scholarly journals Studying Crop Yield Response to Supplemental Irrigation and the Spatial Heterogeneity of Soil Physical Attributes in a Humid Region

Agriculture ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 43 ◽  
Author(s):  
Amir Haghverdi ◽  
Brian Leib ◽  
Robert Washington-Allen ◽  
Wesley Wright ◽  
Somayeh Ghodsi ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Temporal Variability ◽  
Irrigation Management ◽  
Yield Response ◽  
Supplemental Irrigation ◽  
Plant Available Water

West Tennessee’s supplemental irrigation management at a field level is profoundly affected by the spatial heterogeneity of soil moisture and the temporal variability of weather. The introduction of precision farming techniques has enabled farmers to collect site-specific data that provide valuable quantitative information for effective irrigation management. Consequently, a two-year on-farm irrigation experiment in a 73 ha cotton field in west Tennessee was conducted and a variety of farming data were collected to understand the relationship between crop yields, the spatial heterogeneity of soil water content, and supplemental irrigation management. The soil water content showed higher correlations with soil textural information including sand (r = −0.9), silt (r = 0.85), and clay (r = 0.83) than with soil bulk density (r = −0.27). Spatial statistical analysis of the collected soil samples (i.e., 400 samples: 100 locations at four depths from 0–1 m) showed that soil texture and soil water content had clustered patterns within different depths, but BD mostly had random patterns. ECa maps tended to follow the same general spatial patterns as those for soil texture and water content. Overall, supplemental irrigation improved the cotton lint yield in comparison to rainfed throughout the two-year irrigation study, while the yield response to supplemental irrigation differed across the soil types. The yield increase due to irrigation was more pronounced for coarse-textured soils, while a yield reduction was observed when higher irrigation water was applied to fine-textured soils. In addition, in-season rainfall patterns had a profound impact on yield and crop response to supplemental irrigation regimes. The spatial analysis of the multiyear yield data revealed a substantial similarity between yield and plant-available water patterns. Consequently, variable rate irrigation guided with farming data seems to be the ideal management strategy to address field level spatial variability in plant-available water, as well as temporal variability in in-season rainfall patterns.

scholarly journals Evaluation of Improved Model to Accurately Monitor Soil Water Content

Water ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 3441
Author(s):  
Jingyu Ji ◽  
Junzeng Xu ◽  
Yixin Xiao ◽  
Yajun Luan
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Irrigation Management ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Matter Content ◽  
Improved Model

The accurate monitoring of soil water content during the growth of crops is of great importance to improve agricultural water use efficiency. The Campbell model is one of the most widely used models for monitoring soil moisture content from soil thermal conductivities in farmland, which always needs to be calibrated due to the lack of adequate original data and the limitation of measurement methods. To precisely predict the water content of complex soils using the Campbell model, this model was evaluated by investigating several factors, including soil texture, bulk density and organic matter. The comparison of the R2 and the reduced Chi-Sqr values, which were calculated by Origin, was conducted to calibrate the Campbell model calculated. In addition, combining factors of parameters, a new parameter named m related to soil texture and the organic matter was firstly introduced and the original fitting parameter, E, was improved to an expression related to clay fraction and the organic matter content in the improved model. The soil data collected from both the laboratory and the previous literature were used to assess the revised model. The results show that most of the R2 values of the improved model are >0.95, and the reduced Chi-Sqr values are <0.01, which presents a better matching performance compared to the original. It is concluded that the improved model provides more accurate monitoring of soil water content for water irrigation management.

scholarly journals INFLUÊNCIA DA TEXTURA E PROFUNDIDADE DO SOLO NA CALIBRAÇÃO DA SONDA DE NÊUTRONS

Irriga ◽  
1998 ◽  
Vol 3 (1) ◽  
pp. 6-12
Author(s):  
Reginaldo Ferreira Santos ◽  
Reimar Carlesso
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Correlation Coefficients ◽  
Regression Equations ◽  
Transparent Plastic ◽  
Neutron Probe ◽  
Calibration Curves ◽  
Santa Maria

INFLUÊNCIA DA TEXTURA E PROFUNDIDADE DO SOLO NA CALIBRAÇÃO DA SONDA DE NÊUTRONS   Reginaldo Ferreira SantosDepartamento de Engenharia Rural - UNESP, CP: 237 - CEP:18603 970, Botucatu, SP Reimar CarlessoDepartamento de. Engenharia da Universidade Federal de Santa Maria, - UFSM, Campus Universitário, CEP: 97119 900, Santa Maria - RS  1 RESUMO A sonda de nêutrons é um equipamento usado na determinação do conteúdo de água do solo baseado no espalhamento e atenuação de nêutrons rápidos. Para tanto, há necessidade de calibração no campo e, conseqüentemente, verificar a influência da textura e da profundidade do solo e determinar as curvas de calibração em relação ao conteúdo de umidade. O trabalho foi desenvolvido na Universidade Federal de Santa Maria em um conjunto de lisímetros, protegidos das precipitações pluviométricas com plástico transparente. Foram usados três solos de diferentes texturas e quatro repetições e em três profundidades (10, 30 e 50 cm) a partir da superfície do solo. Foram determinadas as equações de regressão lineares entre as contagens propiciadas pela sonda e o conteúdo de umidade do solo respectivos pelo método gravimétrico. Os resultados demonstraram que houve interferência da textura e da profundidade do solo, analisados conjuntamente, nas curvas de calibração, sendo que os valores observados e os estimados variaram entre 0,02 e 0,06 cm3/ cm3 do conteúdo de água do solo e os coeficientes de correlação foram 0,86, 0,95 e 0,89 para os solos de textura argilosa, franco-argilo-siltoso e franco-arenoso, respectivamente. Já para os fatores textura e profundidade dos solos, analisados separadamente, as diferenças entre os valores observados no campo e os estimados, variaram entre 0,0 e 0,02 cm31cm3 do conteúdo de água do solo e apresentaram coeficientes de correlação entre 0,97 e 1,0. UNITERMOS: sonda de nêutrons. umidade do solo. textura e profundidade do solo  SANTOS, R.F., CARLESSO, R. Soil texture and depth influence on the neutron probe calibration   2 SUMMARY  The neutron probe is an equipment used on determination of the soil water content, based on the fast neutron attenuation. Therefore, there is a calibration need in the field and, consequently, to verify the soil texture and depth influence for to determining the calibration curves in relation to the water content. The study was developed at Santa Maria's Federal University in a lisímeter group, protected from the rains with transparent plastic. Three different soil textures, three depths (10, 30 and 50 cm from the soil surface) and four replicates were used. Linear regression equations between neutron counts and soil water contents were made. The results showed that there was interference of the texture and depth of the soil, analyzed jointly, on the calibration curves, and the observed and estimated values varied from 0,02 to 0,06 cm3 / cm3 of the soil water content and the correlation coefficients were 0,86, 0,95 and 0,89 for clayay, franc-silt-clayay and franc-sandy, respectively. For soil texture and depth, analyzed separately, the differences among the values observed in the field and the estimated ones, varied from 0,0 to 0,02 cm3/cm3 soil water content and presented correlation coefficients between 0,97 and 1,0. KEYWORDS: neutron probe, soil water content, soil texture and depth.

scholarly journals Overstory–Understory Vegetation Cover and Soil Water Content Observations in Western Juniper Woodlands: A Paired Watershed Study in Central Oregon, USA

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 151 ◽  
Author(s):  
Grace Ray ◽  
Carlos G. Ochoa ◽  
Tim Deboodt ◽  
Ricardo Mata-Gonzalez
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Soil Texture ◽  
Canopy Cover ◽  
Understory Vegetation ◽  
Watershed Scale ◽  
Shrub Cover ◽  
Western Juniper ◽  
Tree Canopy Cover

The effects of western juniper (Juniperus occidentalis) control on understory vegetation and soil water content were studied at the watershed-scale. Seasonal differences in topsoil (12 cm) water content, as affected by vegetation structure and soil texture, were evaluated in a 96-ha untreated watershed and in a 116-ha watershed where 90% juniper was removed in 2005. A watershed-scale characterization of vegetation canopy cover and soil texture was completed to determine some of the potential driving factors influencing topsoil water content fluctuations throughout dry and wet seasons for approximately one year (2014–2015). We found greater perennial grass, annual grass, and shrub cover in the treated watershed. Forb cover was no different between watersheds, and as expected, tree canopy cover was greater in the untreated watershed. Results also show that on average, topsoil water content was 1% to 3% greater in the treated watershed. The exception was during one of the wettest months (March) evaluated, when soil water content in the untreated watershed exceeded that of the treated by <2%. It was noted that soil water content levels that accumulated in areas near valley bottoms and streams were greater in the treated watershed than in the untreated toward the end of the study in late spring. This is consistent with results obtained from a more recent study where we documented an increase in subsurface flow residence time in the treated watershed. Overall, even though average soil water content differences between watersheds were not starkly different, the fact that more herbaceous vegetation and shrub cover were found in the treated watershed led us to conclude that the long-term effects of juniper removal on soil water content redistribution throughout the landscape may be beneficial towards restoring important ecohydrologic connections in these semiarid ecosystems of central Oregon.

Time series outlier and intervention analysis: Irrigation management influences on soil water content in silty loam soil

2012 ◽  
Vol 111 ◽  
pp. 105-114 ◽  
Author(s):  
Basem Aljoumani ◽  
Jose A. Sànchez-Espigares ◽  
Nuria Cañameras ◽  
Ramon Josa ◽  
Joaquim Monserrat
Keyword(s):  
Time Series ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Irrigation Management ◽  
Intervention Analysis ◽  
Silty Loam ◽  
Loam Soil

Fractal Description of the Spatial and Temporal Variability of Soil Water Content Across an Agricultural Field

Soil Science ◽  
2012 ◽  
Vol 177 (2) ◽  
pp. 131-138 ◽  
Author(s):  
Eva Vidal-Vázquez ◽  
Jorge Paz-Ferreiro ◽  
Sidney Vieira ◽  
George Topp ◽  
José Miranda ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Variability ◽  
Spatial And Temporal Variability ◽  
Agricultural Field ◽  
Fractal Description

Spatio-temporal variability behavior of land surface soil water content in shrub- and grass-land

Geoderma ◽  
2011 ◽  
Vol 162 (3-4) ◽  
pp. 260-272 ◽  
Author(s):  
Wei Hu ◽  
Mingan Shao ◽  
Fengpeng Han ◽  
Klaus Reichardt
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Temporal Variability ◽  
Land Surface ◽  
Surface Soil ◽  
Grass Land ◽  
Spatio Temporal
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