scholarly journals Increased signal to noise ratios within experimental field trials by regressing spatially distributed soil properties as principal components.

2021 ◽  
Author(s):  
Jeffrey C Berry ◽  
Mingsheng Qi ◽  
Balasaheb V Sonawane ◽  
Amy Sheflin ◽  
Asaph Cousins ◽  
...  
Keyword(s):  
Soil Properties ◽  
Degrees Of Freedom ◽  
Environmental Variability ◽  
Plant Traits ◽  
Experimental System ◽  
Environmental Variation ◽  
Field Studies ◽  
Field Trials ◽  
Spatially Distributed ◽  
Sorghum Genotypes

Environmental variability poses a major challenge to any field study. Researchers attempt to mitigate this challenge through replication. Thus, the ability to detect experimental signals is determined by the degree of replication and the amount of environmental variation, noise, within the experimental system. A major source of noise in field studies comes from the natural heterogeneity of soil properties which create micro-treatments throughout the field. To make matters worse, the variation within different soil properties is often non-randomly distributed across a field. We explore this challenge through a sorghum field trial dataset with accompanying plant, microbiome and soil property data. Diverse sorghum genotypes and two watering regimes were applied in a split-plot design. We describe a process of identifying, estimating, and controlling for the effects of spatially distributed soil properties on plant traits and microbial communities using minimal degrees of freedom. Importantly, this process provides a tool with which sources of environmental variation in field data can be identified and removed, improving our ability to resolve effects of interest and to quantify subtle phenotypes.

scholarly journals Managing Bees for Delivering Biological Control Agents and Improved Pollination in Berry and Fruit Cultivation

2015 ◽  
Vol 4 (3) ◽  
pp. 89 ◽  
Author(s):  
Heikki M. T. Hokkanen ◽  
Ingeborg Menzler-Hokkanen ◽  
Marja-Leena Lahdenpera
Keyword(s):  
Crop Protection ◽  
Field Tests ◽  
Weather Conditions ◽  
Field Studies ◽  
Field Trials ◽  
Marketable Yield ◽  
Dissemination Activity ◽  
Grey Mold ◽  
Commercial Farms ◽  
Disease Pressure

<p>Targeted precision biocontrol and improved pollination were studied Europe-wide in the EU ERA-NET CORE ORGANIC 2 project BICOPOLL (Biocontrol and Pollination). A case study was conducted on the management of strawberry grey mold <em>Botrytis cinerea</em>, with the biocontrol fungus, <em>Gliocladium catenulatum</em>, vectored by honey bees or bumble bees. A joint field trial carried out in five countries targeted strawberry cultivations in open field, and included four treatments: untreated control, chemical fungicide, entomovectored biocontrol, and chemical and biocontrol combined. In organic fields, no pesticide treatments were included. The proportion of moldy berries, and/or the marketable yield of healthy berries were recorded from each treatment, along with other parameters of local interest. A pilot study was started in Finland in 2006, and, by 2012, large commercial farms were using entomovectoring. In 2012, field trials were started in Estonia and in Italy, and in 2013-14, these experiments were expanded to Slovenia and Turkey. In total, 26 field tests were conducted using entomovectoring and <em>Gliocladium catenulatum</em> (Prestop<sup>®</sup> Mix) on strawberry, with five additional trials on raspberry. Efficacy results have been excellent throughout the field studies. The results show crop protection equalling or exceeding that provided by a full chemical fungicide program, under all weather conditions, and over a wide geographical range (from Finland to Turkey). Under heavy disease pressure, entomovectoring provided on average a 47% disease reduction, which was the same as multiple fungicide sprays. Under light disease pressure, biocontrol decreased grey mold by an average of 66%, which was greater than fungicide sprays. The concept has proven to be effective on strawberries, raspberries, pears, apples, blueberries, cherries, and grapes. A conservative estimate for Finland is that over 500 ha of strawberry cultivation currently use the technique (≈15% of the strawberry growing area). To make full use of the entomovectoring technique, organic berry and fruit growers are encouraged to (i) keep bees, or to hire the service from local beekeepers for entomovectoring; and (ii) manage vegetation within and around the target crop to support the activity of bees and other pollinators, which can help to disseminate the beneficial microbial populations within the crop. Beekeepers are encouraged to (i) market pollination and biocontrol services to fruit and berry growers, and (ii) ensure that all operations are effective in mananging bees and their microbe dissemination activity. Biocontrol product manufacturers are encouraged to further develop products and their formulations specifically for entomovectoring, because current formulations are suboptimal as they are initially optimized for other uses (e.g., mixing into the soil).</p>

scholarly journals Optimizing Sowing Depth of Tef for Irrigated Mediterranean Conditions: From Laboratory to Field Studies

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1983
Author(s):  
Shiran Ben-Zeev ◽  
Shane Kerzner ◽  
Onn Rabinovitz ◽  
Yehoshua Saranga
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Field Trials ◽  
Eragrostis Tef ◽  
Sowing Depth ◽  
New Crops ◽  
Different Depths ◽  
Plant Emergence ◽  
Increasing Demand ◽  
Mediterranean Conditions

Developing new crops adapted to arid conditions is a promising approach to meet the increasing demand for food production under expanding aridity. Tef [Eragrostis tef (Zucc.) Trotter] is a C4 cereal crop cultivated mainly in Ethiopia and the Horn of Africa, and known for its high resilience to stressful environments. Due to their tiny size, tef seeds are traditionally sown by broadcasting and lightly covering with soil. Under semiarid Mediterranean conditions, a deeper sowing may guarantee seedling establishment while saving on irrigation water. The objective of this study was, therefore, to determine the effects of sowing depth on tef emergence, development, lodging, and productivity. Tef seeds were sown at different depths in test tubes and pots, and in two field experiments. In tubes and pots, time from sowing to emergence increased about twofold and emergence rate decreased in the deepest sowing (3 cm) treatment compared to controls (0 cm). In the pot and field trials, deep sowing (3 cm) significantly reduced plant height, shoot and root biomass, and lodging. Sowing depths of 1–2 cm allowed successful plant establishment while not exacting penalties on plant emergence or development; hence this range appears to be optimal for sowing irrigated tef.

Reliability of Singing Bird Surveys: Changes in Observer Efficiency with Avian Density

The Auk ◽  
1984 ◽  
Vol 101 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Jonathan Bart ◽  
James D. Schoultz
Keyword(s):  
Measurement Error ◽  
General Procedure ◽  
Field Studies ◽  
Abundant Species ◽  
Common Species ◽  
Field Trials ◽  
Bird Songs ◽  
Auditory Cues ◽  
Basic Assumptions ◽  
Maximum Estimate

Abstract Field trials in which paired observers were used and indoor simulations in which recorded bird songs were used indicated that, as the number of singing birds audible from a listening station increased from 1 to 4, the fraction of them recorded by observers declined by up to 50%. This reduction in efficiency violates one of the basic assumptions of any index-that the proportion of animals detected remains constant-and could cause surveyors who rely primarily on auditory cues to underestimate changes in population density by up to 25% for common species and 33% for abundant species. The change in efficiency, which is best regarded as measurement error, cannot be detected by a statistical examination of the data and thus may pass undetected in many field studies. It seems unlikely that any general procedure for "correcting" the error would be reliable. The results indicate that singing bird surveys of common species should be supplemented by other methods if accurate estimates of changes in density are needed. A general conclusion of the study is that whenever animals "compete" for a place in the survey, for example by filling up traps or suppressing one another's songs, then the index tends to underestimate a change in density. If efficiency increases with density, then the survey tends to overestimate a change in density. If the sign of the bias can be determined, the survey can be used to provide a minimum or maximum estimate of a change in density even if the magnitude of the bias cannot be estimated.

scholarly journals Influence of soil pH, rainfall, dosage, and application timing of herbicide Merlin 750 WG (isoxaflutole) on phytotoxicity level in maize (Zea mays L.)

2011 ◽  
Vol 50 (No. 2) ◽  
pp. 88-94 ◽  
Author(s):  
J. Soukup ◽  
M. Jursík ◽  
P. Hamouz ◽  
J. Holec ◽  
J. Krupka
Keyword(s):  
Soil Ph ◽  
Weight Reduction ◽  
Zea Mays L ◽  
Field Studies ◽  
Field Trials ◽  
Early Growth ◽  
Application Timing ◽  
Pot Trials ◽  
Phytotoxic Effect ◽  
Shoot Weight

Pot trials and field studies were carried out to describe the influence of soil pH and rainfall on the phytotoxic effect of the herbicide Merlin 750 WG (isoxaflutole) in maize. Symptoms as bleaching, and root and shoot weight reduction in early growth of maize were found. In pot trials, a statistically significant crop injury in early growth of maize was found only at the herbicide dose of 100 and 130 g/ha followed by 30 mm precipitation directly after herbicide application in soils with pH 6.5 and 7.2. Bleaching and significant weight reduction of maize up to growth stage BBCH 13 were observed in field trials at treatments with early post-emergence application of Merlin and 20 mm precipitations. Bleaching symptoms recovered up to BBCH 19. Significant differences were found in maize shoot weight and cob yield between treatments with and without watering (20 mm irrigation), and between pre- and post-emergence application of Merlin under field conditions. No significant differences were found between herbicide doses tested.

scholarly journals Competition Between Fusarium pseudograminearum and Cochliobolus sativus Observed in Field and Greenhouse Studies

2018 ◽  
Vol 108 (2) ◽  
pp. 215-222 ◽  
Author(s):  
Erin E. Gunnink Troth ◽  
Jeffrey A. Johnston ◽  
Alan T. Dyer
Keyword(s):  
Wheat Plant ◽  
Field Studies ◽  
Field Trials ◽  
Cochliobolus Sativus ◽  
Fusarium Spp ◽  
Fusarium Pseudograminearum ◽  
Population Sizes ◽  
Polymerase Chain ◽  
Pathogen Populations ◽  
Respective Species

Among root pathogens, one of the most documented antagonisms is the suppression of Cochliobolus sativus by Fusarium (roseum) species. Unfortunately, previous studies involved single isolates of each pathogen and thus, provided no indication of the spectrum of responses that occur across the respective species. To investigate the variability in interactions between Cochliobolus sativus and Fusarium pseudograminearum, field and greenhouse trials were conducted that included monitoring of spring wheat plant health and monitoring of pathogen populations via quantitative real-time polymerase chain reaction. The interactions between two isolates of C. sativus and four isolates of F. pseudograminearum were explored in three geographically distinct wheat fields. To complement field trials and to limit potentially confounding environmental variables that are often associated with field studies, greenhouse trials were performed that investigated the interactions among and between three isolates of C. sativus and four isolates of F. pseudograminearum. Across field locations, C. sativus isolate Cs2344 consistently and significantly reduced Fusarium populations by an average of 20.1%. Similarly, F. pseudograminearum isolate Fp2228 consistently and significantly reduced C. sativus field populations by an average of 30.9%. No interaction was detected in the field between pathogen species with regards to disease or crop losses. Greenhouse results confirmed a powerful (>99%), broadly effective suppression of Fusarium populations by isolate Cs2344. Among greenhouse trials, additional isolate–isolate interactions were observed affecting Fusarium populations. Due to lower C. sativus population sizes in greenhouse trials, significant Fusarium suppression of C. sativus was only detected in one isolate–isolate interaction. This study is the first to demonstrate suppression of Fusarium spp. by C. sativus in field and greenhouse settings. These findings also reveal a complex competitive interaction between these two pathogen species that was previously unknown.

scholarly journals Timing in a fluctuating environment: environmental variability and asymmetric fitness curves can lead to adaptively mismatched avian reproduction

2012 ◽  
Vol 279 (1741) ◽  
pp. 3161-3169 ◽  
Author(s):  
Marjolein E. Lof ◽  
Thomas E. Reed ◽  
John M. McNamara ◽  
Marcel E. Visser
Keyword(s):  
Temporal Variation ◽  
Environmental Variability ◽  
Environmental Variation ◽  
Reaction Norm ◽  
Optimal Timing ◽  
Variable Environment ◽  
Avian Reproduction ◽  
Breeding Date ◽  
Fitness Curve ◽  
Warming World

Adaptation in dynamic environments depends on the grain, magnitude and predictability of ecological fluctuations experienced within and across generations. Phenotypic plasticity is a well-studied mechanism in this regard, yet the potentially complex effects of stochastic environmental variation on optimal mean trait values are often overlooked. Using an optimality model inspired by timing of reproduction in great tits, we show that temporal variation affects not only optimal reaction norm slope, but also elevation. With increased environmental variation and an asymmetric relationship between fitness and breeding date, optimal timing shifts away from the side of the fitness curve with the steepest decline. In a relatively constant environment, the timing of the birds is matched with the seasonal food peak, but they become adaptively mismatched in environments with temporal variation in temperature whenever the fitness curve is asymmetric. Various processes affecting the survival of offspring and parents influence this asymmetry, which collectively determine the ‘safest’ strategy, i.e. whether females should breed before, on, or after the food peak in a variable environment. As climate change might affect the (co)variance of environmental variables as well as their averages, risk aversion may influence how species should shift their seasonal timing in a warming world.

scholarly journals Modeling and System Integration for a Thin Pneumatic Rubber 3-DOF Actuator

Actuators ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 32 ◽  
Author(s):  
Shuhei Kawamura ◽  
Mizuki Sudani ◽  
Mingcong Deng ◽  
Yuichi Noge ◽  
Shuichi Wakimoto
Keyword(s):  
System Integration ◽  
Degrees Of Freedom ◽  
Small Diameter ◽  
Experimental System ◽  
Longitudinal Direction ◽  
Axial Direction ◽  
Artificial Muscles ◽  
Contraction Force ◽  
Proposed Model ◽  
Soft Actuators

Recently, soft actuators have been getting increased attention within various fields. The actuators are composed of flexible materials and driven by pneumatic pressure. A thin pneumatic rubber actuator generating 3 degrees of freedom motion, called 3-DOF micro-hand, has small diameter McKibben artificial muscles which generate a contraction force in the axial direction. By this structure, the micro-hand contracts in the longitudinal direction and bends in any direction by changing the applied air pressure pattern to the artificial muscles. The input–output relation of the micro-hand, however, is complicated and has not been modeled. In this paper, modeling for 3-DOF micro-hand is proposed. Moreover, the experimental system is built for the micro-hand and the proposed model is evaluated by using the experimental results.

Response of Processing Peas(Pisum sativum)and Annual Weeds to Acetanilide Herbicides

Weed Science ◽  
1978 ◽  
Vol 26 (4) ◽  
pp. 313-317 ◽  
Author(s):  
G. L. Jordan ◽  
R. G. Harvey
Keyword(s):  
Pisum Sativum ◽  
Relative Effectiveness ◽  
Field Studies ◽  
Field Trials ◽  
Silica Sand ◽  
Simulated Rainfall ◽  
Annual Grass ◽  
Excellent Control ◽  
Glycine Ethyl Ester ◽  
Annual Weeds

The relative effectiveness of eight acetanilide herbicides for controlling annual weeds in processing peas(Pisum sativumL.) was evaluated in field studies and the susceptibility of peas to injury from these herbicides was studied in both the field and greenhouse. Alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] was the most phytotoxic to peas grown in washed silica sand in the greenhouse when the herbicides were applied at concentrations of 2 and 8 mg/L. Field trials conducted over a 2-yr period and simulated rainfall experiments in the greenhouse demonstrated that the phytotoxicity to peas by acetanilide herbicides applied preemergence at 2.2 and 4.5 kg/ha was greatly influenced by subsequent rainfall. When 2.5 cm of simulated rainfall were applied immediately after herbicide application, pea injury increased. Injury to peas was avoided in the field by delaying alachlor application at 2.2 kg/ha until peas began to emerge. This treatment also gave excellent control of annual grass weeds. Greenhouse studies demonstrated that injury to peas by all eight acetanilide herbicides at 2.2 and 4.5 kg/ha could be avoided by delaying application until pea emergence. Alachlor, propachlor (2-chloro-N-isopropylacetanilide), and metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] gave slightly superior weed control than butachlor [N-(butoxymethyl)diethylacetanilide] and H 22234 [N-chloroacetyl-N-(2,6-diethylphenyl)-glycine ethyl ester].

scholarly journals Non-Targeted Metabolomics Reveals Sorghum Rhizosphere-Associated Exudates are Influenced by the Belowground Interaction of Substrate and Sorghum Genotype

2019 ◽  
Vol 20 (2) ◽  
pp. 431 ◽  
Author(s):  
Sarah B. Miller ◽  
Adam L. Heuberger ◽  
Corey D. Broeckling ◽  
Courtney E. Jahn
Keyword(s):  
Plant Traits ◽  
Plant Root ◽  
Root Exudation ◽  
Metabolite Identification ◽  
Ultra Performance Liquid Chromatography ◽  
Gas Chromatography Mass Spectrometry ◽  
Targeted Metabolomics ◽  
Major Bottleneck ◽  
Sorghum Genotypes ◽  
Plant Process

Root exudation is an important plant process by which roots release small molecules into the rhizosphere that serve in overall plant functioning. Yet, there is a major gap in our knowledge in translating plant root exudation in artificial systems (i.e., hydroponics, sterile media) to crops, specifically for soils expected in field conditions. Sorghum (Sorghum bicolor L. Moench) root exudation was determined using both ultra-performance liquid chromatography and gas chromatography mass spectrometry-based non-targeted metabolomics to evaluate variation in exudate composition of two sorghum genotypes among three substrates (sand, clay, and soil). Above and belowground plant traits were measured to determine the interaction between sorghum genotype and belowground substrate. Plant growth and quantitative exudate composition were found to vary largely by substrate. Two types of changes to rhizosphere metabolites were observed: rhizosphere-enhanced metabolites (REMs) and rhizosphere-abated metabolites (RAMs). More REMs and RAMs were detected in sand and clay substrates compared to the soil substrate. This study demonstrates that belowground substrate influences the root exudate profile in sorghum, and that two sorghum genotypes exuded metabolites at different magnitudes. However, metabolite identification remains a major bottleneck in non-targeted metabolite profiling of the rhizosphere.

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