scholarly journals Spatial Distribution Patterns and Driving Factors of Plant Biomass and Leaf N, P Stoichiometry on the Loess Plateau of China

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2420
Author(s):  
Zhao Fang ◽  
Xiaoyu Han ◽  
Mingyang Xie ◽  
Feng Jiao

Understanding the geographic patterns and potential drivers of leaf stoichiometry and plant biomass is critical for modeling the biogeochemical cycling of ecosystems and to forecast the responses of ecosystems to global changes. Therefore, we studied the spatial patterns and potential drivers of leaf stoichiometry and herb biomass from 15 sites spanning from south to north along a 500 km latitudinal gradient of the Loess Plateau. We found that leaf N and P stoichiometry and the biomass of herb plants varied greatly on the Loess Plateau, showing spatial patterns, and there were significant differences among the four vegetation zones. With increasing latitude (decreasing mean annual temperature and decreasing mean precipitation), aboveground and belowground biomass displayed an opening downward parabolic trend, while the root–shoot ratio gradually decreased. Furthermore, there were significant linear relationships between the leaf nitrogen (N) and phosphorus (P) contents and latitude and climate (mean annual rainfall and mean annual temperature). However, the leaf N/P ratio showed no significant latitudinal or climatic trends. Redundancy analysis and stepwise regression analysis revealed herb biomass and leaf N and P contents were strongly related to environmental driving factors (slope, soil P content and latitude, altitude, mean annual rainfall and mean annual temperature). Compared with global scale results, herb plants on the Loess Plateau are characterized by relatively lower biomass, higher N content, lower P content and a higher N/P ratio, and vegetative growth may be more susceptible to P limitation. These findings indicated that the remarkable spatial distribution patterns of leaf N and P stoichiometry and herb biomass were jointly regulated by the climate, soil properties and topographic properties, providing new insights into potential vegetation restoration strategies.

2018 ◽  
Author(s):  
Xu Manhou ◽  
Zhang Shixiong ◽  
Yang Xiaoyan ◽  
Wen Jing ◽  
Liu Min

Background. Researchers frequently discuss spatial distribution patterns of species diversity and biomass together with their correlations along geographical gradients. Typical subalpine meadows occur widely on the east of the Loess Plateau, China. In recent years, with a rapid development of tourism and pasture husbandry, subalpine meadows have experienced extensive and severe degradation caused by humans in the mountain systems of the Plateau, where their environments are sensitive and fragile, meadows degradation had been increasing, and biodiversity has been threatened seriously. Methods. In our study, we selected nine mountains belonging to four mountain systems from north to south on the east of the plateau. We analyzed five latitudinal and longitudinal gradients together with six elevational gradients to study the spatial distribution patterns of species diversity (including α, β, and γ diversity) and biomass plus with their relationships at various scales. Results. For diversity, α-Diversity manifested unimodal variation patterns in horizontal spaces, peaking at high latitude and low longitude. However, α-diversity was not sensitive to elevation in vertical spaces and tended to decrease with increasing elevation. With increased latitude, longitude, and elevation, β-Diversity diminished; meanwhile, the rate of species turnover decreased and the similarity of community composition enlarged. γ-Diversity demonstrated quadratic function changes that were initially incremental and then decreased with increasing longitude, elevation, and latitude from 37.5° to 40°. For biomass, changes of aboveground biomass (AB) were more obvious along latitudinal gradients, whereas variations of belowground biomass (BB) had smaller differences along longitudinal and latitudinal gradients. More biomass was allocated to BB toward the north and east, whereas total biomass (TB) allocation was more evident at greater latitude than greater longitude. With increased elevation, more TB was also allocated to BB, and the relationship of biomass to elevation was closer in AB. In addition, species diversity had the strongest positive influence on AB. The Patrick and Shannon indices had correlations of power functions with AB and root-to-shoot ratio, respectively, indicating that an allometric model could be used to model relationships between species diversity and biomass. Discussion. The unique geomorphological structures with a series of basins between mountain systems on the east of the Loess Plateau, meant that subalpine meadows were mostly distributed along latitudinal directions, so the spatial distribution of species diversity and biomass was more evident along latitudinal gradients, and thus the response of aboveground biomass was more sensitive to variations of spatial gradients and species diversity.


2019 ◽  
Vol 13 (1) ◽  
pp. 114-121 ◽  
Author(s):  
Ke Zhang ◽  
Mengmeng Li ◽  
Yongzhong Su ◽  
Rong Yang

Abstract Aims Understanding the regional pattern of leaf stoichiometry and its contributing variables are of importance for predicting plant responses to global change and modelling the productivity and nutrient fluxes of ecosystems. In this study, we investigated leaf stoichiometry of plants that sampled from Hexi Corridor, a typical arid region in China, and tried to explore the contribution variables on leaf stoichiometry along the geographic, climatic, and soil gradients. Methods In August 2012, 70 sites in Hexi Corridor were investigated. Plant leaves and soils from five equivalent plots within each site were sampled. C, N, and P contents of leaf and soil were measured. Important findings Compared with leaf N and P contents in regional and global scales, leaf N content in Hexi Corridor was close to them with the value of 20.19 mg g-1, while leaf P content was lower than them with the value of 1.34 mg g-1. Overall, leaf N:P value in Hexi Corridor was 15.70. Individually, leaf N:P values of shrubs and herbs were 16.81 and 14.80, respectively. Scaling exponents for leaf N vs. P of overall and shrubs in Hexi Corridor were 1.29, higher than the scaling exponent of herbs (1.08). Leaf stoichiometry of shrubs and herbs did not show significant latitudinal and longitudinal patterns, meanwhile, it has no significant correlation with mean annual precipitation (MAP), mean annual temperature (MAT), and soil elements. However, only leaf stoichiometry of herbs has significant correlation with altitude and aridity degree. These results indicate that plants in Hexi Corridor are possibly co-limited by N and P, while shrubs are mainly limited by soil P and herbs are limited by soil N. Scaling relationship reveals that leaf N vs. P of herbs is isometric. With increasing altitude, the quadratic regression for leaf C and N contents and the linear regression for leaf P content of herbs reflect the difference responses of the three elements on the variation of MAT along the altitude and it could be explained by plant physiology hypothesis and biogeochemical hypotheses. With decreasing aridity, leaf N and N:P of herbs increased significantly, inferring that herbs growth would be limited by P increasingly and strengthening the increasing nitrogen availability with increasing precipitation. In conclusion, different altitude and aridity patterns for leaf stoichiometry of herbs and shrubs reveal the plastic survive strategies of different xerophytes in Hexi Corridor. Moreover, leaf stoichiometry of herbs in Hexi Corridor could be as indicator of the changing environment that caused by aridity.


2018 ◽  
Author(s):  
Xu Manhou ◽  
Zhang Shixiong ◽  
Yang Xiaoyan ◽  
Wen Jing ◽  
Liu Min

Background. Researchers frequently discuss spatial distribution patterns of species diversity and biomass together with their correlations along geographical gradients. Typical subalpine meadows occur widely on the east of the Loess Plateau, China. In recent years, with a rapid development of tourism and pasture husbandry, subalpine meadows have experienced extensive and severe degradation caused by humans in the mountain systems of the Plateau, where their environments are sensitive and fragile, meadows degradation had been increasing, and biodiversity has been threatened seriously. Methods. In our study, we selected nine mountains belonging to four mountain systems from north to south on the east of the plateau. We analyzed five latitudinal and longitudinal gradients together with six elevational gradients to study the spatial distribution patterns of species diversity (including α, β, and γ diversity) and biomass plus with their relationships at various scales. Results. For diversity, α-Diversity manifested unimodal variation patterns in horizontal spaces, peaking at high latitude and low longitude. However, α-diversity was not sensitive to elevation in vertical spaces and tended to decrease with increasing elevation. With increased latitude, longitude, and elevation, β-Diversity diminished; meanwhile, the rate of species turnover decreased and the similarity of community composition enlarged. γ-Diversity demonstrated quadratic function changes that were initially incremental and then decreased with increasing longitude, elevation, and latitude from 37.5° to 40°. For biomass, changes of aboveground biomass (AB) were more obvious along latitudinal gradients, whereas variations of belowground biomass (BB) had smaller differences along longitudinal and latitudinal gradients. More biomass was allocated to BB toward the north and east, whereas total biomass (TB) allocation was more evident at greater latitude than greater longitude. With increased elevation, more TB was also allocated to BB, and the relationship of biomass to elevation was closer in AB. In addition, species diversity had the strongest positive influence on AB. The Patrick and Shannon indices had correlations of power functions with AB and root-to-shoot ratio, respectively, indicating that an allometric model could be used to model relationships between species diversity and biomass. Discussion. The unique geomorphological structures with a series of basins between mountain systems on the east of the Loess Plateau, meant that subalpine meadows were mostly distributed along latitudinal directions, so the spatial distribution of species diversity and biomass was more evident along latitudinal gradients, and thus the response of aboveground biomass was more sensitive to variations of spatial gradients and species diversity.


Soil Research ◽  
2017 ◽  
Vol 55 (3) ◽  
pp. 285 ◽  
Author(s):  
Xiaolong Ren ◽  
Peng Zhang ◽  
Xiaoli Liu ◽  
Shahzad Ali ◽  
Xiaoli Chen ◽  
...  

Rain-harvesting planting can improve crop biomass and enhance precipitation use efficiency in rainfed semiarid areas. In this study, field trials were conducted during summer 2007–2010 to determine the impacts of different mulching patterns in rainfall harvesting planting on spring corn growth and development in a typical semihumid dryland farming area of the Loess Plateau in China, which is characterised by spring droughts. Rain-harvesting ridges and planting furrows were mulched with 8% biodegradable film (RCSB), liquid film (RCSL), or not mulched (RCSN), and bare land drilling without mulching served as the control (CF). We found that the rain-harvesting effects of ridges and the evaporation-inhibiting and moisture-conserving effects of mulching materials during the spring corn growing season significantly increased water storage in the 0–100cm soil layer (P<0.05) compared with CF, where mulching was more beneficial than the non-mulching treatments. In the 100–200cm soil layers, there were no significant effects (P>0.05) of the treatments on water storage. During 2007–2010, the average plant height increased by 26.6%, 15.4%, and 11.1% under RCSB, RCSL, and RCSN relative to CF respectively, whereas the per plant biomass increased by 26.6%, 15.4%, and 11.1% under these treatments, and the grain yield increased by 32.3%, 17.5%, and 15.0%. Therefore, in the semihumid dryland farming areas of the Loess Plateau, rain-harvesting planting greatly increased the growth, development, and dry matter accumulation by spring corn, thereby enhancing its biomass yield, whereas the plastic-covered ridges and furrows mulched with biodegradable films substantially increased the yield-enhancing effects.


2014 ◽  
Vol 57 (9) ◽  
pp. 2135-2147 ◽  
Author(s):  
Qiang Zhang ◽  
Liang Zhang ◽  
Jing Huang ◽  
LiYang Zhang ◽  
WenYu Wang ◽  
...  

2019 ◽  
Vol 11 (2) ◽  
pp. 228-240 ◽  
Author(s):  
Chunlei Zhao ◽  
Ming’an Shao ◽  
Xiaoxu Jia ◽  
Laiming Huang ◽  
Yuanjun Zhu

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 352 ◽  
Author(s):  
Ning Wang ◽  
Zhihong Yao ◽  
Wanqing Liu ◽  
Xizhi Lv ◽  
Mengdie Ma

Runoff erosion capacity has significant effects on the spatial distribution of soil erosion and soil losses. But few studies have been conducted to evaluate these effects in the Loess Plateau. In this study, an adjusted SWAT model was used to simulate the hydrological process of the Xihe River basin from 1993 to 2012. The spatial variabilities between runoff erosion capacity and underlying surface factors were analyzed by combining spatial gradient analysis and GWR (Geographically Weighted Regression) analysis. The results show that the spatial distribution of runoff erosion capacity in the studying area has the following characteristics: strong in the north, weak in the south, strong in the west, and weak in the east. Topographic factors are the dominant factors of runoff erosion in the upper reaches of the basin. Runoff erosion capacity becomes stronger with the increase of altitude and gradient. In the middle reaches area, the land with low vegetation coverage, as well as arable land, show strong runoff erosion ability. In the downstream areas, the runoff erosion capacity is weak because of better underlying surface conditions. Compared with topographic and vegetation factors, soil factors have less impact on runoff erosion. The red clay and mountain soil in this region have stronger runoff erosion capacities compared with other types of soils, with average runoff modulus of 1.79 × 10−3 m3/s·km2 and 1.68 × 10−3 m3/s·km2, respectively, and runoff erosion power of 0.48 × 10−4 m4/s·km2 and 0.34 × 10−4 m4/s·km2, respectively. The runoff erosion capacity of the alluvial soil is weak, with an average runoff modulus of 0.96 × 10−3 m3/s·km2 and average erosion power of 0.198 × 10−4 m4/s·km2. This study illustrates the spatial distribution characteristics and influencing factors of hydraulic erosion in the Xihe River Basin from the perspective of energy. It contributes to the purposeful utilization of water and soil resources in the Xihe River Basin and provides a theoretical support for controlling the soil erosion in the Hilly-gully region of the Loess Plateau.


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