scholarly journals A New Non-Inserted and Portable FDR Instrument for Measuring Surface Soil Water Content

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2712
Author(s):  
Yunfeng Qiao ◽  
Qiuying Zhang ◽  
Fadong Li ◽  
Shanbao Liu ◽  
Qi Li ◽  
...  
Keyword(s):  
Water Content ◽  
Frequency Domain ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Cycle ◽  
Measurement Instrument ◽  
Soil Nutrient ◽  
High Frequency Oscillation ◽  
The Mean ◽  
The Difference

Soil water content (SWC) is a vital parameter for understanding crop growth and the soil nutrient water cycle. Monitoring SWC without inserting sensors into the soil, which can break the soil structure, has previously been a significant challenge for scientists. In this study, we developed a non-inserted portable frequency domain reflection (NIP-FDR) instrument to monitor SWC continuously and automatically. The working technique of this instrument was based on the improved adjustable high-frequency oscillation method originating from the frequency domain reflection principle. Compared to the control SWC measurement instrument, the difference in SWC at 0–10 cm, 10–20 cm, and 20–30 cm depth was within 1%, 3%, and 15%, respectively, and the mean variation of SWC was less than 5% in the indoor measurements. In the field verification experiment conducted in the summer of 2020, the mean error of SWC measurements at a depth of 0–20 cm was 5%, while we failed to compare SWC at a depth of 20–30 cm due to low variability in the SWC measurement at this depth during the summer measurement period. This pioneer NIP-FDR was able to effectively monitor surface SWC, especially at depths of 0–20 cm.

scholarly journals The Effect of Soil Iron on the Estimation of Soil Water Content Using Dielectric Sensors

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 598
Author(s):  
George Kargas ◽  
Paraskevi Londra ◽  
Marianthi Anastasatou ◽  
Nick Moustakas
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Iron Content ◽  
Sandy Loam ◽  
High Iron Content ◽  
Volumetric Soil Water Content ◽  
High Iron ◽  
The Difference ◽  
Dielectric Sensors

Nowadays, the estimation of volumetric soil water content (θ) through apparent dielectric permittivity (εa) is the most widely used method. The purpose of this study is to investigate the effect of the high iron content of two sandy loam soils on estimating their water content using two dielectric sensors. These sensors are the WET sensor operating at 20 MHz and the ML2 sensor operating at 100 MHz. Experiments on specific soil columns, in the laboratory, by mixing different amounts of water in the soils to obtain a range of θ values under constant temperature conditions were conducted. Analysis of the results showed that both sensors, based on manufacturer calibration, led to overestimation of θ. This overestimation is due to the high measured values of εa by both sensors used. The WET sensor, operating at a lower frequency and being strongly affected by soil characteristics, showed the greatest overestimation. The difference of εa values between the two sensors ranged from 14 to 19 units at the maximum actual soil water content (θm). Compared to the Topp equation, the WET sensor measures 2.3 to 2.8 fold higher value of εa. From the results, it was shown that the relationship θm-εa0.5 remained linear even in the case of these soils with high iron content and the multi-point calibration (CALALL) is a good option where individual calibration is needed.

scholarly journals Process-based modelling of NH<sub>3</sub> exchange with grazed grasslands

2017 ◽  
Vol 14 (18) ◽  
pp. 4161-4193 ◽  
Author(s):  
Andrea Móring ◽  
Massimo Vieno ◽  
Ruth M. Doherty ◽  
Celia Milford ◽  
Eiko Nemitz ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Ph ◽  
Regional Scale ◽  
Scale Model ◽  
Nh3 Emission ◽  
Initial Soil ◽  
The Difference

Abstract. In this study the GAG model, a process-based ammonia (NH3) emission model for urine patches, was extended and applied for the field scale. The new model (GAG_field) was tested over two modelling periods, for which micrometeorological NH3 flux data were available. Acknowledging uncertainties in the measurements, the model was able to simulate the main features of the observed fluxes. The temporal evolution of the simulated NH3 exchange flux was found to be dominated by NH3 emission from the urine patches, offset by simultaneous NH3 deposition to areas of the field not affected by urine. The simulations show how NH3 fluxes over a grazed field in a given day can be affected by urine patches deposited several days earlier, linked to the interaction of volatilization processes with soil pH dynamics. Sensitivity analysis showed that GAG_field was more sensitive to soil buffering capacity (β), field capacity (θfc) and permanent wilting point (θpwp) than the patch-scale model. The reason for these different sensitivities is dual. Firstly, the difference originates from the different scales. Secondly, the difference can be explained by the different initial soil pH and physical properties, which determine the maximum volume of urine that can be stored in the NH3 source layer. It was found that in the case of urine patches with a higher initial soil pH and higher initial soil water content, the sensitivity of NH3 exchange to β was stronger. Also, in the case of a higher initial soil water content, NH3 exchange was more sensitive to the changes in θfc and θpwp. The sensitivity analysis showed that the nitrogen content of urine (cN) is associated with high uncertainty in the simulated fluxes. However, model experiments based on cN values randomized from an estimated statistical distribution indicated that this uncertainty is considerably smaller in practice. Finally, GAG_field was tested with a constant soil pH of 7.5. The variation of NH3 fluxes simulated in this way showed a good agreement with those from the simulations with the original approach, accounting for a dynamically changing soil pH. These results suggest a way for model simplification when GAG_field is applied later at regional scale.

Effect of forest and grassland vegetation on soil hydrology in Mátra Mountains (Hungary)

Biologia ◽  
2006 ◽  
Vol 61 (19) ◽  
Author(s):  
Andrea Hagyó ◽  
Kálmán Rajkai ◽  
Zoltán Nagy
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Retention ◽  
Soil Layer ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Mountain Area ◽  
The Difference

AbstractWater retention characteristics, rainfall, throughfall and soil water content dynamics were investigated in a low mountain area to compare a forest and a grassland. The soil water retention curve of the topsoil has similar shape in both studied areas, however that of the deeper soil layer shows more difference. We determined the precipitation depth, duration and intensity values of rainfall events. The relationship between rainfall and throughfall depth was described in linear regressions. Interception was calculated as the difference between rainfall and throughfall plus stemflow, assuming stemflow to be 3% of rainfall. Soil water content dynamics show a similar trend in the two vegetation types but the drying is more intensive in the forest in the soil layers deeper than 20 cm during the growing-season.

scholarly journals PERBEDAAN KEMAMPUAN TANAH DALAM MENAHAN AIR PADA BERBAGAI KELERENGAN LAHAN KOPI DI DAERAH SUMBERMANJING WETAN, KABUPATEN MALANG

2021 ◽  
Vol 8 (2) ◽  
pp. 481-491
Author(s):  
Awal Maulana Faiz ◽  
Sugeng Prijono
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Land Surface ◽  
Ground Surface ◽  
Sloping Ground ◽  
Living Things ◽  
Sloping Land ◽  
The Difference ◽  
Different Levels

Water is a natural resource that is very important because its existence is needed for living things, including plants that need water for their growth and development. The availability of water in the soil has different amounts because it is influenced by various soil properties in the land. Land that has a sloping ground surface, the movement of water that enters the ground does not only move vertically as in land that has a flat surface but also laterally is parallel to the sloping land surface and moves down the slope. The first land has a slope percentage of 6%, the second has a slope of 13%, the third has a slope of 23%, and the fourth has a slope of 37%. The study consisted of 4 treatments for different levels of a land slope, and nine replication points were carried out. The results of this study indicated that the difference in the level of slope in each land had an effect on the water content in the soil at a depth of 40-60 cm; the higher the percentage of the slope of the land reduced the availability of groundwater. Specific gravity, porosity, and soil meso pore had a significant effect on the soil water content with a positive correlation direction, meaning that the higher the density, porosity, and soil meso pores, the more water available in the soil. Macro pores and soil micro pores had a significant effect on soil water content with a negative correlation, meaning that the higher the macro pores and soil micro pores will reduce the available water in the soil.

scholarly journals Water use pattern of Pinus tabulaeformis in the semiarid region of Loess Plateau, China

2016 ◽  
Vol 25 (3) ◽  
pp. e077 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Zening Wu ◽  
Caihong Hu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Use ◽  
Loess Plateau ◽  
Sap Flow ◽  
Pinus Tabulaeformis ◽  
Flow Measurements ◽  
Stand Transpiration ◽  
The Mean

Aim of the study: We analyzed the water-use strategy of P. tabulaeformis and determine the relationships between environmental factors and transpiration rates in the P. tabulaeformis woodlands.Area of study: Loess Plateau region of Northwest China.Material and Methods: Sap flow density of the P. tabulaeformis trees was measured with Granier-type sensors. Stand transpiration was extrapolated from the sap flow measurements of individual trees using the following Granier equation.Main results: The mean sap flow rates of individual P. tabulaeformis trees ranged from 9 L day−1 to 54 L day−1. Photosynthetically active radiation and vapor pressure deficit were the dominant driving factors of transpiration when soil water content was sufficient (soil water content>16%), considering that soil water content is the primary factor of influencing transpiration at the driest month of the year. During the entire growing season, the maximum and minimum daily stand transpiration rates were 2.93 and 0.78 mm day−1, respectively. The mean stand transpiration rate was 1.9 mm day−1, and the total stand transpiration from May to September was 294.1 mm.Research highlights: This study can serve as a basis for detailed analyses of the water physiology and growth of P. tabulaeformis plantation trees for the later application of a climate-driven process model.Keywords: Sap flow; stand transpiration; environmental factor; Pinus tabulaeformis; Loess Plateau.

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