OBSERVED AND ESTIMATED SEASONAL SOIL WATER VARIATIONS UNDER NONIRRIGATED SOD

1969 ◽  
Vol 49 (2) ◽  
pp. 181-188 ◽  
Author(s):  
W. Baier
Keyword(s):  
Soil Water ◽  
Water Budget ◽  
Soil Classification ◽  
Coefficient Of Determination ◽  
Standard Errors ◽  
Climatic Data ◽  
Wet Season ◽  
Total Period ◽  
Plant Soil ◽  
Available Soil Moisture

Variations of soil water content under nonirrigated sod at Ottawa during 10 seasons were analyzed using 5-day means of daily resistance readings from Colman units. A meteorological water budget making use of standard climatic data and accounting for physical properties of the soil provided estimates of soil water which resembled the measured values. The coefficient of determination for 5-day means of observed soil water, correlated with the estimates, varied from 0.34 in a wet season to 0.84 in a dry season, and was 0.73 over the whole 10-year period. Standard errors of estimates were between 4 and 25% of the seasonal mean of available soil moisture, and 15% for the total period. It was concluded that, for climatic and soil classification purposes, estimates from this meteorological budgeting technique are sufficiently accurate to be used for interpreting plant–soil–water interactions over past periods, for which climatological but not soil water observations are available.

A CLIMATIC MOISTURE INDEX FOR LAND AND SOIL CLASSIFICATION IN CANADA

1970 ◽  
Vol 50 (3) ◽  
pp. 291-301 ◽  
Author(s):  
W. K. SLY
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Soil Classification ◽  
Climatic Variables ◽  
Climatic Data ◽  
Moisture Index ◽  
Annual Crops ◽  
Water Conditions ◽  
Soil Water Conditions ◽  
Irrigation Requirements

Recent advances in the application of computer techniques for determining irrigation requirements from climatic data have made possible the development of a climatic moisture index to supplement conventional methods used in land and soil classification. The index approximates the ability of precipitation to provide the water required by annual crops if their production is not limited by water stress. Standardization of the non-climatic variables involved in its determination does not unduly restrict the range of soil textures and spring soil water conditions to which it applies. The values of the index in the various climatic regimes across the country are shown and their use in providing supplemental information for land and soil classification is indicated.

scholarly journals Integrating MODIS images in a water budget model for dynamic functioning and drought simulation of a Mediterranean forest in Tunisia

2012 ◽  
Vol 9 (5) ◽  
pp. 6251-6284 ◽  
Author(s):  
H. Chakroun ◽  
F. Mouillot ◽  
M. Nouri ◽  
Z. Nasr
Keyword(s):  
Soil Water ◽  
Water Budget ◽  
Regional Scale ◽  
Field Capacity ◽  
Stress Index ◽  
Climatic Data ◽  
Natural Ecosystem ◽  
Stress Monitoring ◽  
Budget Model ◽  
Vegetation Stress

Abstract. The use of remote sensing at different spatio-temporal resolutions is being common during the last decades since sensors offer many inputs to water budget estimation. Various water balance models use the LAI as a parameter for accounting water interception, evapotranspiration, runoff and available ground water. The objective of the present work is to improve vegetation stress monitoring at regional scale for a natural forested ecosystem. LAI-MODIS and spatialized vegetation, soil and climatic data have been integrated in a water budget model that simulates evapotranspiration and soil water content at daily step. We first explore LAI-MODIS in the specific context of Mediterranean natural ecosystem. Results showed that despite coarse resolution of LAI-MODIS product (1 km), it was possible to discriminate evergreen and coniferous vegetation and that LAI values are influenced by underlying soil capacity of water holding. The dynamic of vegetation has been integrated into the water budget model by weekly varying LAI-MODIS. Results of simulations were analysed in terms of actual evapotranspoiration, deficit of soil water to field capacity and vegetation stress index based on actual and potential evapotranspiration. Comparing dynamic LAI variation, afforded by MODIS, to a hypothetic constant LAI all over the year correspond to 30% of fAPAR increase. A sensitivity analysis of simulation outputs to this fAPAR variation reveals that increase of both deficit of soil water to field capacity and stress index are respectively 18% and 27%, (in terms of RMSE, these variations are respectively 1258 mm yr−1 and 11 days yr−1). These results are consistent with previous studies led at local scale showing that LAI increase is accompanied by stress conditions increase in Mediterranean natural ecosystems. In this study, we also showed that spatial modelisation of drought conditions based on water budget simulations is an adequate tool for quantifying expositions of different species to stress and for analysing most influent factors on ecosystem vulnerability to drought.

Analyses of groundwater flow and plant evapotranspiration in a vegetated soil slope

2013 ◽  
Vol 50 (12) ◽  
pp. 1204-1218 ◽  
Author(s):  
A.K. Leung ◽  
C.W.W. Ng
Keyword(s):  
Groundwater Flow ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Root Water Uptake ◽  
Dry Season ◽  
Climatic Data ◽  
Wet Season ◽  
Soil Slopes ◽  
Transient Seepage

Understanding seasonal hydrogeological responses of vegetated soil slopes is vital to slope stability because pore-water pressure (PWP) varies from positive values upon rainfall in wet seasons to negative values upon plant evapotranspiration (ET) in dry seasons. There are, however, few case histories that report seasonal performance of vegetated soil slopes. In this study, a vegetated slope situated in Hong Kong was instrumented to analyse (i) groundwater flow during rainfall in the wet season and (ii) effects of plant ET on PWP in the dry season. Two- and three-dimensional anisotropic transient seepage analyses are conducted to identify groundwater flow mechanism(s) during a heavy rainstorm. Through water and energy balance calculations, measured plant-induced suction is interpreted with plant characteristic and climatic data. During the rainstorm, substantial recharge of the groundwater table was recorded, likely due to preferential water flow along relict joints and three-dimensional cross-slope groundwater flow. During the dry season, the peak suction induced by plant ET is up to 200 kPa and the depth of influence is shallower than 200% of the root depth. For the range of suctions monitored, root-water uptake is revealed to have been restricted by suction not very significantly and was driven mainly by the climatic variation.

scholarly journals COMPARAÇÃO ENTRE MÉTODOS DE ESTIMATIVA DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA PARA O MUNICÍPIO DE PETROLINA, PE

Irriga ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Roberta Daniela Silva Santos ◽  
Marcello Henryque Costa de Souza ◽  
Regiane De Carvalho Bispo ◽  
Kevim Muniz Ventura ◽  
Luis Henrique Bassoi
Keyword(s):  
Reference Evapotranspiration ◽  
Estimation Method ◽  
Arid Climate ◽  
Estimation Methods ◽  
Coefficient Of Determination ◽  
Climatic Data ◽  
Test Field ◽  
Rating Method ◽  
And Performance ◽  
Semi Arid

COMPARAÇÃO ENTRE MÉTODOS DE ESTIMATIVA DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA PARA O MUNICÍPIO DE PETROLINA, PE  ROBERTA DANIELA DA SILVA SANTOS1; MARCELLO HENRYQUE COSTA DE SOUZA1; REGIANE DE CARVALHO BISPO1; KEVIM MUNIZ VENTURA1 E LUÍS HENRIQUE BASSOI2 1Programa de Pós-Graduação em Irrigação e Drenagem, Universidade Estadual Paulista “Júlio de Mesquita Filho”- UNESP/FCA, Rua Dr. José Barbosa de Barros, 1780, Botucatu, SP, [email protected], [email protected], [email protected], [email protected] Embrapa Instrumentação, São Carlos, SP, [email protected]  1 RESUMO O conhecimento da evapotranspiração é vital na determinação das necessidades hídricas de uma cultura. Diante disso, o objetivo deste trabalho foi comparar o desempenho de sete métodos de estimativa da evapotranspiração de referência em relação ao método de Penman-Monteith, adotado como padrão, para o município de Petrolina, PE. Foram utilizados dados climáticos diários de 2004 a 2015, para estimar da ET0, obtidos na estação meteorológica automática do Campo Experimental de Bebedouro da Embrapa Semiárido, Petrolina, PE. Os indicadores estatísticos utilizados na avaliação foram: coeficiente de determinação (r²); coeficiente de correlação (r); índice de concordância (d) e índice de desempenho (c). Os valores do r² mostraram que o método de estimativa que melhor se ajustou ao método de Penman-Monteith foi o de Ivanov (0,73); seguido pelos métodos de Jensen-Haise (0,64); Makkink e Priestley-Taylor (0,63); Villa Nova (0,62); Hargreaves e Samani (0,53) e Hamon (0,45). No entanto, com relação ao do índice “c”, Hamon foi classificado com “péssimo”; Makkink como “mau”; Hargreaves e Samani e Villa Nova como “sofrível”; Ivanov e Priestley-Taylor como “mediano”; e Jensen-Haise como “bom”. Esse último método foi considerado como o de melhor classificação de desempenho. Palavras-chave: Penman-Monteith, correlação, semiárido.  SANTOS, R. D. S.; SOUZA, M. H. C.; BISPO, R. de C.; VENTURA, K. M.; BASSOI, L. H.METHOD-COMPARISON STUDY TO ESTIMATE THE REFERENCE EVAPOTRANSPIRATION IN PETROLINA, PE  2 ABSTRACT The knowledge on evapotranspiration is vital in determining the water requirements of a crop. Therefore, this paper aims to compare the performance of seven of estimation methods for the reference evapotranspiration in relation to the Penman-Monteith method, adopted as standard, for the municipality of Petrolina, state of Pernambuco, Brazil. We used daily climatic data from 2004 to 2015 to estimate the ET0 coefficient, obtained in the automatic weather station of the Test Field in Bebedouro, Embrapa in the Semi-arid climate. The statistical indicators used in the evaluation were: coefficient of determination (r²), correlation coefficient (r), agreement index (d) and performance index (c). The r2 values showed that the estimation method that best fitted to the Penman-Monteith method was Ivanov's (0.73), followed by Jensen-Haise (0.64), Makkink and Priestley-Taylor (0.63), Villa Nova (0.62), Hargreaves and Samani (0.53) and Hamon (0.45) methods. However, in relation to the index "c", Hamon was classified as "very poor"; Makkink as "poor"; Hargreaves and Samani and Villa Nova as "tolerable"; Ivanov and Priestley-Taylor as "medium"; and Jensen-Haise as "good". The last one was considered as the best performance rating method. Keywords: Penman-Monteith, correlation, semi-arid climate.

scholarly journals Rooting Depth, Growth and Yield of Sorghum as Affected by Soil Water Availability in an Ultisol and an Oxisol

1969 ◽  
Vol 60 ◽  
pp. 329-335
Author(s):  
A. Wahab ◽  
H. Talleyrand ◽  
M. A. Lugo-López
Keyword(s):  
Soil Moisture ◽  
Plant Growth ◽  
Soil Water ◽  
Grain Filling ◽  
Growth And Yield ◽  
Rooting Depth ◽  
Weather Factors ◽  
Soil Water Tension ◽  
Available Soil Moisture ◽  
Water Tension

Grain and stover yields of RS 671 grain sorghum were measured at Barranquitas in an Oxisol and at Corozal in an Ultisol. Measurements were made of weather factors, soil moisture content and tension, plant growth, water deficits and rooting depths. At each site a plot was irrigated as often as necessary to maintain a soil water tension of less than 1 bar. Nonirrigated plots at Corozal were watered whenever necessary to prevent plants from wilting permanently. During a prolonged drought and at grain filling, sorghum extracted water in the Oxisol to a depth of 120 cm. Plants became water stressed after the soil water tension at a depth of 90 cm reached 15 bars. In the Ultisol, sorghum plants were unable to effectively extract available soil moisture at depths below 45 cm. Both plant growth and grain yield were greater in the Oxisol than in the Ultisol. The relative soil compaction of the Ultisol was greater than that of the Oxisol.

scholarly journals Exploring the Predictability of 30-Day Extreme Precipitation Occurrence Using a Global SST–SLP Correlation Network

2016 ◽  
Vol 29 (3) ◽  
pp. 1013-1029 ◽  
Author(s):  
Mengqian Lu ◽  
Upmanu Lall ◽  
Jaya Kawale ◽  
Stefan Liess ◽  
Vipin Kumar
Keyword(s):  
Extreme Precipitation ◽  
Time Lag ◽  
Principal Component Regression ◽  
Principal Component ◽  
Correlation Network ◽  
Climatic Data ◽  
Wet Season ◽  
Predictive Skill ◽  
Correlation Networks ◽  
Time Lagged

Abstract Correlation networks identified from financial, genomic, ecological, epidemiological, social, and climatic data are being used to provide useful topological insights into the structure of high-dimensional data. Strong convection over the oceans and the atmospheric moisture transport and flow convergence indicated by atmospheric pressure fields may determine where and when extreme precipitation occurs. Here, the spatiotemporal relationship among sea surface temperature (SST), sea level pressure (SLP), and extreme global precipitation is explored using a graph-based approach that uses the concept of reciprocity to generate cluster pairs of locations with similar spatiotemporal patterns at any time lag. A global time-lagged relationship between pentad SST anomalies and pentad SLP anomalies is investigated to understand the linkages and influence of the slowly changing oceanic boundary conditions on the development of the global atmospheric circulation. This study explores the use of this correlation network to predict extreme precipitation globally over the next 30 days, using a logistic principal component regression on the strong global dipoles found between SST and SLP. Predictive skill under cross validation and blind prediction for the occurrence of 30-day precipitation that is higher than the 90th percentile of days in the wet season is indicated for the selected global regions considered.

scholarly journals Plant-soil-water interactions: Implications from U-Th-Ra isotope analysis in soils, soil solutions and vegetation (Strengbach CZO, France)

2019 ◽  
Vol 259 ◽  
pp. 188-210 ◽  
Author(s):  
François Chabaux ◽  
Peter Stille ◽  
Jonathan Prunier ◽  
Sophie Gangloff ◽  
Damien Lemarchand ◽  
...  
Keyword(s):  
Soil Water ◽  
Isotope Analysis ◽  
Plant Soil ◽  
Soil Solutions

scholarly journals Pedotransfer functions of soil water properties to estimate the S-index

2018 ◽  
Vol 22 (7) ◽  
pp. 465-470
Author(s):  
João H. Caviglione
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Field Conditions ◽  
Pedotransfer Functions ◽  
Water Retention Curve ◽  
Coefficient Of Determination ◽  
Native Forest ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Physical Quality

ABSTRACT One big challenge for soil science is to translate existing data into data that is needed. Pedotransfer functions have been proposed for this purpose and they can be point or parametric when estimating the water retention characteristics. Many indicators of soil physical quality have been proposed, including the S-Index proposed by Dexter. The objective of this study was to assess the use of pedotransfer functions for soil water retention to estimate the S-index under field conditions in the diversity of soils of the Paraná state. Soil samples were collected from 36 sites with textures ranging from sandy to heavy clay in the layers of 0-0.10 and 0.10-0.20 m and under two conditions (native forest and cultivated soil). Water content at six matric potentials, bulk density and contents of clay, sand and silt were determined. Soil-water retention curve was fitted by the van Genuchten-Mualem model and the S-index was calculated. S-index was estimated from water retention curves obtained by the pedotransfer function of Tomasella (point and parametric). Although the coefficient of determination varied from 0.759 to 0.895, modeling efficiency was negative and the regression coefficient between observed and predicted data was different from 1 in all comparisons. Under field conditions in the soil diversity of the Paraná state, restrictions were found in S-index estimation using the evaluated pedotransfer functions.

Sign in / Sign up

Export Citation Format

Share Document