scholarly journals Soil Water Tension, a Powerful Measurement for Productivity and Stewardship

HortScience ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Clinton C. Shock ◽  
Feng-Xin Wang
Keyword(s):  
Soil Water ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Plant Performance ◽  
Vegetable Crops ◽  
Crop Species ◽  
High Productivity ◽  
Soil Water Tension ◽  
Water Tension

A fundamental way to schedule irrigation is through the monitoring and management of soil water tension (SWT). Soil water tension is the force necessary for plant roots to extract water from the soil. With the invention of tensiometers, SWT measurements have been used to schedule irrigation. There are different types of field instruments used to measure SWT, either directly or indirectly. Precise irrigation scheduling by SWT criteria is a powerful method to optimize plant performance. Specific SWT criteria for irrigation scheduling have been developed to optimize the production and quality of vegetable crops, field crops, trees, shrubs, and nursery crops. This review discusses known SWT criteria for irrigation scheduling that vary from 2 to 800 kPa depending on the crop species, plant product to be optimized, environmental conditions, and irrigation system. By using the ideal SWT and adjusting irrigation duration and amount, it is possible to simultaneously achieve high productivity and meet environmental stewardship goals for water use and reduced leaching.

scholarly journals An Irrigation Scheduling Model for Turnip Greens

1993 ◽  
Vol 118 (6) ◽  
pp. 726-730 ◽  
Author(s):  
Eric H. Simonne ◽  
Doyle A. Smittle ◽  
Harry A. Mills
Keyword(s):  
Irrigation System ◽  
Irrigation Scheduling ◽  
Leafy Vegetables ◽  
Pan Evaporation ◽  
Class A ◽  
Soil Water Tension ◽  
Scheduling Model ◽  
Leaf Yield ◽  
Scheduling Irrigation ◽  
Water Tension

An irrigation scheduling model for turnip (Brassica rapa L.) was validated using a line-source irrigation system in a 2-year field trial. The model used a water balance, a variable root length, and a crop factor function of plant age (i). Evapotranspiration was computed daily as class A pan evaporation times a crop factor [CF(i) = 0.365 + 0.0154i-0.00011i2]. Irrigation according to the model maintained soil water tension at <25 kPa at a 30-cm depth. When rainfall amounts were less than water use, leaf yields responded quadratically to irrigation rates, from 0% to 160% of the model rate, and the highest leaf yield with the lowest water applications corresponded to the model rate. Therefore, this model could replace the “feel or see” methods commonly used for scheduling irrigation of leafy vegetables grown in the southeastern United States.

scholarly journals Irrigation management of muskmelon with tensiometry

2017 ◽  
Vol 9 (3) ◽  
Author(s):  
Márcio José de Santana ◽  
Guilherme de Almeida Bocate ◽  
Murilo Augusto Sgobi ◽  
Stefany Silva de Souza ◽  
Taynara Tuany Borges Valeriano
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Irrigation System ◽  
Irrigation Management ◽  
Fruit Weight ◽  
Fruit Yield ◽  
Stem Diameter ◽  
Soil Water Tension ◽  
Production And Consumption ◽  
Water Tension

The production and consumption of muskmelon have been increasing (MELO et al., 2014), thus, information on techniques for higher field productions are necessary. The experiment described in the present work was conducted in the IFTM, Uberaba, State of Minas Gerais, Brazil, aiming to evaluate the muskmelon yield under different soil water tensions. A randomized block experimental design was used with five treatments (soil water tensions of 10, 20, 30, 40 and 50 kPa) and four replications (plots of two rows of 14 plants). Two harvests were carried out and the fruit yield, stem diameter, number of fruits per plant and efficiency of water use were evaluated. Irrigation was performed with a drip irrigation system and managed with tensiometry. The cultivar Bonus n.2 was used with spacing of 1.0 x 0.6 m. The data of the variables were subjected to the F test and regression test. The treatments showed statistical differences in number of fruits per plant, fruit weight (fruit yield) and stem diameter. The highest fruit yield found was 1.36 kg fruit-1 and the highest water use efficiency was 4.08 g mm-1 with irrigation for a soil water tension of 10 kPa. The lowest fruit yield was found with irrigation for a soil water tension of 50 kPa.

scholarly journals Irrigation controller mechanically actuated by soil-water tension: II - Field evaluations

2017 ◽  
Vol 21 (5) ◽  
pp. 298-303
Author(s):  
Alexsandro C. S. Almeida ◽  
Tarlei A. Botrel ◽  
Steven R. Raine ◽  
Antonio P. de Camargo ◽  
Marinaldo F. Pinto ◽  
...  
Keyword(s):  
Soil Water ◽  
High Frequency ◽  
Root Zone ◽  
Irrigation System ◽  
Soil Surface ◽  
Field Evaluation ◽  
Water Source ◽  
Soil Water Tension ◽  
Water Tension ◽  
Hydraulic Valve

ABSTRACT In this study, a field evaluation of the performance of an irrigation controller mechanically actuated by soil-water tension (SWT) was performed. The controller employs a tensiometer used as a sensor of SWT to directly control a mechanically actuated hydraulic valve. Six controllers were installed in an orchard to control the irrigation for six rows of plants over 64 days. Each controller controlled the irrigation of one lateral drip line. The drip irrigation system was gravity-fed from a water source placed 7 m above the soil surface. The SWT and the pressure in each lateral line were measured to evaluate the performance of the controllers. All the controllers tested in the field autonomously initiated and terminated the irrigation during the evaluation. Irrigation events were initiated when values close to the set soil-tension values were reached and were terminated at lower soil-tension values. As the SWT in the root zone was maintained close to the setup threshold plus 20% tolerance for at least 90% of the evaluation period, the performance of the controllers was considered satisfactory. The proposed controller was shown to be functional and was operated effectively for an SWT range of up to 30 kPa, which is commonly encountered under high-frequency irrigation conditions.

scholarly journals Gaseous irrigation control system: descriptions and phisical tests for performance assessment

Bragantia ◽  
2006 ◽  
Vol 65 (3) ◽  
pp. 501-510 ◽  
Author(s):  
Adonai Gimenez Calbo ◽  
Washington Luiz de Carvalho e Silva
Keyword(s):  
Soil Water ◽  
Irrigation Management ◽  
Irrigation Scheduling ◽  
Measuring System ◽  
Measuring Device ◽  
Soil Water Tension ◽  
First Case ◽  
Immersion Technique ◽  
Irrigation Control ◽  
Water Tension

Irrigas is a water tension measuring system made out of a porous cup (sensor), connected to a gas pressurizing/measuring device by a flexible tube. Water tension (T) is obtained from the equation T=Td-p or T=Ts-p, where Td is the sensor desorption critical water tension (bubbling beginning), Ts is the sensor sorption critical water tension (bubbling ceasing) and p is the applied gas pressure. Differently from conventional tensiometers, the irrigas porous cup cavity is filled with air. This characteristics makes the irrigas system nearly maintenance free and also eliminates the need of making hydrostatic pressure corrections for sensor depth. The system was tested both in the desorption and sorption modes. In the first case the Richards pressure chamber was used to adjus)t the soil water tension which makes the porous cup air permeable. The water tension thus obtained was always practically equal to the Td values measured by the bubbling method, observation that is a physical validation of the barrel immersion technique for irrigas usage for irrigation management. Important for instrument dimensioning, porous cup water loss as a function of water tension measured from zero to Td was diminutive, increased with the soil water tension and was smaller in higher Td porous cups. In the sorption mode, functioning as a gaseous tensiometer, driven by a steady air-flow source, irrigas sensors yielded, directly, water tension readings ranging from zero to Ts. For irrigation scheduling purposes, commercial irrigas water tension systems can be selected according to crop critical water tension requirements.

scholarly journals Within-Field Variability in Granular Matrix Sensor Data and its Implications for Irrigation Scheduling

2020 ◽  
Vol 36 (4) ◽  
pp. 437-449
Author(s):  
Tsz Him Lo ◽  
H C Pringle ◽  
Daran R Rudnick ◽  
Geng Bai ◽  
L Jason Krutz ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Soil Water ◽  
Irrigation Scheduling ◽  
Sensor Data ◽  
Moisture Sensor ◽  
Soil Moisture Sensor ◽  
Soil Water Tension ◽  
Granular Matrix ◽  
Water Tension ◽  
Field Variability

Highlights Within-field variability was larger for individual depths than for the profile average across multiple depths. Distributions of the profile average were approximately normal, with increasing variances as the soil was drying. Probability theory was applied to quantify the effect of sensor set number on irrigation scheduling. The benefit of additional sensors sets may decrease for longer irrigation cycles and for more heterogeneous fields. Abstract. Even when located within the same field, multiple units of the same soil moisture sensor rarely report identical values. Such within-field variability in soil moisture sensor data is caused by natural and manmade spatial heterogeneity and by inconsistencies in sensor construction and installation. To better describe this variability, daily soil water tension values from 14 to 23 sets of granular matrix sensors during the middle part of four soybean site-years in the Mississippi Delta were analyzed. The soil water tension data were found to follow approximately normal distributions, to exhibit moderately high temporal rank stability, and to show strong positive correlation between mean and variance. Based on these observations and the existing literature, a probabilistic conceptual framework was proposed for interpreting within-field variability in granular matrix sensor data. This framework was then applied to investigate the impact of sensor set number (i.e., number of replicates) and irrigation triggering threshold on the scheduling of single-day and multi-day irrigation cycles. If a producer’s primary goal of irrigation scheduling is to keep soil water adequate in a particular fraction of land on average, the potential benefit from increasing sensor set number may be smaller than traditionally expected. Improvement, expansion, and validation of this probabilistic framework are welcomed for developing a practical and robust approach to selecting the sensor set number and the irrigation triggering threshold for diverse soil moisture sensor types in diverse contexts. Keywords: Irrigation scheduling, Probability, Sensors, Soil moisture, Soil water tension, Variability, Watermark.

scholarly journals Water Budgets to Schedule Irrigation for Vegetables

1992 ◽  
Vol 2 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Doyle A. Smittle ◽  
W. Lamar Dickens
Keyword(s):  
Water Use ◽  
Soil Depth ◽  
Irrigation System ◽  
Irrigation Scheduling ◽  
Pan Evaporation ◽  
Model Soil ◽  
Soil Water Tension ◽  
Summer Squash ◽  
Daily Water ◽  
Water Tension

Instrumented rainfall- and groundwater-protected irrigation shelters were used to establish relationships (daily crop factors) between pan evaporation and daily water use for several vegetables. Use of these daily crop factors (water use/pan evaporation) and pan evaporation data for scheduling irrigations are described. Snap bean (Phaseolus vulgaris L.) is used to illustrate irrigation scheduling by this method. A table of the model output with columnar headings of age, root depth, date, pan evaporation, crop factor, daily water use, cumulative water use, allowable water use, rainfall, and irrigation is presented. When irrigation was applied according to the model, soil water tension was held below 25 db at 6-inch (15-cm) soil depth. With varying irrigation rates under a line-source irrigation system, marketable pod yields were maximized at 100% of the model rate. Marketable yields of summer squash also were maximized when irrigation was applied at 100% of the model rate. Marketable yields of sweetpotato were not affected by irrigation rates ranging from 1% to 177% of the model rate.

Citrus Carbohydrate Levels were Related to Irrigation Frequency but Not Arbuscular Mycorrhizal Fungal (AMF) Inoculum

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498a-498
Author(s):  
Matthew W. Fidelibus ◽  
Chris A. Martin
Keyword(s):  
Soil Water ◽  
Arbuscular Mycorrhizal ◽  
Irrigation Frequency ◽  
Soil Water Tension ◽  
Root Starch ◽  
Carbohydrate Levels ◽  
Amf Communities ◽  
Sugar Levels ◽  
Shoot Mass ◽  
Water Tension

Sugar and starch concentrations in leaves and roots of Citrus volkameriana Tan and Pasq were measured in response to irrigation frequency and AMF inoculum. Non-mycorrhizal seedlings were treated with a soil inoculum from one of five different communities of AMF; two AMF communities from Arizona citrus orchard soils, and three communities from undisturbed desert soils. Plants were assigned to frequent (soil water tension > –0.01 MPa) or infrequent (soil water tension > –0.06 MPa) irrigation cycles and were container-grown in a glasshouse for 4 months before tissues were analyzed. Fungal inoculum source did not affect shoot or root carbohydrate levels. Plants grown under high irrigation frequency had increased leaf and root starch levels and increased root sugar levels compared with those under low irrigation frequencies. High irrigation frequency also increased shoot mass.

scholarly journals Effects of Irrigation Regimes on Yield and Water Use by Sweetpotato

1990 ◽  
Vol 115 (5) ◽  
pp. 712-714 ◽  
Author(s):  
Doyle A. Smittle ◽  
Melvin R. Hall ◽  
James R. Stansell
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Use ◽  
Ipomoea Batatas ◽  
Regression Equations ◽  
Marketable Yield ◽  
Water Regimes ◽  
Soil Water Tension ◽  
Water Tension ◽  
Storage Root Development

Sweetpotatoes [Ipomoea batatas (L.) Lam cv. Georgia Jet] were grown on two soil types in drainage lysimeters under controlled soil water regimes during 1982 and 1983. Water regimes consisted of irrigating the sweetpotatoes throughout growth when soil water tension at 23 cm exceeded 25, 50, or 100 kPa or by allowing a 100-kPa water stress before root enlargement, during early root enlargement, or throughout root enlargement. Water use and marketable yields were greater when sweetpotatoes were grown on a Tifton loamy sand (fine loamy, siliceous, thermic, Plinthitic Paleudult) than when grown on a Bonifay sand (loamy, siliceous, thermic, Grossarenic, Plinthitic Paleudult). Water use, marketable yield, and yield of U.S. #1 grade roots generally decreased when soil water tensions exceeded 25 kPa before irrigation, although soil water stress of 100 kPa during storage root development did not significantly affect yield. Regression equations are provided to describe the relationships of water use to plant age and to compute daily evapotranspiration: pan evaporation ratios (crop factors) for sweetpotatoes irrigated at 25, 50, and 100 kPa of soil water tension.

scholarly journals BROMATOLOGIA DE GRAMÍNEAS TROPICAIS SOB DIFERENTES TENSÕES DE ÁGUA NO SOLO EM AMBIENTE PROTEGIDO

Nativa ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 415
Author(s):  
Morgana Scaramussa Gonçalves ◽  
Wilian Rodrigues Ribeiro ◽  
Edvaldo Fialho Dos Reis ◽  
Antônio Carlos Cóser
Keyword(s):  
Soil Water ◽  
Crude Protein ◽  
Nutritive Value ◽  
Production Systems ◽  
Pasture Production ◽  
Tropical Grasses ◽  
Soil Water Tension ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Water Tension

A irrigação é usada para conter os efeitos da sazonalidade de produção garantindo maior intensificação dos sistemas de produção a pasto, assim, contribuindo para o aumento da produção e do valor bromatológico das gramíneas. Dessa forma, objetivou-se com esse trabalho avaliar o valor bromatológico de gramíneas tropicais cultivadas em condições de ambiente protegido, submetidas a diferentes tensões de água no solo. Foram realizados três experimentos com as gramíneas Mombaça, Marandu e Tifton 85, onde cada qual, foi conduzida em um esquema de parcelas subdivididas, tendo nas parcelas os níveis do fator tensão de água no solo (20, 40, 50, 60 e 70 kPa) e nas subparcelas níveis 1º, 2º e 3º do fator corte, em um delineamento inteiramente casualizado com cinco repetições. Nas tensões de água no solo de 20 (Mombaça) e 50 kPa (Marandu e Tifton 85) as gramíneas expressaram seu máximo de valor nutritivo. Os maiores teores de PB foram obtidos nas gramíneas Mombaça e Tifton 85. Para as variáveis FDN e FDA o fator tensão de água no solo não foi significativo.Palavras-chave: proteína bruta, fibra, irrigação, forrageiras. BROMATOLOGY OF TROPICAL GRASSES UNDER DIFFERENT SOIL WATER TENSIONS IN PROTECTED ENVIRONMENT ABSTRACT:The irrigation is used to contain the effects of seasonality of production, ensuring a greater intensification of pasture production systems, thus contributing to the increase of production and the bromatological value of grasses. Thus, the objective of this work was to evaluate the nutritive value of tropical grasses grown under protected environment conditions, subject to different soil water stresses. Three experiments, using Mombasa, Marandu and Tifton 85 grasses under a protected environment were carried out and each one was conducted in a subdivided plots scheme, with the levels of soil water tension factor (20, 40, 50, 60 and 70 kPa) and in the subplots levels 1, 2 and 3 of the cut factor, in a completely randomized design with five replicationss. At soil water stresses of 20 (Mombasa) and 50 kPa (Marandu and Tifton 85) the grasses expressed their maximum nutritive value. The highest CP levels were obtained in the Mombasa and Tifton 85 grasses. For the NDF and ADF variables, the soil water stress factor was not significant.Keywords: crude protein, fiber, irrigation, forages.

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