Root-Zone Soil Water Balance and Sunflower Yield under Deficit Irrigated in Zambia

Precise, accurate knowledge of percolation is key to reliable determination of soil water balance and a crop’s water-use efficiency. This work evaluated an approach to estimate the amount of water percolated in the root zone using soil water content (SWC) data measured at different time intervals. The approach was based on the difference of soil water content within and below the effective root zone of banana plants at different time intervals. A drainage lysimeter was used to compare the measured and estimated percolation data. The approach was then used in a banana orchard under drip and micro sprinkler irrigation, with and without the use of mulch. The soil water storage in the banana’s root zone was evaluated within a two-dimensional soil profile with time domain reflectometry (TDR). Mean percolation measured in the lysimeters did not differ from the approach’s estimates using intervals between SWC readings equal to or longer than 6 h from the end of an irrigation event. Percolation estimates under drip and micro sprinkler irrigation in the field, with and without mulch, were consistent with those measured in the lysimeters, considering the 6-h interval of SWC measurements. Percolation was greater under the drip irrigation system with mulch. The amount of water percolated was not influenced by the presence of mulch under the micro sprinkler system. Keywords: localized irrigation, soil water balance, soil water content sensor.

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Modeling the monthly mean soil-water balance with a statistical-dynamical ecohydrology model as coupled to a two-component canopy model

Hydrology and Earth System Sciences ◽

10.5194/hess-14-2099-2010 ◽

2010 ◽

Vol 14 (10) ◽

pp. 2099-2120 ◽

Cited By ~ 12

Author(s):

J. P. Kochendorfer ◽

J. A. Ramírez

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Water Balance ◽

Soil Water ◽

Soil Texture ◽

Root Zone ◽

Soil Water Balance ◽

Area Index ◽

Two Component ◽

Canopy Model

Abstract. The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using separate potential rates of transpiration and bare-soil evaporation. Those potential rates, along with the rate of evaporation from canopy interception, are calculated using the two-component Shuttleworth-Wallace (1985) canopy model. In addition, the soil column is divided into two layers, with the upper layer representing the dynamic root zone. The resulting ability to account for changes in root-zone water storage allows for implementation at the monthly timescale. This new version of the Eagleson model is coined the Statistical-Dynamical Ecohydrology Model (SDEM). The ability of the SDEM to capture the seasonal dynamics of the local-scale soil-water balance is demonstrated for two grassland sites in the US Great Plains. Sensitivity of the results to variations in peak green leaf area index (LAI) suggests that the mean peak green LAI is determined by some minimum in root zone soil moisture during the growing season. That minimum appears to be close to the soil matric potential at which the dominant grass species begins to experience water stress and well above the wilting point, thereby suggesting an ecological optimality hypothesis in which the need to avoid water-stress-induced leaf abscission is balanced by the maximization of carbon assimilation (and associated transpiration). Finally, analysis of the sensitivity of model-determined peak green LAI to soil texture shows that the coupled model is able to reproduce the so-called "inverse texture effect", which consists of the observation that natural vegetation in dry climates tends to be most productive in sandier soils despite their lower water holding capacity. Although the determination of LAI based on complete or near-complete utilization of soil moisture is not a new approach in ecohydrology, this paper demonstrates its use for the first time with a new monthly statistical-dynamical model of the water balance. Accordingly, the SDEM provides a new framework for studying the controls of soil texture and climate on vegetation density and evapotranspiration.

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THREE-DIMENSIONAL WATER EXTRACTION IN THE ROOT ZONE OF DRIP-IRRIGATED TOMATO

Irriga ◽

10.15809/irriga.2018v23n4p667-678 ◽

2018 ◽

Vol 23 (4) ◽

pp. 667-678

Author(s):

Alisson Silva ◽

Valéria Almeida Jatobá ◽

Francisco Airderson Lima Nascimento ◽

Allan Radax Freitas Campos ◽

Jilcélio Almeida

Keyword(s):

Water Balance ◽

Water Content ◽

Soil Water ◽

Root Zone ◽

Irrigation Management ◽

Three Dimensional ◽

Water Extraction ◽

Soil Water Balance ◽

Crop Evapotranspiration ◽

Tomato Crop

THREE-DIMENSIONAL WATER EXTRACTION IN THE ROOT ZONE OF DRIP-IRRIGATED TOMATO FRANCISCO AIRDESSON LIMA DO NASCIMENTO¹; ALISSON JADAVI PEREIRA DA SILA²; VALERIA ALMEIDA JATOBA³; ALLAN RADAX FREITAS CAMPOS4 E JILCÉLIO NUNES DE ALMEIDA³ 1- Doutorando em Engenharia Agrícola pela Universidade Federal do Recôncavo da Bahia (UFRB), Rua Rui Barbosa, 710, Centro, 44.380-000, Cruz das Almas, Bahia, Brasil, [email protected]; 2- Professor Doutor do Intituto Federal de Educação, Ciência e Tecnologia Baiano (IF Baiano), Campus Governador Mangabeira, Rua Waldemar Mascarenhas, 656, Centro, 44350-000, Gov. Mangabeira, Bahia, Brasil, [email protected]; 3- Licenciado(a) em Ciências Agrárias pelo Intituto Federal de Educação, Ciência e Tecnologia Baiano (IF Baiano), Campus Senhor do Bonfim, Estrada da Igara, s/n, Zona Rural, 48970-000, Senhor do Bonfim, Bahia, Brasil, [email protected]; 4- Doutor em Engenharia Agrícola pela Universidade Federal do Recôncavo da Bahia (URFB), Rua Rui Barbosa, 710, Centro, 44.380-000, Cruz das Almas, Bahia, Brasil, [email protected]. 1 ABSTRACT Soil water sensing is a common alternative for irrigation management. Due to the difficulty to determine the spatial-temporal variability of water extraction (WE) in the root zone of a crop it is still arbitrary the definition of number and position of water content sensors to be installed for irrigation management purposes. The main objectives of this work are to use Time Domain Reflectometry (TDR) to detail – in three-dimensions – WE in the root zone of tomato plants cultivated in covered and uncovered soil; and, to evaluate if there are differences in the values of tomato crop evapotranspiration (ET) determined through soil water balance (SWB) with one, two, three and four TDR probe monitoring profiles. The study was carried out under semiarid condition. Tomatoes were grown in the field and two drainage lysimeters were installed in the center of cultivation area. In one lysimeter the soil surface was maintained uncovered, while in the other the soil surface was covered with a black plastic canvas. Eight TDR probes were installed within each lysimeter for the three-dimensional monitoring of soil water content (SWC). WE was estimated with SWC data. It was found that WE in tomato root zone is more intense in regions of greater water availability in the soil, i.e, on wet wet bulb formed inside the soil. There are no differences in the estimation of tomato crop evapotranspiration through soil water balance varying the position of two-dimensional soil water content monitoring. However, when soil water balance is performed in three-dimensions there may be large differences in daily tomato crop evapotranspiration estimation compared to the two-dimensional soil water balance. Keywords: tomato, sensor placement, irrigation management. NASCIMENTO, F.A. L.; SILVA, A. J.P.; JATOBA, V.A.; CAMPOS, A.R.F.; ALMEIDA, J.N EXTRAÇÃO TRI-DIMENSIONAL DE ÁGUA NA ZONA RADICULAR DO TOMATEIRO IRRIGADO POR GOTEJAMENTO 2 RESUMO O sensoriamento de água no solo é uma comum alternativa para o manejo da irrigação. Devido à dificuldade em se determinar a variabilidade espaço-temporal da extração de água na zona radicular dos cultivos, ainda é arbitrária a definição do número e posicionamento de sensores de água no solo a serem instalados para fins de manejo de irrigação. Diante disso, objetivou-se com o referido trabalho utilizar a Reflectometria no Domínio do Tempo (TDR) para detalhar, em três dimensões, a extração de água pelo tomateiro em cultivo com solo coberto e descoberto, e verificar se existem diferenças nos valores de evapotranspiração da cultura determinados pelo balanço de água no solo com um, dois, três e quatro perfis de monitoramento. O trabalho foi conduzido em condição semiárida nas fases de floração e frutificação da cultura. Montou-se um sistema de aquisição de dados, composto por uma TDR 100 e um datalogger modelo CR 800 para leitura e armazenamento de dados do conteúdo de água no solo. Dois lisímetros de drenagem foram instalados no centro de uma área de cultivo, sendo um mantido com a superfície do solo coberto com lona plástica. Em cada lisímetro, foram distribuídas oito sondas de TDR de modo a formar quatro perfis de monitoramento na zona radicular do tomateiro. A extração de água da zona radicular do tomateiro é mais intensa na região de maior disponibilidade de água, especificamente, na região do bulbo molhado. Não há diferença nos valores de evapotranspiração do tomateiro estimado variando-se a posição do perfil bi-dimensional. Entratanto, ao se comparar valores diários de evapotranspiração do tomateiro estimado com balanço de água no solo realizado em duas e três-dimensões, verificou-se haver largas diferenças. Palavras-chave: tomate, extração de água no solo, manejo da irrigação.

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Modeling the monthly mean soil-water balance with a statistical-dynamical ecohydrology model as coupled to a two-component canopy model

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-5-579-2008 ◽

2008 ◽

Vol 5 (2) ◽

pp. 579-648

Author(s):

J. P. Kochendorfer ◽

J. A. Ramírez

Keyword(s):

Soil Moisture ◽

Water Stress ◽

Water Balance ◽

Soil Water ◽

Soil Texture ◽

Root Zone ◽

Soil Water Balance ◽

Area Index ◽

Two Component ◽

Canopy Model

Abstract. The statistical-dynamical annual water balance model of Eagleson (1978) is a pioneering work in the analysis of climate, soil and vegetation interactions. This paper describes several enhancements and modifications to the model that improve its physical realism at the expense of its mathematical elegance and analytical tractability. In particular, the analytical solutions for the root zone fluxes are re-derived using separate potential rates of transpiration and bare-soil evaporation. Those potential rates, along with the rate of evaporation from canopy interception, are calculated using the two-component Shuttleworth-Wallace (1985) canopy model. In addition, the soil column is divided into two layers, with the upper layer representing the dynamic root zone. The resulting ability to account for changes in root-zone water storage allows for implementation at the monthly timescale. This new version of the Eagleson model is coined the Statistical-Dynamical Ecohydrology Model (SDEM). The ability of the SDEM to capture the seasonal dynamics of the local-scale soil-water balance is demonstrated for two grassland sites in the US Great Plains. Sensitivity of the results to variations in peak green Leaf Area Index (LAI) suggests that the mean peak green LAI is determined by some minimum in root zone soil moisture during the growing season. That minimum appears to be close to the soil matric potential at which the dominant grass species begins to experience water stress and well above the wilting point, thereby suggesting an ecological optimality hypothesis in which the need to avoid water-stress-induced leaf abscission is balanced by the maximization of carbon assimilation (and associated transpiration). Finally, analysis of the sensitivity of model-determined peak green LAI to soil texture shows that the coupled model is able to reproduce the so-called "inverse texture effect", which consists of the observation that natural vegetation in dry climates tends to be most productive in sandier soils despite their lower water holding capacity. Although the determination of LAI based on near-complete utilization of soil moisture is not a new approach in ecohydrology, this paper demonstrates its use for the first time with a new monthly statistical-dynamical model of the water balance. Accordingly, the SDEM provides a new framework for studying the controls of soil texture and climate on vegetation density and evapotranspiration.

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Influence of Rice Husk - Mulch on Soil Water Balance Components under Sorghum and Millet Crops in Maiduguri, Semi Arid Northeast Nigeria

Journal of Experimental Agriculture International ◽

10.9734/jeai/2019/v33i430150 ◽

2019 ◽

pp. 1-7

Author(s):

P. C. Eze ◽

A. J. Odofin ◽

I. N. Onyekwere ◽

J. J. Musa ◽

P. A. Tsado

Keyword(s):

Moisture Content ◽

Water Balance ◽

Soil Water ◽

Rice Husk ◽

Root Zone ◽

Soil Water Balance ◽

Annual Rainfall ◽

Crop Evapotranspiration ◽

Water Balance Components ◽

Moisture Storage

A 2 x 3 factorial experiment was conducted at two sites in Maiduguri, Borno State during the 2009 cropping season. The objective was to evaluate the influence of rice husk-mulch on soil water balance components under sorghum and millet crops. The treatments comprised of two test crops (sorghum and millet) and three rates of application (0, 10 and 15 t ha-1) of rice husk mulch, fitted in a split-plot design. The test crops were assigned to the main plot, while the mulch application rates were assigned to the sub-plot. The treatments were replicated three times. The components of soil water balance determined were annual rainfall, moisture storage within sorghum and millet root zone, drainage below crop root zone and seasonal crop evapotranspiration. Profile moisture content was measured weekly with the aid of a neutron probe installed at a depth of 2.0 m using access tubes. Also, soil (0 – 30 cm depth) moisture content was determined gravimetrically on weekly basis. Rainfall was measured using a manual rain gauge installed at each of the two sites. Findings in this study indicated that, under the prevailing circumstances, annual rainfall was lower than the amount observed over a ten-year period in Maiduguri. Consequently, soil moisture storage, drainage and seasonal crop evapotranspiration generally declined. An average of over 90 % of this low annual rainfall was lost as seasonal crop evapotranspiration. Sorghum plots stored higher moisture within the root zone, had higher drainage and lower seasonal evapotranspiration than millet plots. Moisture storage and drainage increased with increasing mulch application rate, while, seasonal crop evapotranspiration decreased with it.

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In situ unsaturated zone water stable isotope (<sup>2</sup>H and <sup>18</sup>O) measurements in semi-arid environments: a soil water balance

Hydrology and Earth System Sciences ◽

10.5194/hess-20-715-2016 ◽

2016 ◽

Vol 20 (2) ◽

pp. 715-731 ◽

Cited By ~ 46

Author(s):

Marcel Gaj ◽

Matthias Beyer ◽

Paul Koeniger ◽

Heike Wanke ◽

Josefina Hamutoko ◽

...

Keyword(s):

Stable Isotopes ◽

Water Balance ◽

Soil Water ◽

Root Zone ◽

Soil Water Balance ◽

Vacuum Extraction ◽

Rain Event ◽

Arid Environments ◽

Semi Arid

Abstract. Stable isotopes (deuterium, 2H, and oxygen-18, 18O) of soil water were measured in the field using a liquid water isotope analyzer (tunable off-axis integrated cavity output spectroscope, OA-ICOS, LGR) and commercially available soil gas probes (BGL-30, UMS, Munich) in the semi-arid Cuvelai–Etosha Basin (CEB), Namibia. Results support the applicability of an in situ measurement system for the determination of stable isotopes in soil pore water. High spatial and temporal resolution was achieved in the study area with reasonable accuracy and measurements were in agreement with laboratory-based cryogenic vacuum extraction and subsequent cavity ring-down laser spectroscopic isotope analysis (CRDS, L2120-i, Picarro Inc.). After drift and span correction of the in situ isotope data, precision for over 140 measurements taken during two consecutive field campaigns (June and November 2014) was 1.8 and 0.48 ‰ for δ2H and δ18O, respectively. Mean measurement trueness is determined using quality check standards and was 5 and 0.3 ‰ for δ2H and δ18O, respectively. The isotope depth profiles are used quantitatively to calculate a soil water balance. The contribution of transpiration to total evapotranspiration ranged between 72 and 92 %. Shortly after a rain event, the contribution of transpiration was much lower, at 35 to 50 %. Potential limitations of such an in situ system are related to environmental conditions which could be minimized by using a temperature-controlled chamber for the laser spectrometer. Further, the applicability of the system using previously oven-dried soil material might be limited by physicochemical soil properties (i.e., clay minerals). Uncertainty in the in situ system is suggested to be reduced by improving the calibration procedure and further studying fractionation effects influencing the isotope ratios in the soil water, especially at low water contents. Furthermore, the influence of soil-respired CO2 on isotope values within the root zone could not be deduced from the data.

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Comparative evaluation of water budgeting parameters under different rice (Oryza sativa L.) cultivation methods

Journal of Applied and Natural Science ◽

10.31018/jans.v9i3.1370 ◽

2017 ◽

Vol 9 (3) ◽

pp. 1373-1380

Author(s):

Sagar Dattatraya Vibhute ◽

A. Sarangi ◽

D. K. Singh ◽

K. K. Bandhyopadhyay ◽

S. S. Parihar ◽

...

Keyword(s):

Oryza Sativa ◽

Water Balance ◽

Soil Water ◽

Water Loss ◽

Root Zone ◽

Agricultural Research ◽

Oryza Sativa L ◽

Soil Water Balance ◽

Total Water ◽

Cultivation Methods

Water budgeting studies under different rice cultivation methods provides an insight into the amount of water used by the plant and percolated below the root zone for judicious water management. To undertake this study, a field experiment was conducted to estimate different soil water balance parameters under three rice (Oryza sativa L.) cultivation methods viz. Direct Seeded Rice (DSR), System of Rice Intensification (SRI) and Conventional Puddled Rice (CPR). The experiment was conducted during kharif 2013 and kharif 2014 season at research farm of Indian Council of Agricultural Research-Indian Agricultural Research Institute, New Delhi, India. In this study, the rainfall and irrigation depth, Crop Evapotranspiration (ETc), percolation beyond root zone of the crop and surface runoff during the crop growth period were accounted in water budgeting. It was observed that the percolation be-yond root zone of the crop was the highest under CPR method amounting 963 mm and 831 mm, which was about 55% and 58% of total water applied during 2013 and 2014, respectively. However, the percolation beyond root zone of the crop was the lowest under DSR method of rice cultivation amounting 367 mm and 332 mm which was 43% and 39% of total water applied during 2013 and 2014, respectively. Water loss through Etc was around 30% of total water applied in all three cultivation methods for year 2013. However, it was 59%, 46% and 43% of total water ap-plied for DSR, SRI and CPR, respectively in the year 2014.This indicates more effective utilization of total applied water in the year 2014.The study highlighted that water loss through deep percolation beyond root zone is the major factor contributing to the high water requirement in CPR and SRI methods compare to DSR method. Moreover, different soil water balance components computed in this study will be helpful for estimation of irrigation water requirement in the rice growing areas of the agro-climatic region VI (Trans-gangetic Plains) of India.

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