scholarly journals Temporal and spatial variation characteristics of soil mechanical composition after aeolian soil improvement by soft rock in Mu Us sandy land

2021 ◽  
pp. 865-872
Author(s):  
Haiou Zhang ◽  
Tingting Cao ◽  
Xiaomei Sun ◽  
Yan Xu
Keyword(s):  
Mass Fraction ◽  
Fine Particles ◽  
Surface Soil ◽  
Good Condition ◽  
Soil Layer ◽  
Soft Rock ◽  
Clay Content ◽  
Development Trend ◽  
Sandy Land ◽  
Potato Growth

Based on the field experiment of compound soil with volume mixing ratio of soft rock and sand of 1 : 1, 1 : 2, 1 : 5 from 2010 to 2018, the spatio-temporal characteristics and development trend of the mechanical composition of the compound soil with different proportions were studied. The driving factors of the good development of potato growth-compound soil mechanical composition were also explored. Results showed that there was a significant positive correlation between silt-clay mass fraction and cultivation years, the annual variation rates of silt-clay mass fraction were 3.02, 3.90 and 4.11% in 1 : 1, 1 : 2, and 1 : 5 of compound soil. At the initial stage of mixing, clay and silt contents of the compound soil in different proportions were 1 : 1 > 1 : 2 > 1 : 5, and 9 years after planting, clay and silt contents were 1 : 5 > 1 : 2 > 1 : 1, potato growth promoted the development of 1 : 5 compound soil mechanical composition more significantly. The downward migration of silt and clay content in the 0-30 cm surface soil made a relatively dense argic horizon in the 30-40 cm soil layer, which effectively prevented water and fertilizer downward movement and the migration of fine particles in the surface soil. After years of planting, the thickness of the sandy land plow layer has increased to 45 cm, and the three-proportion compound soil mechanical composition developed to a good condition suitable for crop growth, and did not need to be compounded again after many years. Bangladesh J. Bot. 50(3): 865-872, 2021 (September) Special

scholarly journals Response of Fractal Analysis to Soil Quality Succession in Long-Term Compound Soil Improvement of Mu Us Sandy Land, China

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Haiou Zhang ◽  
Jiancang Xie ◽  
Jichang Han ◽  
Haipeng Nan ◽  
Zhen Guo
Keyword(s):  
Organic Matter ◽  
Sandy Soil ◽  
Sustainable Use ◽  
Organic Matter Content ◽  
Soft Rock ◽  
Clay Content ◽  
Matter Content ◽  
Practical Significance ◽  
Sandy Land ◽  
Mu Us Sandy Land

The degraded aeolian sandy soil in China’s Mu Us Sandy Land requires amendment before it can be suitable for maize or other agricultural production. The addition of material from the local “soft” bedrock can create a new compound soil whose particle composition and structural stability are key issues for sustainable soil development in the region. We used field data from 2010 to 2018 to study the variations in fractal characteristics of compound soil particles at soft rock to sand volume ratios of 1 : 1, 1 : 2, and 1 : 5, along with changes in soil organic matter. Over the study period, all three compound soils showed gradual increases in clay and silt content with corresponding decreasing sand content. The fractal dimension (FD) of particles at ratio 1 : 2 increased by 8.8%, higher than those at 1 : 1 (8.6%) and 1 : 5 (7.7%). The organic matter content (OMC) of particles at ratio 1 : 2 reached a maximum (6.24 ± 0.30 g/kg), an increase of 12 times over the original value. The FD and OMC of particles at ratios 1 : 1 and 1 : 5 were less stable but showed overall increase. The 1 : 2 ratio compound soil was most suitable for maize growth as its clear increase in silt and clay content most improved the texture and OMC of the original sandy soil. Such research has important theoretical and practical significance for understanding the evolutionary mechanism and sustainable use of the compound soil in agriculture within the Mu Us Sandy Land.

Outflows of Organic Halide Precursors from Forest Regions

1989 ◽  
Vol 21 (12) ◽  
pp. 1877-1880 ◽  
Author(s):  
S. Saito ◽  
K. Hattori ◽  
T. Okumura
Keyword(s):  
Water Quality ◽  
River Basin ◽  
Surface Soil ◽  
Soil Layer ◽  
Water Quality Monitoring ◽  
Quality Monitoring ◽  
Deep Soil ◽  
Organic Halide ◽  
Forest Regions ◽  
Surface Soil Layer

Outflows of organic halide precursors (OXPs) from forest regions were studied in relation to water quality monitoring in the Yodo River basin. Firstly, the contribution of outflows from forest regions relative to the total was roughly estimated. Then equations for flows of these substances were formulated, divided into four different subflow categories: precipitation; throughfall; surface soil layer; and, deep soil layer. Finally, annual outflow loads were calculated for a test forest area.

scholarly journals Assessment of Seasonal Variability in Soil Nutrients and Its Impact on Soil Quality under Different Land Use Systems of Lower Shiwalik Foothills of Himalaya, India

2021 ◽  
Vol 13 (3) ◽  
pp. 1398
Author(s):  
Tavjot Kaur ◽  
Simerpreet Kaur Sehgal ◽  
Satnam Singh ◽  
Sandeep Sharma ◽  
Salwinder Singh Dhaliwal ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Quality ◽  
Surface Soil ◽  
Sandy Loam ◽  
Monsoon Season ◽  
Soil Layer ◽  
Seasonal Effects ◽  
Land Use Systems ◽  
Post Monsoon ◽  
Significant Difference

The present study was conducted to investigate the seasonal effects of five land use systems (LUSs), i.e., wheat–rice (Triticum aestivum—Oryza sativa) system, sugarcane (Saccharum officinarum), orange (Citrus sinensis) orchard, safeda (Eucalyptus globules) forest, and grassland, on soil quality and nutrient status in the lower Satluj basin of the Shiwalik foothills Himalaya, India. Samples were analyzed for assessment of physico-chemical properties at four soil depths, viz., 0–15, 15–30, 30–45, and 45–60 cm. A total of 120 soil samples were collected in both the seasons. Soil texture was found to be sandy loam and slightly alkaline in nature. The relative trend of soil organic carbon (SOC), macro- and micro-nutrient content for the five LUSs was forest > orchard > grassland > wheat–rice > sugarcane, in the pre- and post-monsoon seasons. SOC was highly correlated with macronutrients and micronutrients, whereas SOC was negatively correlated with soil pH (r = −0.818). The surface soil layer (0–15 cm) had a significantly higher content of SOC, and macro- and micro-nutrients compared to the sub-surface soil layers, due to the presence of more organic content in the soil surface layer. Tukey’s multiple comparison test was applied to assess significant difference (p < 0.05) among the five LUSs at four soil depths in both the seasons. Principle component analysis (PCA) identified that SOC and electrical conductivity (EC) were the most contributing soil indicators among the different land use systems, and that the post-monsoon season had better soil quality compared to the pre-monsoon season. These indicators helped in the assessment of soil health and fertility, and to monitor degraded agroecosystems for future soil conservation.

scholarly journals Biochar induced improvement in root system architecture enhances nutrient assimilation by cotton plant seedlings

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lei Feng ◽  
Wanli Xu ◽  
Guangmu Tang ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Root System ◽  
System Architecture ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Root System Architecture ◽  
Seedling Stage ◽  
Agronomic Efficiency ◽  
Surface Soil Layer

Abstract Background Raising nitrogen use efficiency of crops by improving root system architecture is highly essential not only to reduce costs of agricultural production but also to mitigate climate change. The physiological mechanisms of how biochar affects nitrogen assimilation by crop seedlings have not been well elucidated. Results Here, we report changes in root system architecture, activities of the key enzymes involved in nitrogen assimilation, and cytokinin (CTK) at the seedling stage of cotton with reduced urea usage and biochar application at different soil layers (0–10 cm and 10–20 cm). Active root absorption area, fresh weight, and nitrogen agronomic efficiency increased significantly when urea usage was reduced by 25% and biochar was applied in the surface soil layer. Glutamine oxoglutarate amino transferase (GOGAT) activity was closely related to the application depth of urea/biochar, and it increased when urea/biochar was applied in the 0–10 cm layer. Glutamic-pyruvic transaminase activity (GPT) increased significantly as well. Nitrate reductase (NR) activity was stimulated by CTK in the very fine roots but inhibited in the fine roots. In addition, AMT1;1, gdh3, and gdh2 were significantly up-regulated in the very fine roots when urea usage was reduced by 25% and biochar was applied. Conclusion Nitrogen assimilation efficiency was significantly affected when urea usage was reduced by 25% and biochar was applied in the surface soil layer at the seedling stage of cotton. The co-expression of gdh3 and gdh2 in the fine roots increased nitrogen agronomic efficiency. The synergistic expression of the ammonium transporter gene and gdh3 suggests that biochar may be beneficial to amino acid metabolism.

scholarly journals Winter pasture and cover crops and their effects on soil and summer grain crops

2011 ◽  
Vol 46 (10) ◽  
pp. 1357-1363 ◽  
Author(s):  
Alvadi Antonio Balbinot Junior ◽  
Milton da Veiga ◽  
Anibal de Moraes ◽  
Adelino Pelissari ◽  
Álvaro Luiz Mafra ◽  
...  
Keyword(s):  
Land Use ◽  
Common Bean ◽  
Cover Crops ◽  
Nitrogen Fertilization ◽  
Soil Compaction ◽  
Surface Soil ◽  
Soil Layer ◽  
N Fertilization ◽  
The North ◽  
Oilseed Radish

The objective of this work was to evaluate the effect of winter land use on the amount of residual straw, the physical soil properties and grain yields of maize, common bean and soybean summer crops cultivated in succession. The experiment was carried out in the North Plateau of Santa Catarina state, Brazil, from May 2006 to April 2010. Five strategies of land use in winter were evaluated: intercropping with black oat + ryegrass + vetch, without grazing and nitrogen (N) fertilization (intercropping cover); the same intercropping, with grazing and 100 kg ha-1 of N per year topdressing (pasture with N); the same intercropping, with grazing and without nitrogen fertilization (pasture without N); oilseed radish, without grazing and nitrogen fertilization (oilseed radish); and natural vegetation, without grazing and nitrogen fertilization (fallow). Intercropping cover produces a greater amount of biomass in the system and, consequently, a greater accumulation of total and particulate organic carbon on the surface soil layer. However, land use in winter does not significantly affect soil physical properties related to soil compaction, nor the grain yield of maize, soybean and common bean cultivated in succession.

Surface soil clay content mapping at large scales using multispectral (VNIR–SWIR) ASTER data

2018 ◽  
Vol 40 (4) ◽  
pp. 1506-1533
Author(s):  
Anis Gasmi ◽  
Cécile Gomez ◽  
Philippe Lagacherie ◽  
Hédi Zouari
Keyword(s):  
Surface Soil ◽  
Clay Content ◽  
Aster Data ◽  
Soil Clay ◽  
Soil Clay Content

scholarly journals A Comprehensive Review of the Mechanical Behavior of Suspension Bridge Tunnel-Type Anchorage

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Yafeng Han ◽  
Xinrong Liu ◽  
Ning Wei ◽  
Dongliang Li ◽  
Zhiyun Deng ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Failure Modes ◽  
Load Transfer ◽  
Mechanical Response ◽  
Soft Rock ◽  
Suspension Bridge ◽  
Development Trend ◽  
Factors Affecting ◽  
Research Results ◽  
Rock Strata

The recent surge of interest towards the mechanical response of rock mass produced by tunnel-type anchorage (TTA) has generated a handful of theories and an array of empirical explorations on the topic. However, none of these have attempted to arrange the existing achievements in a systematic way. The present work puts forward an integrative framework laid out over three levels of explanation and practical approach, mechanical behavior, and calculation method of the ultimate pullout force to compare and integrate the existing findings in a meaningful way. First, it reviews the application of TTA in China and analyzes its future development trend. Then, it summarizes the research results of TTA in terms of load transfer characteristics, deformation characteristics, failure modes, and calculation of ultimate uplift resistance. Finally, it introduces four field model tests in soft rock (mainly mudstone formations), and some research results are obtained. Furthermore, it compares the mechanical behavior of TTA in hard rock strata and soft rock strata, highlighting the main factors affecting the stability of TTA in soft rock formation. This paper proposes a series of focused topics for future investigation that would allow deconstruction of the drivers and constraints of the development of TTA.

scholarly journals Development Trend and Stability Analysis of Creep Landslide With Obvious Slip Zone Under Rainfall-Taking Xinchang Xiashan Basalt Slope as an Example

2022 ◽  
Vol 9 ◽  
Author(s):  
Chunyan Bao ◽  
Lingtao Zhan ◽  
Yingjie Xia ◽  
Yongliang Huang ◽  
Zhenxing Zhao
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Stability Analysis ◽  
Soil Layer ◽  
Heavy Rain ◽  
Development Trend ◽  
Sliding Surface ◽  
Landslide Area ◽  
Finite Element Software ◽  
Sliding Zone

The creep slope is a dynamic development process, from stable deformation to instability failure. For the slope with sliding zone, it generally creeps along the sliding zone. If the sliding zone controlling the slope sliding does not have obvious displacement, and the slope has unexpected instability without warning, the harm and potential safety hazard are often much greater than the visible creep. Studying the development trend of this kind of landslide is of great significance to slope treatment and landslide early warning. Taking Xiashan village landslide in Huishan Town, Xinchang County, Zhejiang Province as an example, the landslide point was determined by numerical simulation in 2006. Generally, the landslide is a typical long-term slow deformation towards the free direction. Based on a new round of investigation and monitoring, this paper shows that there are signs of creeping on the surface of the landslide since 2003, and there is no creep on the deep sliding surface. The joint fissures in the landslide area are relatively developed, and rainfall infiltration will soften the soft rock and soil layer and greatly reduce its stability. This paper collects and arranges the rainfall data of the landslide area in recent 30 years, constructs the slope finite element model considering rainfall conditions through ANSYS finite element software, and carries out numerical simulation stability analysis. The results show that if cracks appear below or above the slope’s sliding surface, or are artificially damaged, the sliding surface may develop into weak cracks. Then, the plastic zone of penetration is offset; In the case of heavy rain, the slope can unload itself under the action of rainfall. At this time, the slope was unstable and the landslide happened suddenly.

scholarly journals Biochar effect - mediated ammonium transporter genes and GDH may be the core of improvement nitrogen assimilation in cotton seedling

2020 ◽  
Author(s):  
Lei Feng ◽  
Guangmu Tang ◽  
Wanli Xu ◽  
Meiying Gu ◽  
Zengchao Geng
Keyword(s):  
Seedling Growth ◽  
Fine Roots ◽  
Nitrogen Assimilation ◽  
Surface Soil ◽  
Soil Layer ◽  
Assimilation Efficiency ◽  
Seedling Stage ◽  
Nitrogen Efficiency ◽  
Ammonium Transporter ◽  
Cotton Seedling

AbstractBiochar enhancement of nitrogen efficiency in crops is highly essential not only to reduce costs of agricultural production but also to conserve resources, lower energy consumption for products of these fertilizers, strengthen soil health, and eventually helps in slowing climate change; however nitrogen efficiency physiology by biochar effects is not clear. Here, we reported on the morphological, nitrogen metabolism and cytokinin, at seedling stage, under different layers of biochar and limited urea conditions grown in soil culture. Expression profile of miRNAs and AOB was further studied in fine and medium roots. It showed active root absorption area, fresh weight, and nitrogen agronomic efficiency responded significantly under biochar and reduction by 20% urea condition in the surface soil layer. Also, NR and GPT activity in fine roots remarkably increased with cytokinin, but decreased significantly in medium roots, meanwhile both NR and GDH activity did so. GOGAT activity was to be dependent with biochar and urea locations. In addition, AMT1;1, gdh3 and gdh2 in fine roots showed their up-regulation with reduction 20% urea and biochar. It revealed that co-expression of gdh3 and gdh2 in fine roots significantly affected nitrogen assimilation under reduction 20% urea with biochar on surface soil at seedling stage.HighlightsThe co-expression of ammonium transporter gene and GDH induced by biochar effect improves nitrogen efficiency and seedling growth.These data emphasizes the importance of effects of cytokinin on nitrate reductase activity closely related to the position under biochar condition, which is a key element of enhancement nitrogen assimilation efficiency in cotton seedling.Biochar addition applied into 0 to 10cm soil had a more positive effect on seedling growth than that into 10 to 20cm soil layers.

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