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 Determination of soil water tension for irrigation management of sweet sorghum

2016 ◽  
Vol 37 (3) ◽  
pp. 1189
Author(s):  
Karen Marcelle de Jesus Silva ◽  
Ignacio Aspiazú ◽  
Arley Fiqueiredo Portugal ◽  
Renato Mendes de Oliveira ◽  
Polyanna Mara de Oliveira ◽  
...  
Keyword(s):  
Soil Water ◽  
Sweet Sorghum ◽  
Block Design ◽  
Irrigation Management ◽  
Soluble Solids ◽  
Water Retention Curve ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Water Tension ◽  
Water Tension

Culturing of sweet sorghum is being considered as an excellent option for ethanol production, from an agronomical and industrial point of view. At present, information regarding the best soil water tension for beginning sweet sorghum irrigation is not available; hence, this study aimed to determine the adequate soil water tension under field conditions for beginning irrigation of four cultivars of sorghum. Two experiments were conducted at Nova Porteirinha, MG, in a randomized block design with sub-subdivided plots having four replications. Each experiment comprised six treatments of soil water tension (plots)-20, 40, 60, 80, 100, and 120 kPa-for resuming sweet sorghum irrigation, and four sweet sorghum cultivars (subplots)-BRS 508, BRS 509, BRS 511, and CMSXS647. After planting, the soil water level in the plots was elevated to field capacity (10 kPa), and then the treatments were applied. During treatment application, irrigation was resumed when the soil water tension reached the limit established in order to elevate the soil water tension to 10 kPa. The amount of water replaced during each irrigation was determined by generating a soil water retention curve for the experimental area. The following parameters were evaluated: green mass production, juice volume, soluble solids (Brix), and tons of Brix per hectare (TBH). The different soil water tensions and cultivars, agricultural year, and interaction between tension and year significantly affected (p ? 0.05) the characteristics evaluated, according to the F test. The agronomical characteristics of the evaluated cultivars showed linear relationship with water supply in the soil. According to TBH, irrigation of sweet sorghum needs to be performed when the soil tension reaches 20 kPa. The TBH values did not differ significantly among the four cultivars at the 5% significance level according to Tukey test.

scholarly journals TENSÃO DE ÁGUA NO SOLO PARA O REINÍCIO DA IRRIGAÇÃO DE MILHO VERDE NO SEMIÁRIDO

2018 ◽  
Vol 17 (2) ◽  
pp. 190
Author(s):  
IGNACIO ASPIAZÚ ◽  
FERNANDO GOMES DA SILVA ◽  
RENATO MENDES OLIVEIRA ◽  
KAREN MARCELLE DE JESUS SILVA ◽  
SILVÂNIO RODRIGUES DOS SANTOS ◽  
...  
Keyword(s):  
Zea Mays ◽  
Soil Water ◽  
Zea Mays L ◽  
Irrigation Management ◽  
Winter Season ◽  
Dry Mass ◽  
Area Index ◽  
Soil Water Tension ◽  
Yield Parameters ◽  
Water Tension

  RESUMO O objetivo deste trabalho foi determinar em campo a tensão de água do solo adequada para o reinício da irrigação do milho verde no semiárido. O experimento constou de seis valores de tensão matricial da água do solo (20 kPa, 40 kPa, 60 kPa, 80 kPa, 100 kPa e 120 kPa) testadas em uma cultivar de milho, o hibrido duplo AG 1051. O experimento foi instalado no período de inverno de 2013, nos meses de agosto a novembro, num delineamento experimental de blocos casualizados (DBC), com quatro repetições, conduzidos na fazenda experimental da Embrapa Milho e Sorgo em Nova Porteirinha, MG. Foram avaliadas as variáveis: produtividade de espigas sem palha (t ha-1), número de espigas totais e comerciais por hectare, comprimento de espigas com palha e sem palha e diâmetro de espigas comerciais. Dentre os resultados pode-se constatar que os maiores valores para as variáveis de morfologia e de produtividade foram obtidos quando a irrigação foi efetuada com tensão próxima de 50 kPa, tornando-a a tensão mais adequada para o uso racional da água no manejo da irrigação do milho verde.Palavras-chave: Zea mays L., déficit hídrico, manejo da irrigação, resistência elétrica. SOIL WATER TENSION FOR REWATERING GREEN CORN IN THE SEMIARID  ABSTRACT _ The objective of this work was to determine the adequate water tension for rewatering green corn at field conditions in the semiarid. The experiment consisted of six values of matric soil water tension (20 kPa, 40 kPa, 60 kPa, 80 kPa, 100 kPa and 120 kPa) and one maize cultivar, the double hybrid AG1051. The experiment was installed in the 2013 winter season, from August to November, in a randomized blocks design (DBC), with four replicates, and conducted at the experimental farm belonging to Embrapa Maize and Sorghum in Nova Porteirinha, MG. Morphological parameters were evaluated such as plant height, leaf area index and dry mass, and also the yield parameters such as weight of spikes with straw and without straw (t ha-1), number of total and commercial spikes per hectare, diameter of commercial spikes and length of commercial spikes with and without straw. The highest values for the morphology and productivity variables were obtained when irrigation was carried out with a tension close to 50 kPa, which proved to be the most suitable tension for the rational use of water in the irrigation management of green corn.Keywords: Zea mays L., water deficit, irrigation management, electrical resistance.

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 VIABILIDADE PRODUTIVA DA CULTURA DA BATATA SUBMETIDA A DIFERENTES TENSÕES DE AGUA NO SOLO

Irriga ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 306
Author(s):  
Luciano Oliveira Geisenhoff ◽  
Geraldo Magela Pereira ◽  
Joaquim Alves Lima Junior ◽  
Rodrigo Otavio Rodrigues de Melo Souza ◽  
Ana Carla Ferreira Oliveira
Keyword(s):  
Solanum Tuberosum ◽  
Soil Water ◽  
Solanum Tuberosum L ◽  
Irrigation Management ◽  
Economic Feasibility ◽  
Dry Matter Content ◽  
Trickle Irrigation ◽  
Fresh Weight ◽  
Soil Water Tension ◽  
Water Tension

VIABILIDADE PRODUTIVA DA CULTURA DA BATATA SUBMETIDA A DIFERENTES TENSÕES DE AGUA NO SOLO LUCIANO OLIVEIRA GEISENHOFF1; GERALDO MAGELA PEREIRA2; JOAQUIM ALVES DE LIMA JUNIOR3; RODRIGO OTAVIO RODRIGUES DE MELO SOUZA4 E ANA CARLA FERREIRA DE OLIVEIRA5  1Engº Agrônomo, Prof. Doutor, Faculdade de Ciências Agrárias - FCA/Universidade Federal da Grande Dourados - UFGD/ Dourados – MS, Fone: (67) 3410-2412, [email protected] 2Engº Agrícola, Prof. Doutor, Departamento de Engenharia Agrícola-DEG/Universidade Federal de Lavras - UFLA/Lavras – MG, Fone: (35) 38291389, [email protected]º Agrônomo, Prof. Doutor, Universidade Federal Rural da Amazônia - UFRA/Campus Capanema – PA, Fone: (91) 98160-6563, [email protected]º Agrícola, Prof. Doutor, Universidade Federal Rural da Amazônia - UFRA/Campus Belém – PA, Fone: (91) 98193-0182, [email protected]º Agrônoma, Mestranda em Agronomia, Universidade Federal Rural da Amazônia - UFRA/Campus Belém – PA, Fone: (91) 98171-1538, [email protected]  1 RESUMO A irrigação da batata (Solanum tuberosum L.), como na maioria das olerícolas, além de ser um importante fator de produção, é o que mais favorece o aumento da produtividade, bem como, o aprimoramento da qualidade do produto. Desta forma, objetivou-se com o presente estudo avaliar a resposta da cultura da batata, cultivar Ágata, a diferentes tensões de água no solo, irrigada por gotejamento, visando estabelecer critérios para o manejo da irrigação na cultura da batata. O experimento foi conduzido em campo, em área experimental do Departamento de Engenharia da Universidade Federal de Lavras (UFLA), no período de julho a outubro de 2010. O delineamento experimental utilizado foi em blocos casualizados (DBC), compreendendo-se cinco tratamentos e quatro repetições. Os tratamentos constituíram-se de cinco tensões da água no solo, 15, 35, 55, 75 e 95 kPa. Para a obtenção dos maiores valores de: massa fresca total de tubérculos por planta, massa fresca média de tubérculos por planta, produtividade total de tubérculos, massa fresca de tubérculos comerciais por planta, produtividade de tubérculos comerciais, número de tubérculos comerciais por planta, associados a uma excelente classificação comercial, as irrigações devem ser realizadas quando a tensão de água no solo acusar o valor de 15 kPa, á uma profundidade de 0,15 m. O rendimento produtivo da cultura reduziu em função do aumento da tensão da água no solo, no intervalo entre 15 e 95 kPa. O teor de matéria seca de tubérculos apresentou resposta aos tratamentos, sendo que o valor máximo de 18,77% foi obtido com a tensão de 60 kPa.  Palavras-chaves: Solanum tuberosum L., Irrigação localizada, Manejo da irrigação.  GEISENHOFF, L. O.; PEREIRA, G. M.; LIMA JUNIOR, J. A.; SOUZA, R. O. R. M.; OLIVEIRA, A. C. F.VIABILITY PRODUCTION OF POTATO CROP UNDER SUBMITTED TO DIFFERENT SOIL WATER TENSION  2 ABSTRACT  The irrigation of potato ( Solanum tuberosum L.) , as in most vegetable crops, as well as being an important factor of production, is what most favors the increase of productivity as well as the improvement of product quality. Thus, objective with this study evaluate the response of the potato cultivar Agate, different strains of soil water, trickle irrigated, in order to establish criteria for irrigation management, as well estimating the economic feasibility of irrigation system in potato.The experiment was conducted in an open field in the experimental area of Department of Engineering, Federal University of Lavras (UFLA), during july-october 2010.The experimental design was randomized blocks (DBC), comprising up five treatments and four replicates.The treatments consisted of five soil water stress, 15, 35, 55, 75 and 95 kPa. It was concluded that to obtain higher values: total fresh weight of tubers per plant, mean fresh weight of tubers per plant, total yield of tubers, fresh weight of marketable tubers per plant, yield of marketable tubers, number of marketable tubers per plant, associated with an excellent commercial grading, irrigation should be done when the soil water tension acknowledge the value of 15 kPa at a depth of 0.15 m. The yield of crop yield declined linearly with increasing soil water tension in the range between 15 and 95 kPa. The dry matter content of tubers showed a quadratic response to treatments, and the maximum value of 18.77% was obtained with a tension of 60 kPa. Keywords: Solanum tuberosum L, Trickle irrigation, Irrigation management

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 CULTIVO DA BETERRABA SOB DIFERENTES TENSÕES DE ÁGUA NO SOLO

Irriga ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 220-235
Author(s):  
Jonathan Rocha Miranda ◽  
Geraldo Magela Pereira
Keyword(s):  
Soil Water ◽  
Water Use ◽  
Drip Irrigation ◽  
Irrigation Management ◽  
Innovative Design ◽  
Soil Water Tension ◽  
Experimental Area ◽  
Engineering Department ◽  
Water Tension

CULTIVO DA BETERRABA SOB DIFERENTES TENSÕES DE ÁGUA NO SOLO     JONATHAN DA ROCHA MIRANDA¹ E GERALDO MAGELA PEREIRA²   1Doutorando em Engenharia Agrícola pela Universidade Federal de Lavras (UFLA) – Campus Universitário, Departamento de Engenharia, C.P. 3037 – CEP 37200-000, Lavras-MG, Brasil. [email protected]; ²Professor Titular da Universidade Federal de Lavras (UFLA) - Campus Universitário, Departamento de Engenharia, C.P. 3037- CEP 37200-000, Lavras-MG, Brasil. [email protected].     1 RESUMO   Objetivou-se com este estudo, avaliar o efeito de diferentes tensões de água no solo sobre a produção de beterraba, cultivada em ambiente protegido e irrigada por gotejamento, de forma a estabelecer critérios para o manejo adequado da irrigação. O experimento foi conduzido na área experimental do Departamento de Engenharia da Universidade Federal de Lavras, no período de fevereiro a maio de 2016. O delineamento experimental utilizado foi em blocos completos casualizados, com seis tratamentos e quatro repetições. Os tratamentos corresponderam as tensões da água no solo de 15; 25; 35; 45; 55 e 65 kPa. Conclui-se que para a obtenção de maior produtividade e eficiência no usa da água, as irrigações devem ser realizadas quando a tensão da água no solo estiver em torno de 15 kPa, a uma profundidade de 0,15 m.   Palavras-chave: Manejo de irrigação; Ambiente protegido; Sensor de Resistência Elétrica; Eficiência no Uso da Água.     MIRANDA, J.R; PEREIRA, G.M. BEET CULTIVATION UNDER DIFFERENT SOIL WATER TENSIONS     2 ABSTRACT   The objective of this study was to evaluate the effect of different soil water stresses on beet production, cultivated in a protected environment and irrigated by drip irrigation, to establish criteria for proper irrigation management. The experiment was conducted in the experimental area of the Engineering Department of the Federal University of Lavras (UFLA), from February to May 2016. The innovative design was a randomized complete block (DBC), with six treatments and four replications. The treatments consisted of six soil water tension stresses (15, 25, 35, 45, 55 and 65 kPa). From the results obtained, it was concluded that to achieve higher values of productivity and efficiency in the use of water, irrigations should be carried out when the water tension in the soil is around 15 kPa, to a depth of 0.15 m.   Keywords: Irrigation management; Protected environment; Watermark, Efficiency in Water Use.

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 GERENCIAMENTO DA IRRIGAÇÃO DO FEIJOEIRO BASEADO EM CRITÉRIOS TÉCNICOS E ECONÔMICOS NO CERRADO

Irriga ◽  
2008 ◽  
Vol 13 (3) ◽  
pp. 378-391 ◽  
Author(s):  
Sebastião Francisco Figuerêdo ◽  
Eder João Pozzebon ◽  
José Antonio Frizzone ◽  
Juscelino Antonio de Azevedo ◽  
Antônio Fernando Guerra ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Experiments ◽  
Soil Depth ◽  
Irrigation Management ◽  
Maximum Yield ◽  
Field Capacity ◽  
Irrigated Agriculture ◽  
Economic Return ◽  
Soil Water Tension ◽  
Water Tension

Gerenciamento da irrigação do feijoeiro baseado em critérios técnicos e econômicos no Cerrado  Sebastião Francisco Figuerêdo1; Eder João Pozzebon2; José Antonio Frizzone3; Juscelino Antonio de Azevedo1; Antônio Fernando Guerra1;Euzébio Medrado da Silva11Embrapa Cerrados, Brasília, DF,  [email protected]ência Nacional de Águas (ANA), Brasília, DF3Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP  1 Resumo O conhecimento sobre o manejo da irrigação sob condições de escassez de água é essencial para o aperfeiçoamento da agricultura irrigada. Nesse sentido, este trabalho foi realizado objetivando definir níveis de tensão de água no solo, mais adequados para o início das irrigações do feijoeiro no Cerrado, baseado em critérios técnicos e econômicos. Foram conduzidos experimentos na Embrapa Cerrados-DF, durante três anos, em blocos ao acaso, testando, como tratamentos, as seguintes tensões: 33kPa, 50kPa, 70kPa, 100kPa, 500kPa e 1000kPa, na profundidade de 10cm. As irrigações foram aplicadas até a capacidade de campo, na camada de 0-40cm. No intervalo37 a967kPa, o rendimento de grãos reduziu-se, em forma logarítmica, com o aumento da tensão e, quadrática, com as lâminas totais. Os maiores rendimentos foram obtidos quando a irrigação era feita na tensão de água em torno de 37kPa. Entretanto, ao se considerar uma situação média estudada de custo da água e de preço do feijão, o nível de tensão mais adequado, para maior lucratividade, passou para 61kPa. As análises mostraram que baixos custos da água e altos preços do feijão levam aos pontos de máximo rendimento de grãos e de lucratividade a se aproximarem. Numa situação contrária, esses pontos se distanciam, resultando em economia de água.   UNITERMOS: Tensão da água no solo, análise econômica, manejo da irrigação, otimização da irrigação.  Figuerêdo, S. F.; Pozzebon, E.J.; Frizzone, J. A. ;  Azevedo, J. A. de; Guerra, A.F.;   Silva, E. M. da.  MANAGEMENT OF DRYBEAN IRRIGATION BASED ON TECHNICAL AND ECONOMICAL CRITERIA IN CERRADO  2 abstract The knowledge on irrigation management under deficit conditions is essential to improve irrigated agriculture. Thus, this work was developed in order to define the most adequate soil-water tensions to begin irrigating drybean crop in Cerrado, based on technical and economical criteria. Field experiments were conducted in Embrapa/Cerrados-DF,Brazil, during three years in a randomized block scheme using as treatments the following soil-water tensions: 33kPa, 50kPa, 100kPa, 500kPa and 1000kPa, ate a 10-cm depth. The irrigations were applied until field capacity filled the 40-cm soil depth. In the interval from 37 to 96kPa, grain yield decreased logarithmically with the increase of soil-water tension and, quadratically with total applied water. The highest yields were obtained when the irrigations were conducted with soil-water tension around 37kPa. However, after considering the water irrigation costs and the grain dry bean price, the best soil-water tension for getting larger economic return was 61kPa.The analysis showed that the combination of low irrigation costs and high grain drybean prices makes the breakeven points of total water applied for maximum yield and maximum economic return to similar. In an opposite situation, those costs are very different, resulting in larger water economy. Key words: Soil-water tension, economical analysis, irrigation management, optimizing irrigation.

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.

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