Simultaneous use of newly adopted simple sensors for continuous measurements of soil moisture and salinity

Soil Research ◽  
2003 ◽  
Vol 41 (2) ◽  
pp. 309 ◽  
Author(s):  
F. Konukcu ◽  
A. Istanbulluoglu ◽  
I. Kocaman
Keyword(s):  
Thermal Conductivity ◽  
Moisture Content ◽  
Water Content ◽  
Water Table ◽  
Arid Regions ◽  
Sandy Loam ◽  
Clay Loam ◽  
Evaporation Chamber ◽  
Wide Range ◽  
Semi Arid

Methods available to measure salinity and moisture content in arid and semi-arid regions are limited because of the high salinities and very wide range of water contents (i.e. from saturation near the water table to air dry in the evaporation front). This paper is focused on the instrumentation employed in monitoring salt and moisture profiles in a column study which has wide applicability in salinity research. Experiments were conducted in a specially designed evaporation chamber which provided high evaporative demand as experienced in arid and semi-arid regions. Intensively instrumented soil columns with a constant shallow saline water table were used. Moisture content was measured by thermal conductivity and salinity by 4-electrode probe. In each case, instruments were manufactured specifically for the purpose in order to provide the desired degree of spatial resolution. Two soil types, sandy loam and clay loam, were used. Results indicated that thermal-conductivity probes measured water content over a wide range from saturation to 0.16 m3/m3 for clay loam and to 0.09 m3/m3 for sandy loam soil with great sensitivity (R2 > 0.95) and were unaffected by salt accumulation. The 4-electrode probes provided reliable measurements (R2 > 0.95) of the salinity of the soil solution for the range relevant to agricultural application. However, the accuracy of the probe decreased with the decreases in the water content after permanent wilting point.

scholarly journals Simple sensors to achieve fine spatial resolution in continuous measurements of soil moisture and salinity

2002 ◽  
Vol 6 (6) ◽  
pp. 1043-1051 ◽  
Author(s):  
F. Konukcu ◽  
J. W. Gowing ◽  
D. A. Rose
Keyword(s):  
Thermal Conductivity ◽  
Soil Moisture ◽  
Water Content ◽  
Spatial Resolution ◽  
Sandy Loam ◽  
Great Sensitivity ◽  
Fine Spatial Resolution ◽  
Wide Range ◽  
Individual Calibration ◽  
Design Construction

Abstract. It is increasingly necessary to be able to measure, simultaneously, continuously and at fine spatial resolution, the salinity and water content of soil. This paper reports the design, construction, calibration and laboratory testing of two simple but robust instruments that enable this to be achieved. Salinity in solution was measured reliably, at 10-mm spacing, by multi-electrode resistivity probes up to saturation with NaCl (c. 6 mol l–1), though these probes required individual calibration and were unable to detect precipitated salt. Volumetric water content was measured with great sensitivity over a wide range, from air-dryness (0.06 m3m–3) to saturation (0.55 m3m–3) in a sandy loam, using thermal-conductivity probes that used a common calibration and were unaffected by the salinity of the soil solution, by temperature and by ageing. Keywords: soil moisture, soil salinity, thermal-conductivity moisture probe, four-electrode salinity probe

scholarly journals Relating surface backscatter response from TRMM Precipitation Radar to soil moisture: results over a semi-arid region

2009 ◽  
Vol 6 (5) ◽  
pp. 6425-6454
Author(s):  
H. Stephen ◽  
S. Ahmad ◽  
T. C. Piechota ◽  
C. Tang
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Arid Regions ◽  
Vegetation Index ◽  
Temporal Trends ◽  
Model Parameters ◽  
Precipitation Radar ◽  
Semi Arid

Abstract. The Tropical Rainfall Measuring Mission (TRMM) carries aboard the Precipitation Radar (TRMMPR) that measures the backscatter (σ°) of the surface. σ° is sensitive to surface soil moisture and vegetation conditions. Due to sparse vegetation in arid and semi-arid regions, TRMMPR σ° primarily depends on the soil water content. In this study we relate TRMMPR σ° measurements to soil water content (ms) in Lower Colorado River Basin (LCRB). σ° dependence on ms is studied for different vegetation greenness values determined through Normalized Difference Vegetation Index (NDVI). A new model of σ° that couples incidence angle, ms, and NDVI is used to derive parameters and retrieve soil water content. The calibration and validation of this model are performed using simulated and measured ms data. Simulated ms is estimated using Variable Infiltration Capacity (VIC) model whereas measured ms is acquired from ground measuring stations in Walnut Gulch Experimental Watershed (WGEW). σ° model is calibrated using VIC and WGEW ms data during 1998 and the calibrated model is used to derive ms during later years. The temporal trends of derived ms are consistent with VIC and WGEW ms data with correlation coefficient (R) of 0.89 and 0.74, respectively. Derived ms is also consistent with the measured precipitation data with R=0.76. The gridded VIC data is used to calibrate the model at each grid point in LCRB and spatial maps of the model parameters are prepared. The model parameters are spatially coherent with the general regional topography in LCRB. TRMMPR σ° derived soil moisture maps during May (dry) and August (wet) 1999 are spatially similar to VIC estimates with correlation 0.67 and 0.76, respectively. This research provides new insights into Ku-band σ° dependence on soil water content in the arid regions.

Movement of salts in isolated soil columns.

1953 ◽  
Vol 4 (1) ◽  
pp. 82 ◽  
Author(s):  
ES West ◽  
A Howard
Keyword(s):  
Water Table ◽  
Salt Concentration ◽  
Sandy Loam ◽  
Field Conditions ◽  
Lateral Movement ◽  
Soil Columns ◽  
Surface Layers ◽  
Salt Accumulation ◽  
Arid Soil ◽  
Semi Arid

Movement of salt in a semi-arid soil (Hanwood sandy loam) was studied in isolated columns of soil one metre in diameter and four metres deep. Where a water-table was maintained approximately 60 cm. from the surface by the addition of rain-water to the surface, salt was washed out of the surface layers and did not return. Where a water-table was maintained one metre from the surface by the addition of water from below there was a small increase in the salt concentration of the surface 10 cm. of soil. In view of these results it is suggested that some circulation of water involving lateral movement is generally associated with salt accumulation that is commonly found under field conditions.

Root Growth and Yield Response of Rainfed Lowland Rice to Planting Method

1987 ◽  
Vol 23 (3) ◽  
pp. 305-313 ◽  
Author(s):  
P. K. Sharma ◽  
S. K. De Datta ◽  
C. A. Redulla
Keyword(s):  
Root Growth ◽  
Grain Yield ◽  
Water Table ◽  
Sandy Loam ◽  
Lowland Rice ◽  
Yield Response ◽  
Clay Loam ◽  
Transplanted Rice ◽  
Rainfed Lowland ◽  
Loam Soil

SUMMARYField experiments were conducted on two soils (clay loam and sandy loam) with varying texture and water table depth to study the effects of two planting methods (dry seeding and transplanting) on the root growth and grain yield of rainfed lowland rice. About 75% of the roots were found in the top 10 cm soil. Root length density at the flowering stage and grain yield in the sandy loam soil, with a water table deeper than 1.5 m, were less in dry-seeded than in transplanted rice, probably because of the greater moisture stress in dry-seeded rice between late tillering and harvest. In the clay loam soil, with the water table mostly at the soil surface, there was no difference in grain yield between dry-seeded and transplanted rice.

Temperature and moisture content influences aggregate stability: linking climate induced microbial change to aggregate (de)stabilisation

2020 ◽  
Author(s):  
Emily Dowdeswell-Downey ◽  
Robert Grabowski ◽  
Jane Rickson
Keyword(s):  
Climate Change ◽  
Microbial Community ◽  
Moisture Content ◽  
Sandy Loam ◽  
Aggregate Stability ◽  
Climatic Conditions ◽  
Soil Erodibility ◽  
Clay Loam ◽  
Static Conditions ◽  
Microbial Change

<p>Soil is a critical resource that delivers numerous ecosystem services, yet this capacity is diminished by soil erosion and further threatened by the impacts of climate change. Soil erodibility is largely overlooked when considering soils’ response to climate change. Aggregate stability is widely recognised as a key indicator of soil erodibility and is influenced by multiple physical, chemical and biological mechanisms operating simultaneously. The microbial community has been reported to respond to changing climatic conditions, yet it remains unclear how microbial change influences microbially mediated aggregation and therefore aggregate stability. The microbial community in terms of composition, activity, and growth, can change over rapid timescales in response to climate conditions. The short timescale of such microbial shifts could rapidly impact microbially-mediated soil (de)stabilisation and aggregate stability.</p><p>The aim of this work is to experimentally test whether climatic conditions, in terms of temperature and moisture content, influence the microbial community and microbially-mediated soil (de)stabilisation, in turn influencing aggregate stability and soil erodibility. A series of laboratory-controlled experiments using environmental chambers and rainfall simulation examined the effects of temperature and moisture content in both static and fluctuating treatments on two surface soils (a sandy loam and a clay loam). Treatments were conducted with single layer aggregate microcosms and multi-layered soil trays to explore aggregate-scale mechanisms and the potential upscaling to run-off processes.        </p><p>Key findings from this research demonstrate that temperature and moisture content affect aggregate stability and the importance of climate induced microbial shifts influence on microbially mediated soil (de)stabilisation. Static temperature and moisture content conditions significantly affected aggregate stability, however the effects varied dependent on soil texture. Increasing temperature significantly increased aggregate stability in clay loam aggregates, while moisture content significantly decreased aggregate stability in sandy loam aggregates. Multiple regression analysis showed that aggregate stability was best predicted by soil moisture content, microbial biomass carbon, gram-negative bacterial abundance and fungal abundance in the sandy loam. Temperature was the sole significant predictor in the clay loam. Aggregate stability was significantly lower under fluctuating conditions and higher under static conditions. Aggregate stability was not significantly different between fluctuating climate treatments representing summer and winter cycles under future emission scenarios. Although, these treatments did significantly affect the microbial community. Our results have implications for our current understanding of microbial function in terms of soil stabilisation, and the relationship between climate, aggregate stability and soil erodibility.</p>

Effects of tillage and direct drilling on soil properties during the growing season in a long-term barley mono-culture system

1977 ◽  
Vol 88 (2) ◽  
pp. 431-442 ◽  
Author(s):  
J. D. Pidgeon ◽  
B. D. Soane
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Management Practices ◽  
Sandy Loam ◽  
Spring Barley ◽  
Equilibrium Density ◽  
Zero Tillage ◽  
Clay Loam ◽  
Cone Resistance

SUMMARYSoil responses to deep (30–35 cm) and normal (15–20 cm) mouldboard ploughing, chisel ploughing and zero-tillage have been compared for 7 years in a field experiment growing continuous spring barley near Edinburgh. The soil was of variable texture, from moderately well-drained sandy loam overlying loam to imperfectly to poorly drained sandy clay loam overlying clay loam, classified as stagnogleyic brown earth to cambio stagnogley soil. Soils of this type derived from Carboniferous till are widely used for cereal production in south-east Scotland. Measurements of soil physical properties were made at crop emergence, midseason and at harvest to characterize seasonal and long-term responses to tillage and traffic. After the first 3 years bulk density responses varied little within or between seasons, showing a compacted horizon from 0–15 cm under zero-tillage and a looser horizon from 21–33 cm under deep ploughing compared with normal ploughing. Immediately below the depth of normal ploughing there was no difference in bulk density between this treatment and zero-tillage while in some years the chisel-ploughing treatment was denser. Moisture content responses on a weight basis, together with air-filled porosity responses, showed large differences between treatments particularly at the time of crop emergency, indicating substantial alterations in the soil profile hydrology. Expressed on a volume basis the increased moisture content near the surface under zero-tillage became more pronounced and the other effects disappeared. Cone resistance responses were proportionately larger than those for bulk density and showed one major difference in that below the depth of ploughing cone resistance was greater for zero-tillage than normal ploughing in the sixth and seventh seasons, but not previously. For bulk density, but probably not for cone resistance, there were no increases after the third season of zero-tillage, the soil reaching an equilibrium density for the current management practices and machinery usage.

scholarly journals Runoff and erosion as affected by tillage system and polyacrylamide in two sandy loam soils differing in silt and clay contents in semi-arid regions

2018 ◽  
Vol 37 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Nidal H. Abu-Hamdeh ◽  
◽  
Saleh M. Ismail ◽  
Samir G. Al-Solaimani Al-Solaimani ◽  
Randa I. Hatamleh ◽  
...  
Keyword(s):  
Arid Regions ◽  
Sandy Loam ◽  
Tillage System ◽  
Semi Arid

scholarly journals Micromycetes contaminating nuts used for food

Biologija ◽  
2015 ◽  
Vol 61 (3-4) ◽  
Author(s):  
Aurimas Krasauskas ◽  
Aurelija Paulauskienė ◽  
Živilė Tarasevičienė
Keyword(s):  
Moisture Content ◽  
Water Content ◽  
High Fat ◽  
Colony Forming Units ◽  
Colony Counting ◽  
Wide Range ◽  
Surface Spread

Nuts are one of the  most delicious and nutritious foods, but due to the  extremely high fat, protein and low water content they are quite refractory to spoilage by microorganisms. In this study a wide range of microorganisms was recorded. The samples were collected from 6 different markets in Kaunas, Lithuania. The  moisture content of nuts was determined by drying the samples in an oven at 103 (±2) °C temperature for 6 hours. Dilution plating (a surface-spread method) was used for colony counting. The  analyses of nut samples revealed that imported nuts were quite intensely contaminated with propagules of various fungi species. The  moisture content in the  nuts varied in dependence of their type and acquisition place. The  highest moisture content was observed in walnuts, 13.93%, while almost twice less in pistachio and hazelnuts, 6.38 and 6.76%, respectively. The least number of colony forming units (cfu) of fungi was detected in hazelnuts (9.11 × 10<sup>3</sup> cfu/g) followed by peanuts (11.46 × 10<sup>3</sup> cfu/g). In contrast, walnuts (20.90 × 10<sup>3</sup> cfu/g) represented the  highest infections of fungi. A  total of 8 different fungal genera (<i>Aspergillus</i>  spp. <i>Acremonium</i>  spp., <i>Cladosporium</i> spp., <i>Fusarium</i> spp., <i>Mucor</i> spp., <i>Rhizopus</i> spp., <i>Paecilomyces</i> spp., and <i>Penicillium</i> spp.) and 16 species were isolated. <i>Aspergillus, Mucor</i> and <i>Penicillium</i> genera were more frequently detected than other genera of fungi. <i>Aspergillus</i> spp. was found in the most investigated nut samples. The greatest diversity of micromycetes was detected in hazelnuts and walnuts.

Performance Evaluation of Surface Overlaid EN-42 Steel for Tillage Applications

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Jagseer Singh ◽  
Sukhpal Singh Chatha ◽  
Buta Singh Sidhu
Keyword(s):  
Weight Loss ◽  
Wear Rate ◽  
Moisture Content ◽  
Sandy Loam ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Wear Performance ◽  
Sandy Clay Loam ◽  
Actual Field ◽  
Loam Soil

Abstract Wear of tools is a key problem in the farming sector. The objective of this study was to evaluate the wear performance of untreated steel (EN-42) and two hardfacings, namely H1 and VB. Hardfacing H1 (0.86Cr0.22C) fall in the basic buildup iron–carbide alloy category and hardfacing VB (3.19Cr2.51C2.7Si) is categorized as martensitic alloy steel. Abrasive wear performance of untreated, as well as hardfaced steel specimens, was evaluated in the laboratory and actual field conditions. The tests were conducted in the laboratory, and actual field trials were conducted in sandy loam and sandy clay-loam soil. The performance of the untreated and hardfaced steel was analyzed using various techniques such as weight loss, microhardness, microstructure and scanning electron microscopy (SEM). The results revealed that H1 and VB overlaid steel exhibited better wear performance than the untreated steel, and the least wear-rate was found in sandy clay-loam soil. VB overlaid steel experienced lesser cumulative weight loss (g) and wear-rate (g/km) and thus displayed better abrasive wear behavior under all the conditions of the study. Further, it has been observed that the moisture content in soil exerts a stronger effect on ploughshare wear than soil type. For actual field conditions, untreated and overlaid ploughshares tested in sandy loam soil with low moisture content (0–3%) experienced almost three times higher wear-rate (4.078 g/km, 3.699 g/km, and 3.055 g/km for untreated, H1, and VB overlaid steel, respectively) than the same ploughshares tested in soil having high (14–17%) moisture content (1.296 g/km, 1.178 g/km, and 0.913 g/km for untreated, H1, and VB overlaid steel, respectively).

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