scholarly journals Effects of soil water depletion on the water relations in tropical kudzu

1999 ◽  
Vol 34 (7) ◽  
pp. 1151-1157
Author(s):  
Adaucto Bellarmino de Pereira-Netto ◽  
Antonio Celso Novaes de Magalhães ◽  
Hilton Silveira Pinto
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Content ◽  
Soil Water ◽  
Cover Crop ◽  
Soil Water Depletion ◽  
Pueraria Phaseoloides ◽  
Water Depletion ◽  
Relative Water ◽  
Dry Soil

Tropical kudzu (Pueraria phaseoloides (Roxb.) Benth., Leguminosae: Faboideae) is native to the humid Southeastern Asia. Tropical kudzu has potential as a cover crop in regions subjected to dryness. The objective of this paper was to evaluate the effect of soil water depletion on leaflet relative water content (RWC), stomatal conductance (g) and temperature (T L) in tropical kudzu. RWC of waterstressed plants dropped from 96 to 78%, following a reduction in SWC from 0.25 to 0.17 g (H2O).g (dry soil)-1.Stomatal conductance of stressed plants decreased from 221 to 98 mmol.m-2.s-1, following the reduction in soil water content (SWC). The day after re-irrigation, g of water stressed plants was 15% lower than g of unstressed plants. Differences in T L between waterstressed and unstressed plants (deltaT L) rose linearly from 0.1 to 2.2ºC following progressive water deficit. RWC and T L of waterstressed plants paralled RWC and T L of unstressed plants the day after reirrigation. The strong decrease in SWC found in this study only induced moderate water stress in tropical kudzu. In addition, tropical kudzu recover rapidly from the induced water stress after the re-irrigation.

scholarly journals Soil Structure and Texture Effects on the Precision of Soil Water Content Measurements with a Capacitance- Based Electromagnetic Sensor

2020 ◽  
Vol 63 (1) ◽  
pp. 141-152
Author(s):  
Jasreman Singh ◽  
Derek M. Heeren ◽  
Daran R. Rudnick ◽  
Wayne E. Woldt ◽  
Geng Bai ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Sensor Calibration ◽  
Soil Water Depletion ◽  
Undisturbed Soil ◽  
Water Depletion ◽  
Soil Moisture Sensors ◽  
Electromagnetic Sensor

HighlightsCapacitance-based electromagnetic soil moisture sensors were tested in disturbed and undisturbed soils.The uncertainty in estimation of soil water depth was lower using the undisturbed soil sample calibrations.The uncertainty in estimation of soil water depletion was lower than the uncertainty in volumetric water content.Undisturbed calibration of water depletion quantifies water demand with better precision and avoids over-watering.Abstract. The physical properties of soil, such as structure and texture, can affect the performance of an electromagnetic sensor in measuring soil water content. Historically, calibrations have been performed on repacked samples in the laboratory and on soils in the field, but little research has been done on laboratory calibrations with intact (undisturbed) soil cores. In this study, three replications each of disturbed and undisturbed soil samples were collected from two soil texture classes (Yutan silty clay loam and Fillmore silt loam) at a field site in eastern Nebraska to investigate the effects of soil structure and texture on the precision of a METER Group GS-1 capacitance-based sensor calibration. In addition, GS-1 sensors were installed in the field near the soil collection sites at three depths (0.15, 0.46, and 0.76 m). The soil moisture sensor had higher precision in the undisturbed laboratory setup, as the undisturbed calibration had a better correlation [slope closer to one, R2undisturbed (0.89) > R2disturbed (0.73)] than the disturbed calibrations for the Yutan and Fillmore texture classes, and the root mean square difference using the laboratory calibration (RMSDL) was higher for pooled disturbed samples (0.053 m3 m-3) in comparison to pooled undisturbed samples (0.023 m3 m-3). The uncertainty in determination of volumetric water content (?v) was higher using the factory calibration (RMSDF) in comparison to the laboratory calibration (RMSDL) for the different soil structures and texture classes. In general, the uncertainty in estimation of soil water depth was greater than the uncertainty in estimation of soil water depletion by the sensors installed in the field, and the uncertainties in estimation of depth and depletion were lower using the calibration developed from the undisturbed soil samples. The undisturbed calibration of soil water depletion would determine water demand with better precision and potentially avoid over-watering, offering relief from water shortages. Further investigation of sensor calibration techniques is required to enhance the applicability of soil moisture sensors for efficient irrigation management. Keywords: Calibration, Capacitance, Depletion, Irrigation, Precision, Sensor, Soil water content, Structure, Uncertainty.

scholarly journals Identifying Within-Field Spatial and Temporal Crop Water Stress to Conserve Irrigation Resources with Variable-Rate Irrigation

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1377
Author(s):  
Jeffrey D. Svedin ◽  
Ruth Kerry ◽  
Neil C. Hansen ◽  
Bryan G. Hopkins
Keyword(s):  
Electrical Conductivity ◽  
Water Stress ◽  
Soil Water ◽  
Variable Rate ◽  
Soil Electrical Conductivity ◽  
Soil Water Depletion ◽  
Crop Water ◽  
Water Depletion ◽  
Crop Water Stress ◽  
Variable Rate Irrigation

Addressing within-field and within-season variability of crop water stress is critical for spatially variable irrigation. This study measures interactions between spatially variable soil properties and temporally variable crop water dynamics; and whether modelling soil water depletion is an effective approach to guide variable-rate irrigation (VRI). Energy and water balance equations were used to model crop water stress at 85 locations within a 22 ha field of winter wheat (Triticum aestivum L.) under uniform and spatially variable irrigation. Significant within-field variability of soil water holding capacity (SWHC; 145–360 mm 1.2 m−1), soil electrical conductivity (0.22–49 mS m−1), spring soil water (314–471 mm 1.2 m−1), and the onset of crop water stress were observed. Topographic features and modelled onset of crop water stress were significant predictors of crop yield while soil moisture at spring green-up, elevation, and soil electrical conductivity were significant predictors of the onset of crop water stress. These results show that modelling soil water depletion can be an effective scheduling tool in VRI. Irrigation zones and scheduling efforts should consider expanding to include temporally dynamic factors, including spring soil water content and the onset of crop water stress.

Photosynthesis and Stomatal-Conductance Responses of Johnsongrass (Sorghum halepense) to Water Stress

Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 635-639 ◽  
Author(s):  
Bryan L. Stuart ◽  
Daniel R. Krieg ◽  
John R. Abernathy
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Osmotic Potential ◽  
Grain Filling ◽  
Leaf Temperature ◽  
Sorghum Halepense

The influence of water stress on johnsongrass [Sorghum halepense(L.) Pers. ♯ SORHA] physiology was evaluated in a semiarid environment. Stomatal conductance of johnsongrass responded to more negative leaf water potential and increasing leaf temperature. The sensitivity of the leaf temperature effect was dependent on the soil water content. At low soil water content, conductance was limited by low water potential, and increasing leaf temperature had little effect. Conductance of CO2was related to net photosynthesis in a curvilinear manner, with conductance levels greater than 0.3 mol·m-2· s-1being in excess of that necessary for maximum photosynthesis. At both high conductance levels and low levels associated with increased water stress, intercellular CO2concentration increased, indicating nonstomatal limitations to photosynthesis. Decreased osmotic potential provided the highest correlation with the linear decline of photosynthetic rate as stress intensified. The expression of osmotic adjustment in johnsongrass is reported during grain filling. Plants in the milkdough stage of grain filling had approximately 0.3 MPa lower osmotic potential at any relative water content than those at anthesis.

scholarly journals Physiological Response of Carambola Trees to Soil Water Depletion in Krome Soils

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 857B-857
Author(s):  
Rashid Al-Yahyai* ◽  
Bruce Schaffer ◽  
Frederick S. Davies
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Gas Exchange ◽  
Stem Water Potential ◽  
Soil Water Depletion ◽  
Water Depletion ◽  
Loam Soil ◽  
Stem Water

The effect of soil water depletion on plant water potential and leaf gas exchange of carambola (Averrhoa carambola L. cv. Arkin) in Krome very gravelly loam soil was studied in an orchard and in containers in the field and in a greenhouse. The rate of soil water depletion was determined by continuously monitoring soil water content with multi-sensor capacitance probes. Stem water potential and leaf gas exchange of carambola in containers were reduced when the soil water depletion level fell below 50% (where field capacity = 100%). Although there was a decrease in the rate of soil water depletion in the orchard as the soil dried, soil water depletion did not go below an average of 70%. This was presumably due to sufficient rainfall and capillary movement of water in the soil. Therefore, soil water content did not decline sufficiently to affect leaf gas exchange and leaf and stem water potential of orchard trees. A decline in soil water depletion below 40% resulted in a concomitant decline in stem water potential of the container trees in the field and greenhouse to below -1.0 MPa. Stomatal conductance, net CO2 assimilation, and transpiration declined significantly when stem water potential was below -1.0 MPa. The reduction of net CO2 assimilation and transpiration was proportional to the decline in stomatal conductance of container trees in the field and greenhouse. Thus, soil water depletion in Krome very gravelly loam soil must be less than 50% before water potential or leaf gas exchange of carambola is affected. Based on these results, irrigation scheduling should be based on physiological variables such as stem water potential and stomatal conductance or the amount rather than the rate of soil water depletion.

scholarly journals RESPOSTAS FISIOLÓGICAS E PRODUTIVAS DA PALMA DE ÓLEO IRRIGADA EM FASE INICIAL DE DESENVOLVIMENTO

Irriga ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 405-423 ◽  
Author(s):  
Jessica Lima Viana ◽  
Cornélio Alberto Zolin ◽  
Vanessa Quitete Ribeiro da Silva ◽  
Adilson Pacheco de Souza
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Soil Water ◽  
Water Deficit ◽  
Oil Palm ◽  
Irrigation Management ◽  
Fresh Mass ◽  
Soil Water Depletion ◽  
Mato Grosso ◽  
Water Depletion

RESPOSTAS FISIOLÓGICAS E PRODUTIVAS DA PALMA DE ÓLEO IRRIGADA EM FASE INICIAL DE DESENVOLVIMENTO     JESSICA LIMA VIANA1; CORNÉLIO ALBERTO ZOLIN2; VANESSA QUITETE RIBEIRO DA SILVA2 E ADILSON PACHECO DE SOUZA3   1 Programa de Pós-Graduação em Ciência do Solo, Universidade Federal do Paraná (UFPR), Rua dos Funcionários, 1540, Juvevê, CEP: 80035-050, Curitiba, Paraná, Brasil, [email protected]. 2 Pesquisador(a), Embrapa Agrossilvipastoril, Rodovia dos Pioneiros MT-222, Km 2,5, Zona Rural, Caixa Postal: 343, CEP: 78550-970, Sinop, Mato Grosso, Brasil, [email protected]; [email protected]. 3 Professor, Instituto de Ciências Agrárias e Ambientais, Universidade Federal de Mato Grosso (UFMT), Avenida Alexandre Ferronato, 1200, Cidade Jardim, CEP: 78550-728, Sinop, Mato Grosso, Brasil, [email protected].     1 RESUMO   Objetivou-se avaliar a taxa fotossintética, taxa de transpiração, condutância estomática e a eficiência do uso da água e a produtividade (número e massa fresca dos cachos por planta) de duas cultivares de palma de óleo irrigada, com 4 anos e 4 meses de idade, em Sinop-MT. O delineamento experimental adotado foi de blocos casualizados, sendo os tratamentos às disponibilidades de água no solo de 80%, 60%, 40%, 20% e 0% em parcelas subdivididas nas cultivares BRS C2501 e BRS C2528, com três repetições.  A palma de óleo foi sensível ao déficit hídrico apresentando alterações nas variáveis fisiológicas e redução no número e massa fresca dos cachos. A máxima taxa fotossintética da palma de óleo (A = 23,32 µmol m-2 s-1) foi obtida com 80% da disponibilidade de água no solo, independentemente da cultivar. As palmas de óleo sem irrigação submetidas a deficiência hídrica recuperam a taxa de fotossíntese, transpiração e condutância estomática no período chuvoso, indicando tolerância à deficiência hídrica e eficiência na regulação estomática.   Palavras-chave: déficit de pressão de vapor, Elaeais guineenses, manejo da irrigação, trocas gasosas.     VIANA, J. L.; ZOLIN, C. A.; SILVA, V. Q. R. da; SOUZA, A. P. de PHYSIOLOGICAL AND PRODUCTIVE RESPONSES OF IRRIGATED OIL PALM IN EARLY DEVELOPMENT PHASE     2 ABSTRACT   The aim of this study is to assess gas exchange (photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency) and yield characteristics (number and fresh mass of bunches) of oil palm under soil water depletion levels. This study was carried out in the experimental field of Embrapa Agrossilvi pastoril, in the north region of the state of Mato Grosso. The experimental design was randomized blocks in subdivided plots. Main plots consisted of five soil water depletion levels, respectively 80%, 60%, 40%, 20% and 0%. Subplots were represented by two cultivars (BRS C2501 and BRS C2528) with three replications. The oil palm was sensitive to water deficit presenting physiological changes and reduction in number and fresh mass of bunches. The maximum photosynthetic rate of oil palms was obtained with 80% of soil water depletion level (A = 23.32 μmol m-2 s-1), regardless of the cultivars. Plants under strong water deficit (without irrigation) recovered the rate of photosynthesis, transpiration and stomatal conductance in the rainy season, indicating tolerance to water deficit and efficiency in stomatal regulation.   Keywords: vapor pressure deficit, Elaeais guineenses, irrigation management, gas exchange.

scholarly journals Cover Crop Management on the Southern High Plains: Impacts on Crop Productivity and Soil Water Depletion

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 212
Author(s):  
Lisa L. Baxter ◽  
Charles P. West ◽  
C. Philip Brown ◽  
Paul E. Green
Keyword(s):  
Soil Water ◽  
Cover Crops ◽  
Cover Crop ◽  
The United States ◽  
Eragrostis Tef ◽  
High Plains ◽  
Soil Water Depletion ◽  
Southern High Plains ◽  
Water Depletion ◽  
No Till

The imminent depletion of the Ogallala Aquifer demands innovative cropping alternatives. Even though the benefits of cover crops are well recognized, adoption has been slow in the Southern High Plains (SHP) of the United States because of concerns that cover crops withdraw soil water to the detriment of the summer crops. This small plot experiment tested the interacting effects—production, soil water depletion of the cover crops, and subsequent teff [Eragrostis tef (Zucc.) Trotter] summer hay crops—of irrigation and tillage management with five cover crop types to identify low-risk cover crop practices in the drought-prone SHP. Dryland rye (Secale cereale L.) produced modest forage biomass (>1000 kg ha−1), even in a dry year, but it was found that light irrigation should be used to ensure adequate forage supply (>1200 kg ha−1) if winter grazing is desired. No-till management and timely termination of the winter cover crops were crucial to reducing the negative impact of winter crops on summer teff production. The results indicated no detriment to soil water content that was attributable to planting no-till cover crops compared with the conventional practice of winter fallow. Therefore, producers could take advantage of the soil-conserving attributes of high-quality winter forage cover crops without experiencing significant soil water depletion.

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