scholarly journals Improved Irrigation Management of Sweet Orange with Huanglongbing

HortScience ◽  
2017 ◽  
Vol 52 (6) ◽  
pp. 916-921 ◽  
Author(s):  
Said A. Hamido ◽  
Kelly T. Morgan ◽  
Robert C. Ebel ◽  
Davie M. Kadyampakeni
Keyword(s):  
Soil Water ◽  
Leaf Area ◽  
Sweet Orange ◽  
Irrigation Management ◽  
Irrigation Treatment ◽  
Irrigation Scheduling ◽  
Water Dynamics ◽  
Stem Water Potential ◽  
Area Index ◽  
The Impact

Because of the decline in production and negative economic effects, there is an urgent need for strategies to reduce the impact of Huanglongbing (HLB) on citrus [Citrus ×sinensis (L.) Osbeck]. The objective of this study was to evaluate the impact of different irrigation schedules on total available soil water (TAW) and water uptake characteristics of citrus trees affected by HLB in central and southwest Florida. The study was initiated in Jan. 2014 for 2 years on 5-year-old sweet orange trees located in three commercial groves at Arcadia, Avon Park, and Immokalee, FL. Each grove had three irrigation scheduling treatments including the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS) recommendations, Daily irrigation, and an Intermediate treatment. All groves received similar volumes of water per week based on evapotranspiration (ETo) reported by the Florida Automated Weather Network. Sap flow (SF) measurements were taken for two trees per treatment for at least 10 days per site (twice/year). During those periods, leaf area, leaf area index (LAI), and stem water potential (Ψ) were determined. Also, TAW was determined using drainage curve and capacitance soil moisture sensors installed at incremental soil depths of 0–15, 15–30, and 30–45 cm. Results showed significant differences in average SF, LAI, Ψ, and TAW measurements among treatments. Diurnal SF value under daily irrigation treatment increased by 91%, 51%, and 105% compared with UF/IFAS irrigation in Arcadia, Avon Park, and Immokalee, respectively. Soil water contents (WCs) under daily treatment increased by 59%, 59%, and 70% compared with UF/IFAS irrigation treatment in Arcadia, Avon Park, and Immokalee, respectively. Our results indicated that daily irrigation improved tree water dynamics compared with IFAS or Intermediate irrigation scheduling treatments and reduced tree stress with the same volume of water.

scholarly journals Water and Soil Nutrient Dynamics of Huanglongbing-Affected Citrus Trees as Impacted by Ground-Applied Nutrients

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1485 ◽  
Author(s):  
Alisheikh A. Atta ◽  
Kelly T. Morgan ◽  
Said A. Hamido ◽  
Davie M. Kadyampakeni ◽  
Kamal A. Mahmoud
Keyword(s):  
Leaf Area ◽  
Sap Flow ◽  
Untreated Control ◽  
Soil Nutrient ◽  
Irrigation Scheduling ◽  
Summer Season ◽  
Stem Water Potential ◽  
Area Index ◽  
Available N ◽  
Citrus Trees

The decrease in the rate of inflow and outflow of water—and thereby the uptake of plant nutrients as the result of Huanglongbing (HLB or citrus greening)—leads to a decline in overall tree growth and the development of nutrient deficiencies in HLB-affected citrus trees. This study was conducted at the University of Florida, Southwest Florida Research and Education Center (SWFREC) near Immokalee, FL from January 2017 through December 2019. The objective of the study was to determine the effect of rootstocks, nutrient type, rate, and frequency of applications on leaf area index (LAI), water relations (stomatal conductance [gs], stem water potential [Ψw], and sap flow), soil nutrient accumulation, and dynamics under HLB-affected citrus trees. The experiment was arranged in a split-split plot design that consisted of two types of rootstocks, three nitrogen (N) rates, three soil-applied secondary macronutrients, and an untreated control replicated four times. LAI significantly increased in response to the secondary macronutrients compared with uncontrolled trees. A significantly greater gs, and thus a decline in Ψw, was a manifestation of higher sap flow per unit LA (leaf area) and moisture stress for trees budded on Swingle (Swc) than Cleopatra (Cleo) rootstocks, respectively. The hourly sap flow showed significantly less water consumption per unit LA for trees that received a full dose of Ca or Mg nutrition than Ca + Mg treated and untreated control trees. The soil nutrient concentrations were consistently higher in the topmost soil depth (0–15 cm) than the two lower soil depths (15–30 cm, 30–45 cm). Mobile nutrients: soil nitrate–nitrogen (NO3-N) and Mg2+ Mg2+, Mn2+, Zn2+, and B leached to the lower soil (15–30 cm) depth during the summer season. However, the multiple split applications of N as Best Management Practices (BMPs) and optimum irrigation scheduling based on reference evapotranspiration (ETo) maintained soil available N (ammonium nitrogen [NH4-N] and NO3-N) below 4.0 mg kg−1, which was a magnitude 2.0–4.0× less than the conventional N applications. Soil NH4-N and NO3-N leached to the two lower soil depths during the rainy summer season only when trees received the highest N rate (280 kg ha−1), suggesting a lower citrus N requirement. Therefore, 224 kg ha−1 N coupled with a full Ca or Mg dose could be the recommended rate for HLB-affected citrus trees.

scholarly journals Evaluation of Soil Water Content Measurements with Capacitance Probes to Support Irrigation Scheduling in a “Red Beaut” Japanese Plum Orchard

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1757
Author(s):  
Sandra Millán ◽  
Carlos Campillo ◽  
Antonio Vivas ◽  
María José Moñino ◽  
Maria Henar Prieto
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Irrigation Management ◽  
Irrigation Scheduling ◽  
Successful Implementation ◽  
Stem Water Potential ◽  
Japanese Plum

Advances in electromagnetic sensor technologies in recent years have made automated irrigation scheduling a reality through the use of state-of-the-art soil moisture sensing devices. However, correct sensor positioning and interpretation of the measurements are key to the successful implementation of these management systems. The aim of this study is to establish guidelines for soil moisture sensor placement to support irrigation scheduling, taking into account the physiological response of the plant. The experimental work was carried out in Vegas Bajas del Guadiana (Extremadura, Spain) on a drip-irrigated experimental orchard of the early-maturing Japanese plum cultivar “Red Beaut”. Two irrigation treatments were established: control and drying. The control treatment was scheduled to cover crop water needs. In the drying treatment, the fruit trees were irrigated as in control, except in certain periods (preharvest and postharvest) in which irrigation was suspended (drying cycles). Over 3 years (2015–2017), a series of plant parameters were analyzed in relation to the measurements provided by a battery of frequency domain reflectometry probes installed in different positions with respect to tree and dripper: midday stem water potential (Ψstem), sap flow, leaf stomatal conductance, net leaf photosynthesis and daily fraction of intercepted photosynthetically active radiation. After making a comparison of these measurements as indicators of plant water status, Ψstem was found to be the physiological parameter that detected water stress earliest. The drying cycles were very useful to select the probe positions that provided the best information for irrigation management and to establish a threshold in the different phases of the crop below which detrimental effects could be caused to the crop. With respect to the probes located closest to the drippers, a drop in the relative soil water content (RSWC) below 0.2 would not be advisable for “non-stress” scheduling in the preharvest period. When no deficit irrigation strategies are applied in the postharvest period, the criteria are similar to those of preharvest. However, the probes located between the dripper at 0.15 and 0.30 m depth provide information on moderate water stress if the RSWC values falls below 0.2. The severe tree water stress was detected below 0.1 RSWC in probes located at 60 cm depth from this same position.

Effect of Limited Irrigation on Water Consumption and Grain Yield of Spring Maize (Zea Mays)

2013 ◽  
Vol 404 ◽  
pp. 415-419
Author(s):  
Heng Jia Zhang ◽  
Jun Hui Li
Keyword(s):  
Grain Yield ◽  
Soil Water ◽  
Leaf Area ◽  
Water Use ◽  
Water Consumption ◽  
Irrigation Management ◽  
Grain Filling ◽  
Total Water ◽  
Area Index ◽  
Spring Maize

The soil water contents in spring maize field were monitored continuously using soil neutron probe combined with drying-weighing method. Meanwhile, the effect of limited irrigation on crop periodic water consumption and its percentage in total water use, leaf area index, and grain yield of spring maize were explored. The results indicated that both the periodic water consumption and its percentage in total water use varied from low to high then to low within maize growing season, with the maximum valued both at silking to middle grain filling. In addition, leaf area indexes were greatly improved by full irrigation before maize filling, and grain yield was not reduced by efficient limited irrigation management, contrarily, yield increase and 31.1% of significant irrigation water saving were achieved, which was beneficial to the optimization of soil water ecological processing and limited irrigation management.

scholarly journals Estimation of Corn Leaf Area Index and Ground Cover With Vegetation Indices as a Result of Irrigation Dose

2020 ◽  
Vol 12 (12) ◽  
pp. 234
Author(s):  
C. D. Papanikolaou ◽  
M. A. Sakellariou-Makrantonaki
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Soil Cover ◽  
Vegetation Indices ◽  
Irrigation Treatment ◽  
Irrigation Scheduling ◽  
Growth Stages ◽  
Area Index ◽  
The Third ◽  
Average Maximum

New technologies have been implemented in the agricultural sector to improve crop production and resource management including irrigation water. A three-year long project was conducted to determine whether vegetation indices (VIs) could be used to estimate the leaf area index (LAI) as well as the soil cover fraction (fc) at different crop growth stages in order to use these parameters in a future study concerning irrigation through drones. A low cost unmanned aerial vehicle (drone) and a multispectral camera were used to calculate different VIs of corn (Zea mays). The irrigation scheduling based on the FAO Penman-Monteith equation and the drip irrigation method were used. Three treatments were organized in three replications and the irrigation doses were equal to 100%, 75%, and 50% of the daily evapotranspiration respectively. The Simple and Multiple Regression analysis were used and different equations were formed where the VIs were the predictor variables and the LAI and fc the predicted ones. According to the two-year period data (2018-2019), during 2018 the average maximum LAI in the full irrigation treatment (100%) was 4.1. In the medium irrigation treatment (75%) the LAI was 4.0. The LAI in the third treatment (50%) was 3.9. In 2019, the LAI was 3.7 (100% treatment). In the second treatment, the LAI was 3.3. The LAI in the third treatment was 3.0. According to the results different VIs and prediction equations could be used to estimate the LAI values with high accuracy with the in situ measurements as well as the soil cover fraction.

scholarly journals Irrigation Scheduling with Soil Gas Diffusivity as a Decision Tool to Mitigate N2O Emissions from a Urine-Affected Pasture

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 443
Author(s):  
Camille Rousset ◽  
Timothy J. Clough ◽  
Peter R. Grace ◽  
David W. Rowlings ◽  
Clemens Scheer
Keyword(s):  
Irrigation Management ◽  
Irrigation Treatment ◽  
Irrigation Scheduling ◽  
Soil Gas ◽  
N2o Emissions ◽  
Irrigation Frequency ◽  
Water Demands ◽  
Gas Diffusivity ◽  
Matter Production ◽  
Access To Water

Pastures require year-round access to water and in some locations rely on irrigation during dry periods. Currently, there is a dearth of knowledge about the potential for using irrigation to mitigate N2O emissions. This study aimed to mitigate N2O losses from intensely managed pastures by adjusting irrigation frequency using soil gas diffusivity (Dp/Do) thresholds. Two irrigation regimes were compared; a standard irrigation treatment based on farmer practice (15 mm applied every 3 days) versus an optimised irrigation treatment where irrigation was applied when soil Dp/Do was ≈0.033 (equivalent to 50% of plant available water). Cow urine was applied at a rate of 700 kg N ha−1 to simulate a ruminant urine deposition event. In addition to N2O fluxes, soil moisture content was monitored hourly, Dp/Do was modelled, and pasture dry matter production was measured. Standard irrigation practices resulted in higher (p = 0.09) cumulative N2O emissions than the optimised irrigation treatment. Pasture growth rates under treatments did not differ. Denitrification during re-wetting events (irrigation and rain) contributed to soil N2O emissions. These results warrant further modelling of irrigation management as a mitigation option for N2O emissions from pasture soils, based on Dp/Do thresholds, rainfall, plant water demands and evapotranspiration.

scholarly journals Remote Sensing to Study Mangrove Fragmentation and Its Impacts on Leaf Area Index and Gross Primary Productivity in the South of Peninsular Malaysia

2021 ◽  
Vol 13 (8) ◽  
pp. 1427
Author(s):  
Kasturi Devi Kanniah ◽  
Chuen Siang Kang ◽  
Sahadev Sharma ◽  
A. Aldrie Amir
Keyword(s):  
Remote Sensing ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Primary Productivity ◽  
Peninsular Malaysia ◽  
Area Index ◽  
Mangrove Area ◽  
The Mean ◽  
Shape Complexity ◽  
The Impact

Mangrove is classified as an important ecosystem along the shorelines of tropical and subtropical landmasses, which are being degraded at an alarming rate despite numerous international treaties having been agreed. Iskandar Malaysia (IM) is a fast-growing economic region in southern Peninsular Malaysia, where three Ramsar Sites are located. Since the beginning of the 21st century (2000–2019), a total loss of 2907.29 ha of mangrove area has been estimated based on medium-high resolution remote sensing data. This corresponds to an annual loss rate of 1.12%, which is higher than the world mangrove depletion rate. The causes of mangrove loss were identified as land conversion to urban, plantations, and aquaculture activities, where large mangrove areas were shattered into many smaller patches. Fragmentation analysis over the mangrove area shows a reduction in the mean patch size (from 105 ha to 27 ha) and an increase in the number of mangrove patches (130 to 402), edge, and shape complexity, where smaller and isolated mangrove patches were found to be related to the rapid development of IM region. The Moderate Resolution Imaging Spectro-radiometer (MODIS) Leaf Area Index (LAI) and Gross Primary Productivity (GPP) products were used to inspect the impact of fragmentation on the mangrove ecosystem process. The mean LAI and GPP of mangrove areas that had not undergone any land cover changes over the years showed an increase from 3.03 to 3.55 (LAI) and 5.81 g C m−2 to 6.73 g C m−2 (GPP), highlighting the ability of the mangrove forest to assimilate CO2 when it is not disturbed. Similarly, GPP also increased over the gained areas (from 1.88 g C m−2 to 2.78 g C m−2). Meanwhile, areas that lost mangroves, but replaced them with oil palm, had decreased mean LAI from 2.99 to 2.62. In fragmented mangrove patches an increase in GPP was recorded, and this could be due to the smaller patches (<9 ha) and their edge effects where abundance of solar radiation along the edges of the patches may increase productivity. The impact on GPP due to fragmentation is found to rely on the type of land transformation and patch characteristics (size, edge, and shape complexity). The preservation of mangrove forests in a rapidly developing region such as IM is vital to ensure ecosystem, ecology, environment, and biodiversity conservation, in addition to providing economical revenue and supporting human activities.

scholarly journals ANÁLISE DE CRESCIMENTO EM CLONES DE EUCALIPTO SUBMETIDOS A ESTRESSE HÍDRICO

Irriga ◽  
2010 ◽  
Vol 15 (1) ◽  
pp. 98-110 ◽  
Author(s):  
Maria Renata Rocha Pereira ◽  
Guilherme Sasso Ferreira Souza ◽  
Andreia Cristina Peres Rodrigues ◽  
Andre Luiz Melhorança Filho ◽  
Antonio Evaldo Klar
Keyword(s):  
Soil Water ◽  
Leaf Area ◽  
Genetic Material ◽  
Area Index ◽  
Growth Ratio ◽  
Relative Growth ◽  
Water Potentials ◽  
Absolute Growth ◽  
Hydric Stress ◽  
East West

O estudo objetivou avaliar o desempenho de genótipos de plantas de Eucalyptus urograndis (clone 105 e 433) em relação à tolerância à seca, considerando a análise de crescimento das plantas. Para tanto, plantas foram cultivadas em vasos de 8 litros em casa de vegetação. O delineamento foi em inteiramente casualizado, com quatro tratamentos contendo desesseis repetições. O manejo hídrico foi estabelecido com base em dois potenciais mínimos de água (Ψ): -0,03 e -1,5 MPa, através da pesagem diária dos vasos. O desenvolvimento das plantas foi avaliado em coletas a intervalos de 15 dias, iniciando no momento de plantio da muda no vaso até os 60 dias após plantio. Considerando-se o acúmulo de matéria seca total (MS) e o índice de área foliar da planta (IAF) como base para a determinação dos seguintes índices fisiológicos: razão de área foliar (RAF), taxa assimilatória líquida (TAL), área foliar específica (AFE), taxa de crescimento relativo (TCR) e taxa de crescimento absoluto (TCA). Nas condições do experimento, o clone 105 apresentou menor sensibilidade ao déficit hídrico, o que o qualifica como material genético promissor para ambientes sujeitos a estiagem prolongada. Já em condições em que não há restrição hídrica, os dois clones tiveram comportamento semelhantes.   UNITERMOS: Eucaliptus urograndis, índices fisiológicos, potenciais hídricos do solo     PEREIRA, M. R. R.; SOUZA, G. S. F. de; RODRIGUES, A. C. P.; MELHORANÇA FILHO, A. L.; KLAR, A. E. GROWTH ANALYSIS OF CLONE EUCALIPTUS UNDER HYDRIC STRESS     2 ABSTRACT   The aim of this study was to evaluate Eucaliptus grandis genotypes (Clones 105 and 433) in relation to drought  tolerance, through growth plant analysis.  Black PVC pots with 10 liter volume were used for cultivate plants in polyethilene greenhouse oriented east/west. Completely randonmized design with four treatments was used: two clones and two minimum soil water  potentials ( - 0.03 and -1,5 MPa) and sixteen replicates.  Pots were weighed daily in order to evaluate water content and characteristic soli water curve was determined. Plant development was obtained each 15 days from planting until 60 days  through  total dry matter (DM), leaf area index (LAI),  leaf area ratio (LAR), net assimilative ratio (NAR), specific leaf area (SLA), relative growth ratio (RGR) and absolute growth ratio (AGR). Results showed that clone 105 presented less sensibility to water deficit, which qualify it as genetic material for use under dry soil conditons.  On the other hand, both clones had similar behavior with no water restrictions.   KEYWORDS: Eucaliptus grandis, soil water potentials, morphologic measurements.  

scholarly journals Measurement of grapevine canopy leaf area by using an ultrasonic-based method

OENO One ◽  
2013 ◽  
Vol 47 (3) ◽  
pp. 183 ◽  
Author(s):  
Marco Vitali ◽  
Mario Tamagnone ◽  
Tiziana La Iacona ◽  
Claudio Lovisolo
Keyword(s):  
Leaf Area ◽  
Large Scale ◽  
Irrigation Management ◽  
Management Training ◽  
Ultrasonic Sensors ◽  
Leaf Sample ◽  
Area Index ◽  
Canopy Area ◽  
Point Quadrat ◽  
Leaf Canopy

<p style="text-align: justify;"><strong>Aim</strong>: Measurement of leaf area in grapevine has always been a critical point in researches focused on irrigation management, training systems, source-sink interrelationships and efficiency of spray application to canopies. In this work, we propose the use of ultrasonic sensors as a fast and accurate tool for the estimation of large portions of leaf canopy area.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Through outputs of ultrasonic sensors installed on a tractor moving along vineyard rows, we calculated an ultrasonic-based leaf density index that we correlated with three measurements or estimates of canopy area: I) direct measurement of the area of a canopy portion (LAØ), assessed by summing the areas of all the leaves, where each single-leaf area was assessed by regressing the leaf diameter (the maximum width perpendicular to the main rip) against the related leaf area calculated on the basis of a relation between the leaf diameter and the leaf area, previously assessed through an area meter on a 20-leaf sample; II) the point quadrat output (LApq); and III) the canopy leaf area index (LAI) obtained through LAI-2000 (Li-Cor) technology. The measurements were assessed on six cultivars in three replicate rows (8-12 plants per cultivar per row) in a vineyard trained to a vertical trellis system.</p><p style="text-align: justify;"><strong>Conclusion</strong>: When we correlated the three independent control parameters with each other, we obtained highly significant correlations between LApq and LAØ, but less significant correlations between these two and LAI-2000 outputs. Also, the correlations between ultrasonic outputsoutputs and LAØ and LApq were significant, with R2 ranging between 0.84 and 0.85. On the contrary, no significant correlation was found between ultrasonic outputs and LAI-2000 outputs. These results were obtained by averaging all the values belonging to each replicated cultivar (10.5 m along the row, i.e., twelve contiguous vines); on the contrary, when the analysis was done over a shorter distance (3.5 m, i.e., four contiguous vines), the reliability of the ultrasonic-based method decreased.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: These results point to the ultrasonic technology as a powerful tool to estimate large-scale leaf canopy area, with potential applications in precision farming. At the moment, however, the limitation of this approach is the requirement of reference values for leaf area (e.g., assessed by point quadrat) to obtain absolute and not only relative outputs. With this application we can quantify, in a few hours, the canopy of a whole vineyard, in order to analyze different vegetation zones or to follow canopy development.</p>

The Impact of Noah-MP Physical Parameterizations on Modeling Water Availability during Droughts in the Texas-Gulf Region

2021 ◽  
Author(s):  
Wen-Ying Wu ◽  
Zong-Liang Yang ◽  
Michael Barlage
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Water Availability ◽  
Water Storage ◽  
Rooting Depth ◽  
Surface Model ◽  
Terrestrial Water Storage ◽  
Area Index ◽  
Terrestrial Water ◽  
The Impact

AbstractTexas is subject to severe droughts, including the record-breaking one in 2011. To investigate the critical hydrometeorological processes during drought, we use a land surface model, Noah-MP, to simulate water availability and investigate the causes of the record drought. We conduct a series of experiments with runoff schemes, vegetation phenology, and plant rooting depth. Observation-based terrestrial water storage, evapotranspiration, runoff, and leaf area index are used to compare with results from the model. Overall, the results suggest that using different parameterizations can influence the modeled water availability, especially during drought. The drought-induced vegetation responses not only interact with water availability but also affect the ground temperature. Our evaluation shows that Noah-MP with a groundwater scheme produces a better temporal relationship in terrestrial water storage compared with observations. Leaf area index from dynamic vegetation is better simulated in wet years than dry years. Reduction of positive biases in runoff and reduction of negative biases in evapotranspiration are found in simulations with groundwater, dynamic vegetation, and deeper rooting zone depth. Multi-parameterization experiments show the uncertainties of drought monitoring and provide a mechanistic understanding of disparities in dry anomalies.

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