scholarly journals (3) Comparability of Nutrient and Water Management Strategies for Seepage-irrigated Watermelon in South Florida

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1014D-1015
Author(s):  
Kent Cushman ◽  
Sanjay Shukla ◽  
Gregory Hendricks ◽  
Thomas Obreza ◽  
Fritz Roka ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Management Strategy ◽  
Soil Moisture Content ◽  
The United States ◽  
South Florida ◽  
Soluble Solids ◽  
High Rate ◽  
Experimental Unit ◽  
Seepage Irrigation

Florida is one of the leading states in the United States in watermelon production, and on-farm management of nutrients and water is an important issue in the state. A management strategy using higher-than-recommended rates was compared to two strategies using recommended rates. A systems approach was used to define treatments: (HR) high rate of 265 pounds per acre (lb/ac) N, 170 lb/ac P2O5, 459 lb/ac K2O, and soil moisture content of 16% to 20% via seepage irrigation, (RR) recommended rate of 150 lb/ac N, 100 lb/ac P2O5, 150 lb/ac K2O, and soil moisture content of 8% to 12% via seepage irrigation, and (RR-S) equal to RR but irrigation provided by subsurface drip tubing. Large quarter-acre plots were used for each experimental unit. `Tri-X 313' was interplanted with `Mardi Gras' during Spring 2004 and with `SP-1' during Spring 2005 in a RCB design with two replications at the SWFREC in Immokalee. Leaf tissue analyses, petiole sap, and biomass accumulation were recorded each season. Watermelons were harvested at least twice each year and fruit were counted and weighed individually from three subplots within each plot. At least five fruit from each subplot were cut open for internal evaluation. Leaf nitrogen and potassium content for HR was consistently greater than that of RR or RR-S. Yields of HR were 41% to 50% greater than the two RR treatments. Yield was 1089, 704, and 775 hundred-pound units per acre (cwt/ac) in 2004 and 801, 541, and 533 cwt/ac in 2005 for HR, RR, and RR-S, respectively. Soluble solids content and hollowheart incidence were not affected by treatment. Our results indicate HR was more productive than RR or RR-S and may justify the higher inputs associated with this management strategy.

Salmonella Survival in Soil and Transfer Onto Produce via Splash Events

2019 ◽  
Vol 82 (12) ◽  
pp. 2023-2037 ◽  
Author(s):  
DEBBIE LEE ◽  
MOUKARAM TERTULIANO ◽  
CASEY HARRIS ◽  
GEORGE VELLIDIS ◽  
KAREN LEVY ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Geometric Mean ◽  
The United States ◽  
Mean Difference ◽  
Antecedent Soil Moisture ◽  
Produce Safety ◽  
Produce Contamination ◽  
Salmonella Survival

ABSTRACT Nearly one-half of foodborne illnesses in the United States can be attributed to fresh produce consumption. The preharvest stage of production presents a critical opportunity to prevent produce contamination in the field from contaminating postharvest operations and exposing consumers to foodborne pathogens. One produce-contamination route that is not often explored is the transfer of pathogens in the soil to edible portions of crops via splash water. We report here on the results from multiple field and microcosm experiments examining the potential for Salmonella contamination of produce crops via splash water, and the effect of soil moisture content on Salmonella survival in soil and concentration in splash water. In field and microcosm experiments, we detected Salmonella for up to 8 to 10 days after inoculation in soil and on produce. Salmonella and suspended solids were detected in splash water at heights of up to 80 cm from the soil surface. Soil-moisture conditions before the splash event influenced the detection of Salmonella on crops after the splash events—Salmonella concentrations on produce after rainfall were significantly higher in wet plots than in dry plots (geometric mean difference = 0.43 CFU/g; P = 0.03). Similarly, concentrations of Salmonella in splash water in wet plots trended higher than concentrations from dry plots (geometric mean difference = 0.67 CFU/100 mL; P = 0.04). These results indicate that splash transfer of Salmonella from soil onto crops can occur and that antecedent soil-moisture content may mediate the efficiency of microbial transfer. Splash transfer of Salmonella may, therefore, pose a hazard to produce safety. The potential for the risk of splash should be further explored in agricultural regions in which Salmonella and other pathogens are present in soil. These results will help inform the assessment of produce safety risk and the development of management practices for the mitigation of produce contamination. HIGHLIGHTS

scholarly journals Root Regeneration of Fall-Lifted White Spruce Nursery Stock in Relation to Soil Moisture Content

1975 ◽  
Vol 51 (5) ◽  
pp. 196-199 ◽  
Author(s):  
R. J. Day ◽  
G. R. MacGillivray
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Root Elongation ◽  
Soil Moisture Content ◽  
Field Capacity ◽  
White Spruce ◽  
Moisture Stress ◽  
High Rate ◽  
Root Regeneration ◽  
Nursery Stock

The root regenerating potential of fall-lifted 2+0 white spruce nursery stock is described after transplanting into soil-maintained at 8, 10 and 15% soil moisture content (SMC) in glass fronted root boxes. At 15% SMC (0.1 bar soil moisture tension), which is close to field capacity, root regeneration began 10 days after transplanting and root elongation continued at a high rate for the remainder of a 40-day study period. At 10% SMC (0.6 bar SMT) root regeneration was delayed until 20 days after transplanting and root elongation was at a slower rate. At 8% SMC (1.5 bars) root regeneration and elongation was negligible. Plant moisture stress measured at 40 days was least when root regeneration was most and vice versa. The results suggest that field planting of white spruce in soils with moisture tensions of over 0.6 bar will be hazardous.

scholarly journals Florida Watermelon Production Affected by Water and Nutrient Management

2007 ◽  
Vol 17 (3) ◽  
pp. 328-335 ◽  
Author(s):  
Gregory S. Hendricks ◽  
Sanjay Shukla ◽  
Kent E. Cushman ◽  
Thomas A. Obreza ◽  
Fritz M. Roka ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Citrullus Lanatus ◽  
Block Design ◽  
Soluble Solids ◽  
Plant Performance ◽  
Management Approach ◽  
Total Biomass ◽  
Total N

Watermelon (Citrullus lanatus) production is concentrated in southern Florida where growers often use seepage irrigation. According to a recent survey, growers believe that nitrogen (N), phosphorus (P), and potassium (K) rates recommended by the University of Florida Institute of Food and Agricultural Sciences (UF-IFAS) are low. A study was conducted during Spring 2004 and 2005 at a UF-IFAS research farm to compare three nutrient and water management systems: high rate [HR (265, 74, and 381 lb/acre N, P, and K, respectively)], recommended rate [RR (150, 44, and 125 lb/acre N, P, and K, respectively)], and recommended rate with subsurface irrigation (RR-S). Irrigation was managed to keep soil moisture content at 16% to 20% for HR and 8% to 12% for RR and RR-S. The experimental design was a randomized complete block design with two replications and three subsample areas within each 0.25-acre plot. The HR management approach produced ≈60% to 80% higher yields (cwt/acre) during 2005 than RR or RR-S. The HR treatment produced larger watermelons than RR or RR-S in 2005. Triploid watermelon prices had to be at least $3.74/cwt to cover all costs associated with HR. The HR approach increased the grower net returns by $590/acre and $1764/acre under conservative and higher yield and price expectations, respectively. Soluble solids content and hollowheart ratings were unaffected by treatment. Total biomass, recorded during 2005, followed a similar trend as yield, with HR producing 105% and 125% greater total dry weight than RR and RR-S, respectively. Total N content of HR biomass was 56% higher than that of RR and RR-S. Total P content was 29% and 50% higher than that of RR and RR-S, respectively. Leaf and petiole tissue from the HR treatment exhibited consistently higher N and K leaf tissue values during 2005 than RR and RR-S. In conclusion, trends in the data consistently showed greater plant performance with higher rates of fertilizer and soil moisture content. Our ability to detect differences in 2005 was probably enhanced by higher rainfall during 2005 compared with 2004.

Experimental Embryonation and Survival of Eggs of Capillaria-Hepatica (Nematoda) Under Mouse Burrow Conditions in Cereal-Growing Soils

1987 ◽  
Vol 35 (4) ◽  
pp. 337 ◽  
Author(s):  
DM Spratt ◽  
GR Singleton
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
High Rate ◽  
Capillaria Hepatica ◽  
South Eastern ◽  
Eastern Australia ◽  
Soil Temperatures ◽  
Main Period ◽  
South Eastern Australia

The apparent absence of the nematode Capillaria hepatica in mice from regions of south-eastern Australia where plagues occur may be due to constraints on embryonation and survival of eggs in the mouse burrow, where C. hepatica is thought to be transmitted. Excavation of mouse burrows in the mallee wheatlands indicated that nest chambers generally were at depths of 200-400 mm. At these depths minimum and maximum weekly soil temperatures during the main period of mouse breeding ranged from 15 to 36.5�C and soil moisture contents were 14.5-32.8%. Embryonation and survival of C. hepatica eggs were assessed in the laboratory in three types of soil over these ranges of soil temperature and soil moisture content, emulating conditions of the mouse burrow. Two of the soil types, Walpeup sandy loan and Deniliquin riverine clay, are representative of the light and heavy soils, respectively, where mouse plagues occur in south-eastern Australia. The third type of soil was a potting mixture previously used experimentally and known to support a high rate of transmission of C. hepatica. Eggs were able to embryonate, and embryonated eggs to survive for 30 days, in each type of soil across the ranges of temperature and moisture content. The results further support the potential of C. hepatica to be used tactically in suppressing mouse numbers in the cereal-growing regions of south-eastern Australia.

scholarly journals Effects of Water Immersion and Soil Moisture Content on Larval and Pupal Survival of Bactrocera minax (Diptera: Tephritidae)

Insects ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 138 ◽  
Author(s):  
Zaiyuan Li ◽  
Consolatha Chambi ◽  
Tianhua Du ◽  
Cong Huang ◽  
Fulian Wang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Soil Moisture Content ◽  
Southern China ◽  
Water Immersion ◽  
High Water ◽  
High Rate ◽  
High Water Content ◽  
Respiration Rates

Bactrocera minax, one of the most devastating citrus pests in Asia, has two developmental stages (mature larva and pupa) that complete their life cycle in the soil. Currently, southern China has a climate with abundant autumn rains, and soil moisture can be a major factor affecting the survival of larvae and pupae of B. minax. In the present study, we evaluated the effects of water immersion and high soil moisture content on the development of mature larvae and pupae of B. minax. When immersed in water for 1 d, 100% of mature larvae of B. minax were knocked out. When larvae were immersed for less than 6 d, however, more than 92% of knocked-out larvae recovered within 24 h. The days of water immersion with 50% and 90% recovery ratios (indicated as RD50 and RD90) were 10.3 d and 6.4 d, respectively. When larvae were immersed less than 6 d, the mortality ratios of larvae were not significantly different from those that were not immersed at all. The days of immersion causing 50% and 90% mortality of larvae (MD50 and MD90, respectively) were 7.6 d and 11.1 d, respectively. The pupation ratios of larvae were also observed to be not significantly different compared to non-immersion, and the days of immersion causing 50% and 90% pupation (PD50 and PD90, respectively) were 6.6 d and 0.8 d, respectively. Larval respiration rates were reduced after water immersion as a strategy for larval survival. High water content was not detrimental to pupae of B. minax. Adult emergence did not significantly decrease in soil with high water content, even though pupae were under those conditions for 161–175 d. The respiration rates of pupae were lower in soil with different moisture levels and were not significantly different, which ensured the survival of pupae in high water content. Reduced respiration rate is a strategy for survival of larvae and pupae, and remarkable tolerance to high moisture conditions could explain the high rate of spread and geographical distribution of B. minax. The results of this study provide a reference for the occurrence and control of B. minax.

High-rate GNSS Reflectometry Estimates for Airborne Soil-moisture Detection

2021 ◽  
Author(s):  
Hamza Issa ◽  
Georges Stienne ◽  
Serge Reboul ◽  
Maximilian Semmling ◽  
Mohamad Raad ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Elevation Angle ◽  
High Rate ◽  
Area Of Interest ◽  
Gnss Reflectometry ◽  
Low Altitude ◽  
Reflecting Surface

<p>Soil moisture remote sensing on a global scale has been an active area of research over the past few decades due to its essential role in agriculture and in the prediction of some natural disasters. In this regard, GNSS-Reflectometry (GNSS-R) is proven as an efficient tool for the measurement of soil moisture content using remote sensing techniques. GNSS-R is a bi-static radar technique that uses the L-band GNSS signals as sources of opportunity to characterize Earth's surface, due to the fact that the reflected signals are often affected by the properties of the reflecting surface. In the context of this work, it is important to detect and fastly reach the area of interest (reflecting surface) for which the soil moisture content shall be monitored. A GNSS-R setup onboard a gyrocopter meets all the requirements of our application. This paper is dedicated to the study of airborne GNSS-R techniques for soil moisture monitoring using a low-altitude airborne carrier with a high rate (1ms for GPS C/A) carrier-to-noise ratio (C/N<sub>0</sub>) observations. </p><p>To cope with the rapid displacement of the satellites footprints along the receiver trajectory, high rate (1000 Hz rate) C/N<sub>0</sub> observations are processed. For this purpose, real flight experimentation has taken place on October 19, 2020 for 45 min. During the flight, the gyrocopter maintained a low-altitude of approximately 315m above the ground with an average speed of 95 km/h. Based on that, the size of the major axis of the first Fresnel zones that constitute the detected footprints ranged between 1,316m for a minimum elevation angle of 3<sup>°</sup> and 15m for a maximum elevation angle of 75°. Concerning the temporal resolution of the application, the raw data were sampled at a frequency of 25MHz and the C/N<sub>0</sub> estimates were realized at a rate of 1000Hz.</p><p>During the flight, an average of 9 GPS satellites have been detected of which 4 GPS satellite signals were extensively analyzed to observe the reflectivity corresponding to land, beach, and sea reflections. After analyzing the Delay Doppler Maps which provides an image of the scattering cross-section in terms of time and frequency and consequently tracking the corresponding signals, the 1ms C/N<sub>0 </sub>estimations were derived using the in-phase components of the signals as observations. The reflected signals are then linked to the footprints of the satellites and thus to the reflecting surfaces from which each processed signal has reflected using the GPS time, attitude, and position provided by onboard sensors and the GPS time extracted from the digitized GNSS signals. The ultimate aim of this study is to obtain reflectivity measurements from high rate C/N<sub>0</sub> observations in order to provide a soil moisture mapping of the studied area, where we notice that the signals reflected from the beach had the best reflectivity followed by sea then land reflections.</p>

Analysis on Soil Moisture Content in the Middle Reaches of the Yellow River

2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Yellow River ◽  
The Yellow River

Distribution of soil moisture content and its effect on the potential growth of the over-story species in North-East Chalkidiki

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Depth ◽  
Moisture Distribution ◽  
Taxus Baccata ◽  
Mixed Stands ◽  
Potential Growth ◽  
North East ◽  
Soil Moisture Distribution

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.

scholarly journals Mapping barrier island soil moisture using a radiative transfer model of hyperspectral imagery from an unmanned aerial system

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rehman S. Eon ◽  
Charles M. Bachmann
Keyword(s):  
Soil Moisture ◽  
Radiative Transfer ◽  
Moisture Content ◽  
Layer Thickness ◽  
Soil Moisture Content ◽  
Hyperspectral Imagery ◽  
Barrier Island ◽  
Water Layer ◽  
Radiative Transfer Model ◽  
Transfer Model

AbstractThe advent of remote sensing from unmanned aerial systems (UAS) has opened the door to more affordable and effective methods of imaging and mapping of surface geophysical properties with many important applications in areas such as coastal zone management, ecology, agriculture, and defense. We describe a study to validate and improve soil moisture content retrieval and mapping from hyperspectral imagery collected by a UAS system. Our approach uses a recently developed model known as the multilayer radiative transfer model of soil reflectance (MARMIT). MARMIT partitions contributions due to water and the sediment surface into equivalent but separate layers and describes these layers using an equivalent slab model formalism. The model water layer thickness along with the fraction of wet surface become parameters that must be optimized in a calibration step, with extinction due to water absorption being applied in the model based on equivalent water layer thickness, while transmission and reflection coefficients follow the Fresnel formalism. In this work, we evaluate the model in both field settings, using UAS hyperspectral imagery, and laboratory settings, using hyperspectral spectra obtained with a goniometer. Sediment samples obtained from four different field sites representing disparate environmental settings comprised the laboratory analysis while field validation used hyperspectral UAS imagery and coordinated ground truth obtained on a barrier island shore during field campaigns in 2018 and 2019. Analysis of the most significant wavelengths for retrieval indicate a number of different wavelengths in the short-wave infra-red (SWIR) that provide accurate fits to measured soil moisture content in the laboratory with normalized root mean square error (NRMSE)< 0.145, while independent evaluation from sequestered test data from the hyperspectral UAS imagery obtained during the field campaign obtained an average NRMSE = 0.169 and median NRMSE = 0.152 in a bootstrap analysis.

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