Scholarly Works, School of Plant and Environmental Sciences

Permanent URI for this collection

https://hdl.handle.net/10919/97229

Browse

Now showing 1 - 20 of 1099

A silent spring, or a new cacophony? Invasive plants as maestros of modern soundscapes
Barney, Jacob N.; O'Malley, Grace; Ripa, Gabrielle N.; Drake, Joseph; Franusich, David; Mims, Meryl C. (Wiley, 2024-04-01)
Sound plays a key role in ecosystem function and is a defining part of how humans experience nature. In the seminal book Silent Spring (Carson 1962), Rachel Carson warned of the ecological and environmental harm of pesticide usage by envisioning a future without birdsong. Soundscapes, or the acoustic patterns of a landscape through space and time, encompass both biological and physical processes (Pijanowski et al. 2011). Yet, they are often an underappreciated element of the natural world and the ways in which it is perceived. Scientists are only beginning to quantify changes to soundscapes, largely in response to anthropogenic sounds, but soundscape alteration is likely linked to many dimensions of global change. For example, invasive non-native species (hereafter, invasive species) are near-ubiquitous members of ecosystems globally and threaten both natural and managed ecosystems at great expense. Their impacts to soundscapes may be an important, yet largely unknown, threat to ecosystems and the human and economic systems they support.
Effect of organic biostimulants on cannabis productivity and soil microbial activity under outdoor conditions
Da Cunha Leme Filho, Jose F.; Chim, Bee K.; Bermand, Cameron; Diatta, Andre A.; Thomason, Wade E. (2024-03-26)
In 2019 and 2020, we investigated the individual and combined effects of two biofertilizers (manure tea and bioinoculant) and one humic acid (HA) product on cannabis biochemical and physiological parameters and soil CO2 evolution under outdoor conditions. Our hypothesis was that HA would increase the microbial activity in the biofertilizers and synergy of both compounds would promote better plant performance and stimulate soil microbial activity. In 2020, the individual and combined application of biofertilizers and HA increased cannabis height, chlorophyll content, photosynthetic efficiency, aboveground biomass, and bucked biomass by 105, 52, 43, 122, and 117%, respectively. Impacts were greater under suboptimal growing conditions caused by planting delay experienced in 2020. In 2019, planting date occurred in-between the most favorable period and chlorophyll content and photosynthetic efficiency were the only parameters influenced by the application of biostimulants. The discrepancies between the two growing seasons reinforce the evidence of other studies that biostimulants efficacy is maximized under stress conditions. This study could not conclusively confirm that the combined use of biofertilizer + HA is a superior practice since affected plant parameters did not differ from application of the compounds singly. Similarly, only one biofertilizer + HA treatment increased soil microbial activity. More research is needed to define optimum rates and combinations of biofertilizer and stimulants for cannabis.
Incidence of Per-And Polyfluoroalkyl Substances (PFAS) in Private Drinking Water Supplies in Southwest Virginia, USA
Hohweiler, Kathleen; Krometis, Leigh-Anne H.; Ling, Erin; Xia, Kang (2024)
Per- and polyfluoroalkyl substances (PFAS) are a class of man-made contaminants of increasing human health concern due to their resistance to degradation, widespread environmental occurrence, bioaccumulation in organ tissue, and potential negative health impacts. Private drinking water supplies may be uniquely vulnerable to PFAS contamination, as these systems are not subject to federal regulations and often include limited treatment prior to use. The goal of this study was to determine the incidence of PFAS contamination in private drinking water supplies in two counties in Southwest Virginia, USA (Floyd and Roanoke), and to examine the potential for reliance on citizen-science based strategies for sample collection in subsequent broader efforts. Samples for inorganic ions, bacteria, and PFAS analysis were collected on separate occasions by participants and experts at the home drinking water point of use (POU) for comparison. Experts also collected outside tap samples for PFAS analysis. At least one PFAS was detectable in 88% of POU samples collected (n=60), with an average total PFAS concentration of 23.5±30.8 ppt. PFOA and PFOS, two PFAS compounds which presently have EPA health advisories, were detectable in 13% and 22% of POU samples, respectively. Of the 31 compounds targeted, 15 were detectable in at least one sample. On average, each POU sample contained approximately 3.3 PFAS compounds, and one sample contained as many as 8 compounds, indicating that exposure to a mixture of PFAS in drinking water may be occurring. Although there were significant differences in total PFAS concentrations between expert and participant collected samples (Wilcoxon, alpha = 0.05), collector bias was inconsistent, and may be due to the time of day of sampling (i.e. morning, afternoon) or specific attributes of a given home. Future studies reliant on participant collection of samples appear possible given proper training, coordination, and instruction.
Pasture Biomass Estimation Using Ultra-High-Resolution RGB UAVs Images and Deep Learning
Vahidi, Milad; Shafian, Sanaz; Thomas, Summer; Maguire, Rory (MDPI, 2023-12-13)
The continuous assessment of grassland biomass during the growth season plays a vital role in making informed, location-specific management choices. The implementation of precision agriculture techniques can facilitate and enhance these decision-making processes. Nonetheless, precision agriculture depends on the availability of prompt and precise data pertaining to plant characteristics, necessitating both high spatial and temporal resolutions. Utilizing structural and spectral attributes extracted from low-cost sensors on unmanned aerial vehicles (UAVs) presents a promising non-invasive method to evaluate plant traits, including above-ground biomass and plant height. Therefore, the main objective was to develop an artificial neural network capable of estimating pasture biomass by using UAV RGB images and the canopy height models (CHM) during the growing season over three common types of paddocks: Rest, bale grazing, and sacrifice. Subsequently, this study first explored the variation of structural and color-related features derived from statistics of CHM and RGB image values under different levels of plant growth. Then, an ANN model was trained for accurate biomass volume estimation based on a rigorous assessment employing statistical criteria and ground observations. The model demonstrated a high level of precision, yielding a coefficient of determination (R²) of 0.94 and a root mean square error (RMSE) of 62 (g/m²). The evaluation underscores the critical role of ultra-high-resolution photogrammetric CHMs and red, green, and blue (RGB) values in capturing meaningful variations and enhancing the model’s accuracy across diverse paddock types, including bale grazing, rest, and sacrifice paddocks. Furthermore, the model’s sensitivity to areas with minimal or virtually absent biomass during the plant growth period is visually demonstrated in the generated maps. Notably, it effectively discerned low-biomass regions in bale grazing paddocks and areas with reduced biomass impact in sacrifice paddocks compared to other types. These findings highlight the model’s versatility in estimating biomass across a range of scenarios, making it well suited for deployment across various paddock types and environmental conditions.
Quantitative texture analysis comparison of three legumes
Miller, Rebekah; Duncan, Susan; Yin, Yun; Zhang, Bo; Lahne, Jacob (Frontiers, 2023-06-19)
A validated texture-analysis method to evaluate product quality in frozen or cooked legumes is needed to support high-quality vegetable production but is not currently established in the literature. Peas, lima beans, and edamame were investigated in this study due to similar market use as well as growth in plant-based protein consumption in the United States. These three legumes were evaluated after three different processing treatments (blanch/freeze/thaw (BFT); BFT+microwave heat (BFT+M); BF+stove-top cooking (BF+C)), using both compression and puncture analysis following an American Society of Agricultural and Biological Engineers (ASABE) texture analysis method and moisture testing following an American Society for Testing and Materials (ASTM) standard method. Texture analysis results showed differences between legumes and processing methods. Compression analysis identified more differences between treatments within product type than puncture for both edamame and lima beans indicating compression might be more sensitive to texture changes in these products. Implementation of a standard texture method for legume vegetables for growers and producers would provide a consistent quality check to support efficient production of high-quality legumes. Due to the sensitivity obtained from the compression texture method in this work, compression should be considered for future research into a robust method to evaluate edamame and lima bean textures throughout the growing and production processes.
Suggestions for Promotion and Tenure Documents
Galbraith, John; Stewart, Ryan D. (2022-05-10)
Nematode Tradings Cards Set Six
Eisenback, Jonathan (Society of Nematologists Education Committee, 2023-07-17)
Nematode Trading Cards Deck Six is a collection of 54 full color cards from six categories including 1)Behavior, 2)Control, 3)Habitats, 4)Morphology, 5) Nematodes, and 6)Nematologists. This deck was given to all of the participants in the 62nd Annual Meeting of the Society of Nematologists in Columbus, Ohio in 2023. They serve as the source material for the game played by teams of graduate students at the annual meeting call "The Cobb Bowl - Nematodes in Jeopardy".
A suberized exodermis is required for tomato drought tolerance
Cantó-Pastor, A.; Kajala, K.; Shaar-Moshe, L.; Manzano, C.; Timilsena, P.; De Bellis, D.; Gray, S.; Holbein, J.; Yang, H.; Mohammad, S.; Nirmal, N.; Suresh, K.; Ursache, R.; Mason, G. A.; Gouran, M.; West, D. A.; Borowsky, A. T.; Shackel, K. A.; Sinha, N.; Bailey-Serres, J.; Geldner, N.; Li, Song; Franke, R. B.; Brady, S. M. (Springer, 2024-01-02)
Plant roots integrate environmental signals with development using exquisite spatiotemporal control. This is apparent in the deposition of suberin, an apoplastic diffusion barrier, which regulates flow of water, solutes and gases, and is environmentally plastic. Suberin is considered a hallmark of endodermal differentiation but is absent in the tomato endodermis. Instead, suberin is present in the exodermis, a cell type that is absent in the model organism Arabidopsis thaliana. Here we demonstrate that the suberin regulatory network has the same parts driving suberin production in the tomato exodermis and the Arabidopsis endodermis. Despite this co-option of network components, the network has undergone rewiring to drive distinct spatial expression and with distinct contributions of specific genes. Functional genetic analyses of the tomato MYB92 transcription factor and ASFT enzyme demonstrate the importance of exodermal suberin for a plant water-deficit response and that the exodermal barrier serves an equivalent function to that of the endodermis and can act in its place.
Diversity and ice nucleation activity of Pseudomonas syringae in drone water samples from eight lakes in Austria
Hanlon, Regina; Jimenez-Sanchez, Celia; Benson, James; Aho, Ken; Morris, Cindy; Seifried, Teresa; Bolah, Philipp; Grothe, Hinrich; Schmale, David G. III (PeerJ, 2023-11-28)
Bacteria from the Pseudomonas syringae complex (comprised of at least 15 recognized species and more than 60 different pathovars of P. syringae sensu stricto) have been cultured from clouds, rain, snow, streams, rivers, and lakes. Some strains of P. syringae express an ice nucleation protein (hereafter referred to as ice+) that catalyzes the heterogeneous freezing of water. Though P. syringae has been sampled intensively from freshwater sources in the U.S. and France, little is known about the genetic diversity and ice nucleation activity of P. syringae in other parts of the world. We investigated the haplotype diversity and ice nucleation activity at −8 ◦C (ice+) of strains of P. syringae from water samples collected with drones in eight freshwater lakes in Austria. A phylogenetic analysis of citrate synthase (cts) sequences from 271 strains of bacteria isolated from a semi-selective medium for Pseudomonas revealed that 69% (188/271) belonged to the P. syringae complex and represented 32 haplotypes in phylogroups 1, 2, 7, 9, 10, 13, 14 and 15. Strains within the P. syringae complex were identified in all eight lakes, and seven lakes contained ice+ strains. Partial 16S rDNA sequences were analyzed from a total of 492 pure cultures of bacteria isolated from non-selective medium. Nearly half (43.5%; 214/492) were associated with the genus Pseudomonas. Five of the lakes (ALT, GRU, GOS, GOL, and WOR) were all distinguished by high levels of Pseudomanas (p ≤ 0.001). HIN, the highest elevation lake, had the highest percentage of ice+ strains. Our work highlights the potential for uncovering new haplotypes of P. syringae in aquatic habitats, and the use of robotic technologies to sample and characterize microbial life in remote settings.
Genomic delineation and description of species and within-species lineages in the genus Pantoea
Crosby, Katherine C.; Rojas, Mariah; Sharma, Parul; Johnson, Marcela A.; Mazloom, Reza; Kvitko, Brian H.; Smits, Theo HM M.; Venter, Stephanus N.; Coutinho, Teresa A.; Heath, Lenwood S.; Palmer, Marike; Vinatzer, Boris A. (Frontiers, 2023-11-09)
As the name of the genus Pantoea (“of all sorts and sources”) suggests, this genus includes bacteria with a wide range of provenances, including plants, animals, soils, components of the water cycle, and humans. Some members of the genus are pathogenic to plants, and some are suspected to be opportunistic human pathogens; while others are used as microbial pesticides or show promise in biotechnological applications. During its taxonomic history, the genus and its species have seen many revisions. However, evolutionary and comparative genomics studies have started to provide a solid foundation for a more stable taxonomy. To move further toward this goal, we have built a 2,509-gene core genome tree of 437 public genome sequences representing the currently known diversity of the genus Pantoea. Clades were evaluated for being evolutionarily and ecologically significant by determining bootstrap support, gene content differences, and recent recombination events. These results were then integrated with genome metadata, published literature, descriptions of named species with standing in nomenclature, and circumscriptions of yet-unnamed species clusters, 15 of which we assigned names under the nascent SeqCode. Finally, genome-based circumscriptions and descriptions of each species and each significant genetic lineage within species were uploaded to the LINbase Web server so that newly sequenced genomes of isolates belonging to any of these groups could be precisely and accurately identified.
Photosynthetic Rate and Root Growth Responses to Ascophyllum nodosum Extract–based Biostimulant in Creeping Bentgrass under Heat and Drought Stress
Zhang, Xunzhong; Taylor, Zachary; Goatley, Mike; Wang, Kehua; Brown, Isabel; Kosiarski, Kelly (American Society for Horticultural Science, 2023-08-01)
Creeping bentgrass (Agrostis stolonifera) experiences quality decline during summer in the United States transition zone and warmer regions. Various bioproducts have been used to improve creeping bentgrass performance and to mitigate effects of summer stress in the United States transition zone. This 2-year study was carried out to examine if foliar application of seaweed extract (SWE; Ascophyllum nodosum)-based biostimulant UtilizeVR could enhance creeping bentgrass nitrate reductase (NaR) activity, and root viability under heat and drought stress conditions. The UtilizeVR was sprayed biweekly on creeping bentgrass foliage at 0, 29, 58, 87, and 116 mL.m22, with application volume of 815 L.ha22. Two weeks after first application, plants were exposed to heat (35/25◦C, day/night) and drought stress (40% to 50% evapotranspiration replacement) conditions for 42 days in an environment-controlled growth chamber. In general, the abiotic stress caused turf quality reduction. Foliar application of UtilizeVR at 58, 87, and 116 mL.m22 increased turf quality, leaf color ratings, leaf chlorophyll, carotenoid content, and net photosynthetic rate (Pn). UtilizeVR at 58, 87, and 116 mL.m22 increased NaR activity by 26.5%, 16.3%, and 16.3%, respectively, when compared with the control. UtilizeVR at 58, 87, and 116 mL.m22 increased root biomass, root length, surface area (SA), and root volume when compared with the control. UtilizeVR at 58 and 87 mL.m22 improved root viability by 16.3% and 30.9%, respectively, when compared with the control. Our data indicate that the SWE-based biostimulant UtilizeVR improves nitrogen (N) metabolism and root viability. UtilizeVR treatment at 58 mL.m22 biweekly can be considered an effective approach for improving creeping bentgrass performance during summer stress.
Adaptive constraints at the range edge of a widespread and expanding invasive plant
Fletcher, Rebecca A.; Atwater, Daniel Z.; Haak, David C.; Bagavathiannan, Muthukumar; DiTommaso, Antonio; Lehnhoff, Erik; Paterson, Andrew H.; Auckland, Susan; Govindasamy, Prabhu; Lemke, Cornelia; Morris, Edward; Rainville, Lisa; Barney, Jacob N. (Oxford University Press, 2023-11-05)
Identifying the factors that facilitate and limit invasive species' range expansion has both practical and theoretical importance, especially at the range edges. Here, we used reciprocal common garden experiments spanning the North/South and East/West range that include the North American core, intermediate and range edges of the globally invasive plant, Johnsongrass (Sorghum halepense) to investigate the interplay of climate, biotic interactions (i.e. competition) and patterns of adaptation. Our results suggest that the rapid range expansion of Johnsongrass into diverse environments across wide geographies occurred largely without local adaptation, but that further range expansion may be restricted by a fitness trade-off that limits population growth at the range edge. Interestingly, plant competition strongly dampened Johnsongrass growth but did not change the rank order performance of populations within a garden, though this varied among gardens (climates). Our findings highlight the importance of including the range edge when studying the range dynamics of invasive species, especially as we try to understand how invasive species will respond to accelerating global changes.
Soil properties affect crop yield changes under conservation agriculture: A systematic analysis
Ren, Xiaohua; Zou, Wenjing; Jiao, Juying; Stewart, Ryan D.; Jian, Jinshi (Wiley, 2023-09-13)
Conservation agriculture (CA) has the potential to sustain soil productivity and benefit agroecosystems, yet it is not fully understood how yield responses of different cropping systems are affected by inherent soil characteristics, for example, texture and dynamic soil properties, such as aggregation, nutrients and erosion. In this study, we conducted a systematic review to compare crop yield from cropland with conventional management versus different CA practices, specifically reduced- or no-tillage, agroforestry, organic farming and cover crops. The data were first analysed for different climatic regions, soil textures and cash crop types. We then quantified how yield responses correlated with soil properties change under different CA practices. The results showed that CA practices were associated with an overall mean crop yield increase of 12%. This response was primarily driven by corn, which had a mean yield increase of almost 41% after CA implementation, whereas other cash crops did not have significant yield responses or showed slight decreases, as rotation with mixtures of multiple cash crops had a mean decrease of 6% when using CA. The increase in corn yield after CA may be related to the enhanced ability of that crop to absorb nutrient elements (e.g. nitrogen) and reduce nutrient leaching. Agroforestry increased crop yield by 66% and cover cropping increased yield by 11%, likely due to increases in soil water content and nutrient availability and decreases in erosion and surface runoff. However, other agricultural systems showed no significant increase after CA compared with conventional row cropping practices. Using CA practices had the greatest yield benefit in tropical climates and when farming in coarse-textured soils. In addition, legumes and grass-legume mixtures resulted in significant cash crop yield increases, possibly because legumes promoted the increase of soil nitrogen and depleted soil moisture less compared with other cover crops. The results provide new insight into how interactions between soil properties and CA practices affect crop yield and at the same time can help guide the development of practical, evidence-based guidelines for using conservation practices to improve yield in corn and other cash crops.
Life Cycle of the Root-knot Nematodes with Narration
Eisenback, Jonathan D. (2023-10-12)
Life Cycle of the Root-knot Nematodes with Narration
Life Cycle of the root-knot nematode (3rd printing)
Eisenback, Jonathan D. (Society of Nematologists Education Committee, 2023-06-30)
Educational poster.
Cellular insights of beech leaf disease reveal abnormal ectopic cell division of symptomatic interveinal leaf areas
Vieira, Paulo; Kantor, Mihail R.; Jansen, Andrew; Handoo, Zafar A.; Eisenback, Jonathan D. (Public Library of Science, 2023-10-05)
The beech leaf disease nematode, Litylenchus crenatae subsp. mccannii, is recognized as a newly emergent nematode species that causes beech leaf disease (BLD) in beech trees (Fagus spp.) in North America. Changes of leaf morphology before emergence from the bud induced by BLD can provoke dramatic effects on the leaf architecture and consequently to tree performance and development. The initial symptoms of BLD appear as dark green, interveinal banding patterns of the leaf. Despite the fast progression of this disease, the cellular mechanisms leading to the formation of such aberrant leaf phenotype remains totally unknown. To understand the cellular basis of BLD, we employed several types of microscopy to provide an exhaustive characterization of nematode-infected buds and leaves. Histological sections revealed a dramatic cell change composition of these nematode-infected tissues. Diseased bud scale cells were typically hypertrophied and showed a high variability of size. Moreover, while altered cell division had no influence on leaf organogenesis, induction of cell proliferation on young leaf primordia led to a dramatic change in cell layer architecture. Hyperplasia and hypertrophy of the different leaf cell layers, coupled with an abnormal proliferation of chloroplasts especially in the mesophyll cell layers, resulted in the typical interveinal leaf banding. These discrepancies in leaf cell structure were depicted by an abnormal rate of cellular division of the leaf interveinal areas infected by the nematode, promoting significant increase of cell size and leaf thickness. The formation of symptomatic BLD leaves is therefore orchestrated by distinct cellular processes, to enhance the value of these feeding sites and to improve their nutrition status for the nematode. Our findings thus uncover relevant cellular events and provide a structural framework to understand this important disease.
Cover crop termination options and application of remote sensing for evaluating termination efficiency
Kumar, Vipin; Singh, Vijay; Flessner, Michael L.; Haymaker, Joseph; Reiter, Mark S.; Mirsky, Steven B. (Public Library of Science, 2023-04-20)
Efficient termination of cover crops is an important component of cover crop management. Information on termination efficiency can help in devising management plans but estimating herbicide efficacy is a tedious task and potential remote sensing technologies and vegetative indices (VIs) have not been explored for this purpose. This study was designed to evaluate potential herbicide options for the termination of wheat (Triticum aestivum L.), cereal rye (Secale cereale L.), hairy vetch (Vicia villosa Roth.), and rapeseed (Brassica napus L.), and to correlate different VIs with visible termination efficiency. Nine herbicides and one roller-crimping treatment were applied to each cover crop. Among different herbicides used, glyphosate, glyphosate + glufosinate, paraquat, and paraquat + metribuzin provided more than 95% termination for both wheat and cereal rye 28 days after treatment (DAT). For hairy vetch, 2,4-D + glufosinate and glyphosate + glufosinate, resulted in 99 and 98% termination efficiency, respectively, followed by 2,4-D + glyphosate and paraquat with 92% termination efficiency 28 DAT. No herbicide provided more than 90% termination of rapeseed and highest control was provided by paraquat (86%), 2,4-D + glufosinate (85%), and 2,4-D + glyphosate (85%). Roller-crimping (without herbicide application) did not provide effective termination of any cover crop with 41, 61, 49, and 43% termination for wheat, cereal rye, hairy vetch, and rapeseed, respectively. Among the VIs, Green Leaf Index had the highest Pearson correlation coefficient for wheat (r = -0.786, p = <0.0001) and cereal rye (r = -0.804, p = <0.0001) with visible termination efficiency rating. Whereas for rapeseed, the Normalized Difference Vegetation Index (NDVI) had the highest correlation coefficient (r = -0.655, p = <0.0001). The study highlighted the need for tankmixing 2,4-D or glufosinate with glyphosate for termination instead of blanket application of glyphosate alone for all crops including rapeseed and other broadleaf cover crops.
ARGem: a new metagenomics pipeline for antibiotic resistance genes: metadata, analysis, and visualization
Liang, Xiao; Zhang, Jingyi; Kim, Yoonjin; Ho, Josh; Liu, Kevin; Keenum, Ishi M.; Gupta, Suraj; Davis, Benjamin; Hepp, Shannon L.; Zhang, Liqing; Xia, Kang; Knowlton, Katharine F.; Liao, Jingqiu; Vikesland, Peter J.; Pruden, Amy; Heath, Lenwood S. (Frontiers, 2023-09-15)
Antibiotic resistance is of crucial interest to both human and animal medicine. It has been recognized that increased environmental monitoring of antibiotic resistance is needed. Metagenomic DNA sequencing is becoming an attractive method to profile antibiotic resistance genes (ARGs), including a special focus on pathogens. A number of computational pipelines are available and under development to support environmental ARG monitoring; the pipeline we present here is promising for general adoption for the purpose of harmonized global monitoring. Specifically, ARGem is a user-friendly pipeline that provides full-service analysis, from the initial DNA short reads to the final visualization of results. The capture of extensive metadata is also facilitated to support comparability across projects and broader monitoring goals. The ARGem pipeline offers efficient analysis of a modest number of samples along with affordable computational components, though the throughput could be increased through cloud resources, based on the user’s configuration. The pipeline components were carefully assessed and selected to satisfy tradeoffs, balancing efficiency and flexibility. It was essential to provide a step to perform short read assembly in a reasonable time frame to ensure accurate annotation of identified ARGs. Comprehensive ARG and mobile genetic element databases are included in ARGem for annotation support. ARGem further includes an expandable set of analysis tools that include statistical and network analysis and supports various useful visualization techniques, including Cytoscape visualization of co-occurrence and correlation networks. The performance and flexibility of the ARGem pipeline is demonstrated with analysis of aquatic metagenomes. The pipeline is freely available at https://github.com/xlxlxlx/ARGem.
Sustainable Production of Tomato Using Fish Effluents Improved Plant Growth, Yield Components, and Yield in Northern Senegal
Diatta, Andre A.; Manga, Anicet G. B.; Bassène, César; Mbow, Cheikh; Battaglia, Martin; Sambou, Mariama; Babur, Emre; Uslu, Ömer Süha (MDPI, 2023-10-26)
Aquaculture and agriculture integration is essential for maximizing water and land productivity in arid and semi-arid regions. Thus, the increase in global water scarcity and the dual use of water for crop and fish production has the potential to optimize water use, dispose of aquaculture wastes, provide additional nutrients to crops, and reduce inorganic fertilizer usage, thus maximizing farm productivity. This greenhouse study was conducted to determine the effects of fish effluents on the growth, yield parameters, and yield of tomatoes (Solanum lycopersicum L.). The experiment was carried out in a randomized complete block design with six replications. The 13 treatments consisted of three irrigation water types (river water—control, Nile tilapia—Oreochromis niloticus, African sharptooth catfish—Clarias gariepinus), four fertilizers (chicken manure, cow manure, sheep manure; recommended rate of NPK—280 kg ha⁻¹ of 10-10-20), and six mixed treatments with fish effluent and 50% of the applied rate of manure alone. Results showed that irrigation with C. gariepinus effluent increased the stem diameter by 21%, the number of flowers by 88%, the fruit number by 50%, the fruit diameter by 24%, the mean fruit weight by 34%, and total fruit weight of tomato by 96% compared to NPK treatments. These effects were more evident when C. gariepinus was mixed with poultry, cow, and sheep manures, which resulted in significantly greater values than recommended rates of NPK. The higher productivity observed from the combined use of C. gariepinus and manure treatments (133% increase, on average) compared to NPK treatments was related to the continuous supply of nutrients and the increase of yield parameters. Therefore, the combined use of C. gariepinus effluent and manure can be a viable alternative for smallholder farmers, for whom inorganic fertilizers are often neither affordable nor available.
Estimation of Bale Grazing and Sacrificed Pasture Biomass through the Integration of Sentinel Satellite Images and Machine Learning Techniques
Vahidi, Milad; Shafian, Sanaz; Thomas, Summer; Maguire, Rory (MDPI, 2023-10-18)
Quantifying the forage biomass in pastoral systems can be used for enhancing farmers’ decision-making in precision management and optimizing livestock feeding systems. In this study, we assessed the feasibility of integrating Sentinel-1 and Sentinel-2 satellite imagery with machine learning techniques to estimate the aboveground biomass and forage quality of bale grazing and sacrificed grassland areas in Virginia. The workflow comprised two steps, each addressing specific objectives. Firstly, we analyzed the temporal variation in spectral and synthetic aperture radar (SAR) variables derived from Sentinel-1 and Sentinel-2 time series images. Subsequently, we evaluated the contribution of these variables with the estimation of grassland biomass using three machine learning algorithms, as follows: support vector regression (SVR), random forest (RF), and artificial neural network (ANN). The quantitative assessment of the models demonstrates that the ANN algorithm outperforms the other approaches when estimating pasture biomass. The developed ANN model achieved an R² of 0.83 and RMSE of 6.68 kg/100 sq. meter. The evaluation of feature importance revealed that VV and VH polarizations play a significant role in the model, indicating the SAR sensor’s ability to perceive changes in plant structure during the growth period. Additionally, the blue, green, and NIR bands were identified as the most influential spectral variables in the model, underscoring the alterations in the spectrum of the pasture over time.

Browse

Recent Submissions