the short board effect and the weighted average. Additionally, the suitability of ECC evaluation in RECC evaluation is discussed. The results show the following: (1) In the atmosphere, the overload of inhalable particles (PM10) and fine particulate matter (PM2.5) is more serious, while in water, the overload of total nitrogen (TN) is more serious. (2) The percentages of the AECC, WECC and CECC in overloaded counties and cities based on the short board effect are 84%, 45%, and 51%, respectively, while the percentages based on the weighted average are 32%, 6% and 7%, respectively. (3) The extreme effects of a single pollutant can be eliminated by the weighted average, which is more suitable for environmental assessments in Xinjiang. (4) In evaluating RECC monitoring and early warning systems, weighted average evaluation is used to assess the elements, and short board effect evaluation is used in the comprehensive integration to prevent the influence of the amplification of a single index. Thus, the interference of non-key factors in the regional system on the final evaluation results is reduced.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.