Land use indirectly affects the cycling of multiple nutrients by altering the diazotrophic community in black soil

2021 ◽  
Author(s):  
Jun Yan ◽  
Xiaozeng Han ◽  
Xinchun Lu ◽  
Xu Chen ◽  
Wenxiu Zou
Keyword(s):  
Land Use ◽  
Black Soil ◽  
Diazotrophic Community

scholarly journals A Quantitative Analysis of Factors Influencing Organic Matter Concentration in the Topsoil of Black Soil in Northeast China Based on Spatial Heterogeneous Patterns

2021 ◽  
Vol 10 (5) ◽  
pp. 348
Author(s):  
Zhenbo Du ◽  
Bingbo Gao ◽  
Cong Ou ◽  
Zhenrong Du ◽  
Jianyu Yang ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Erosion ◽  
Soil Type ◽  
Northeast China ◽  
Black Soil ◽  
Factors Affecting ◽  
Soil Zone ◽  
Rainfed Farming ◽  
Study Results

Black soil is fertile, abundant with organic matter (OM) and is exceptional for farming. The black soil zone in northeast China is the third-largest black soil zone globally and produces a quarter of China’s commodity grain. However, the soil organic matter (SOM) in this zone is declining, and the quality of cultivated land is falling off rapidly due to overexploitation and unsustainable management practices. To help develop an integrated protection strategy for black soil, this study aimed to identify the primary factors contributing to SOM degradation. The geographic detector, which can detect both linear and nonlinear relationships and the interactions based on spatial heterogeneous patterns, was used to quantitatively analyze the natural and anthropogenic factors affecting SOM concentration in northeast China. In descending order, the nine factors affecting SOM are temperature, gross domestic product (GDP), elevation, population, soil type, precipitation, soil erosion, land use, and geomorphology. The influence of all factors is significant, and the interaction of any two factors enhances their impact. The SOM concentration decreases with increased temperature, population, soil erosion, elevation and terrain undulation. SOM rises with increased precipitation, initially decreases with increasing GDP but then increases, and varies by soil type and land use. Conclusions about detailed impacts are presented in this paper. For example, wind erosion has a more significant effect than water erosion, and irrigated land has a lower SOM content than dry land. Based on the study results, protection measures, including conservation tillage, farmland shelterbelts, cross-slope ridges, terraces, and rainfed farming are recommended. The conversion of high-quality farmland to non-farm uses should be prohibited.

scholarly journals Elevated Risk of Ecological Land and Underlying Factors Associated with Rapid Urbanization and Overprotected Agriculture in Northeast China

2019 ◽  
Vol 11 (22) ◽  
pp. 6203 ◽  
Author(s):  
Shuhan Liu ◽  
Dongyan Wang ◽  
Guoping Lei ◽  
Hong Li ◽  
Wenbo Li
Keyword(s):  
Land Use ◽  
Urban Expansion ◽  
Black Soil ◽  
Residential Area ◽  
Risk Level ◽  
Ecological Value ◽  
Urbanization Process ◽  
Rapid Urbanization ◽  
Important Indicator ◽  
Farming Area

Ecological land with considerable ecological value can be regarded as an important indicator in guaranteeing ecosystem function and sustainable development. Generally, the urbanization process has been considered to be the primary factor affecting ecological land use. However, the influence of agricultural development, particularly in a typical farming area, has rarely been studied. In this paper, we present a method to assess the ecological risk of ecological land (ELER) in a black soil area in northeastern China. Furthermore, the underlying factors were detected using the geographically weighted regression model, which took into account conditions of natural elements, the urbanization process, and grain production conditions. The results indicate that ecological land experienced remarkable changes with an evident loss and decline from 1996–2015. The ELER progressively increased in the concentrated farming area and the western agro-pastoral ecotone, and the ecological land in the eastern forest area was always at a high risk level. According to the regression coefficients, the relationships between influence factors and ELER could be better explained by the variables of elevation, slope, proportion of rural residential area, and ratio of cultivated land area to residential area. To summarize, agricultural occupation and urban expansion were verified as the two main causes of ecological land loss, as well as elevated risks. In light of the current situation, measures such as policy adjustment and ecological restoration should be taken to avoid risk and optimize land use.

scholarly journals Negative impacts of excessive nitrogen fertilization on the abundance and diversity of diazotrophs in black soil with monocropping maize

2020 ◽  
Author(s):  
La Chen ◽  
Keke Li ◽  
Wenjun Shi ◽  
Xiaolin Wang ◽  
Entao Wang ◽  
...  
Keyword(s):  
Soil Ph ◽  
Nitrogen Fertilizer ◽  
Nitrogen Fertilization ◽  
Black Soil ◽  
Maize Rhizosphere ◽  
N Input ◽  
Use Efficiency ◽  
Abundance And Diversity ◽  
Diazotrophic Community

Abstract Background: Excessive nitrogen fertilizer input and low nitrogen fertilizer use efficiency in maize in China are serious ecological and economic problems, which might affect the procedures in the nitrogen cycle. To reveal the effects of long-term excessive nitrogen fertilization on diazotrophs in maize rhizosphere and bulk soil, we performed a long-term (five-year) N-input experiment (N rates from 0 to 300 kg N ha -1 ) in black soil maize in northeast China. The effect of N fertilizer application rates on the abundance, structure and compositions of diazotrophic community in both the bulk soil and rhizosphere of maize were investigated by Real-time quantitative PCR and high-throughput sequencing, and a structural equation model was constructed based on this study.Results: 1) Excessive N fertilization significantly reduced the abundance and diversity of diazotrophs. 2) The accumulation of Sphingobium was correlated positively with soil nitrate concentration and soil EC, and negatively with soil pH. The contrast correlation was found in Burkholderia . 3) Diazotrophs were enriched in maize rhizosphere, but the diversity and compositions of diazotrophic community were less affected by maize rhizosphere effect. 4) The enriched Bradyrhizobium and Methylobacterium in maize rhizosphere showed a significant positive correlation with of maize plant biomass. Conclusions: Our results suggest that through affecting soil pH, nitrate and EC values, long-term excessive N input increase Sphingobium accumulation and reduce the abundance of beneficial diazotrophs such as Bradyrhizobium and Burkholderia ，which contribute to the decreased nitrogen use efficiency.

Soil physical and hydraulic properties under different land uses in the black soil region of Northeast China

2019 ◽  
Vol 99 (4) ◽  
pp. 406-419 ◽  
Author(s):  
Haiqiang Li ◽  
Xiaolin Liao ◽  
Hansong Zhu ◽  
Xiaorong Wei ◽  
Mingan Shao
Keyword(s):  
Land Use ◽  
Northeast China ◽  
Hydraulic Properties ◽  
Agricultural Land ◽  
Soil Depth ◽  
Black Soil ◽  
Water Retention Curve ◽  
Land Uses ◽  
Undisturbed Soil ◽  
Black Soil Region

Black soil is inherently productive and fertile but is subject to soil erosion. Understanding the distribution of soil physical and hydraulic properties of the soil profile under various land uses would help reveal the mechanism behind the degradation of black soil. In this study, we investigated the variation in soil physical and hydraulic properties with land uses and soil depths in the black soil area of Northeast China. Disturbed samples and undisturbed soil cores were collected from 0–100 cm soil depths under agricultural land (AL), forestland (FL), and shrub land (SL). Our results showed that the land use and soil depth significantly affected the soil bulk density (BD), field capacity (FC), capillary moisture capacity (CMC), saturated hydraulic conductivity (Ks), and soil water retention curve (θs and α). Small macroaggregates accounted for most of the soil mass and were significantly higher in FL but lower in AL for the 0–50 cm of the soil samples. The FC, CMC, and Ks decreased, but the BD increased with the soil depth across the three land-use types. In addition, the soil in AL had a higher BD but lower CMC and Ks than the soil in FL and SL for most soil depths. These results indicated that land use can influence the variation in soil physical and hydraulic properties within the 0–100 cm soil depth, and agricultural use is a major reason for soil degradation in this black soil region.

scholarly journals Abundance and Diversity of Soybean-Nodulating Rhizobia in Black Soil Are Impacted by Land Use and Crop Management

2014 ◽  
Vol 80 (17) ◽  
pp. 5394-5402 ◽  
Author(s):  
Jun Yan ◽  
Xiao Zeng Han ◽  
Zhao Jun Ji ◽  
Yan Li ◽  
En Tao Wang ◽  
...  
Keyword(s):  
Land Use ◽  
Bradyrhizobium Japonicum ◽  
Crop Management ◽  
Black Soil ◽  
Soil Parameters ◽  
Available Phosphorus ◽  
Content Type ◽  
Rhizobial Diversity ◽  
Abundance And Diversity ◽  
Effects Of Land Use

ABSTRACTTo investigate the effects of land use and crop management on soybean rhizobial communities, 280 nodule isolates were trapped from 7 fields with different land use and culture histories. Besides the knownBradyrhizobium japonicum, three novel genospecies were isolated from these fields. Grassland (GL) maintained a higher diversity of soybean bradyrhizobia than the other cultivation systems. Two genospecies (Bradyrhizobiumspp. I and III) were distributed widely in all treatments, whileBradyrhizobiumsp. II was found only in GL treatment. Cultivation with soybeans increased the rhizobial abundance and diversity, except for the soybean monoculture (S-S) treatment. In monoculture systems, soybeans favoredBradyrhizobiumsp. I, while maize and wheat favoredBradyrhizobiumsp. III. Fertilization decreased the rhizobial diversity indexes but did not change the species composition. The organic carbon (OC) and available phosphorus (AP) contents and pH were the main soil parameters positively correlated with the distribution ofBradyrhizobiumspp. I and II andBradyrhizobium japonicumand negatively correlated withBradyrhizobiumsp. III. These results revealed that different land uses and crop management could not only alter the diversity and abundance of soybean rhizobia, but also change interactions between rhizobia and legume or nonlegume plants, which offered novel information about the biogeography of rhizobia.

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