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Volume 12, January

Agronomy, Volume 12, Issue 2 (February 2022) – 313 articles

Cover Story (view full-size image): Society seeks to reduce the labour needed in food production. Tomato is the second most harvested vegetable worldwide, and a large fraction of labour costs in greenhouse production is absorbed by the harvesting operation. Being a recurrent task, it becomes an excellent candidate for automation. The development of an accurate fruit detection system is a crucial step to achieve a fully automated robotic harvest. In this study, deep learning models were used for the detection of greenhouse tomatoes and compared with a conventional method based on the HSV colour space for classification based on ripeness.  The results obtained by both approaches highlight their potential use in fruit detection and classification. View this paper.
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Article
The Role of Soil Moisture Information in Developing Robust Climate Services for Smallholder Farmers: Evidence from Ghana
Agronomy 2022, 12(2), 541; https://doi.org/10.3390/agronomy12020541 - 21 Feb 2022
Viewed by 644
Abstract
In Ghana, most of the farmers are engaged in small-scale rainfed farming where the success is influenced by the prevailing weather conditions. Current Climate Information Services (CISs) only provide information on rainfall conditions to reduce their farming vulnerability to climate extremes. Access to [...] Read more.
In Ghana, most of the farmers are engaged in small-scale rainfed farming where the success is influenced by the prevailing weather conditions. Current Climate Information Services (CISs) only provide information on rainfall conditions to reduce their farming vulnerability to climate extremes. Access to other practical knowledge, such as soil moisture content would benefit farmers further in the decision-making process. This study aims to assess the role of soil moisture information in farmers’ agricultural decision-making and to understand how this information is being perceived, assessed, and applied. Exploratory research, combined with field visits and farmer interviews, was carried out in Gbulung, Napakzoo, and Yapalsi communities in the outskirts of Tamale, northern Ghana in October–December 2021. Results show that soil moisture information is highly important for activities, such as fertilizer application and sowing. Soil moisture information, however, is not readily available to the farmers, causing them to rely solely on their indigenous knowledge to monitor the soil moisture conditions. Our study reveals that developing a CIS embedded with soil moisture advisory module (CIS-SM) will help farmers in conducting strategic and tactical decision-making in their daily farming activities. Full article
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Article
Effects of Tray-Drying on the Physicochemical, Microbiological, Proximate, and Sensory Properties of White- and Red-Fleshed Loquat (Eriobotrya Japonica Lindl.) Fruit
Agronomy 2022, 12(2), 540; https://doi.org/10.3390/agronomy12020540 - 21 Feb 2022
Viewed by 490
Abstract
Loquat fruits, highly valued by consumers for their characteristic aroma and pleasant taste, have a short post-harvest life and are susceptible to mechanical damage, loss of firmness, and initial organoleptic characteristics. The aim of this work was to develop a drying method suitable [...] Read more.
Loquat fruits, highly valued by consumers for their characteristic aroma and pleasant taste, have a short post-harvest life and are susceptible to mechanical damage, loss of firmness, and initial organoleptic characteristics. The aim of this work was to develop a drying method suitable for storing loquat fruits in polyamide/polyethylene (PA/PE) bags containing two gaseous mixtures (treatments): MAPN2 (100% N2) and MAPP (21% O2 and 0.04% CO2), at room temperature (20 ± 1 °C) for at least 2 months. The effects of these conditions on the physico-chemical, microbiological, proximate, and sensory properties of fruit stored over a 50-day time interval were studied. The results showed that convective tray dehydration treatment at 70° for 12 h had good drying efficiency for loquat slices. In addition, the MAPN2 packaging limited the browning of the slices, keeping the microbial groups below the detection limits, with a clear positive effect on some minerals and vitamins, which were higher in concentration compared to the MAPP-packed samples. From an applicative point of view, the tray drying method for loquat fruits is useful on a small scale but could also be easily industrialized. Full article
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Article
Acclimatization of In Vitro Banana Seedlings Using Root-Applied Bio-Nanofertilizer of Copper and Selenium
Agronomy 2022, 12(2), 539; https://doi.org/10.3390/agronomy12020539 - 21 Feb 2022
Cited by 1 | Viewed by 417
Abstract
The production of in vitro banana transplants has become an important practice in the global banana production. Proper and enough nutrients are needed for banana production particularly during the acclimatization period. To avoid the environmental problem resulting from the chemical fertilizers, nanofertilizers of [...] Read more.
The production of in vitro banana transplants has become an important practice in the global banana production. Proper and enough nutrients are needed for banana production particularly during the acclimatization period. To avoid the environmental problem resulting from the chemical fertilizers, nanofertilizers of Se and Cu were separately applied during the acclimatization of banana. The biological form of nano-Cu (50 and 100 mg L−1) and nano-Se (25, 50, 75, and 100 mg L−1) were studied on acclimatized banana transplants under greenhouse conditions. Both applied nanofertilizers enhanced the growth of transplant by 10.9 and 12.6% for dry weight after nano-Se and nano-Cu application up to 100 mg L−1, respectively. The survival rate was also increased by increasing applied doses of both nanofertilizers up to 100 mg L−1, whereas the highest survival rate (95.3%) was recorded for nano-Cu. All studied photosynthetic pigments and its fluorescence were improved by applying nanofertilizers. Studied antioxidant enzymatic activities (CAT, PPO, and POX) were also increased. A pH decrease in the growing medium was noticed after applying nano-Cu, which may explain the high bioavailability of studied nutrients (N, P, K, Cu, Fe, Se, and Zn) by banana transplants. Full article
(This article belongs to the Special Issue The Role of Plant Biostimulants in Stressful Agriculture)
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Communication
Monitoring and Inference of Behavioral Resistance in Beneficial Insects to Insecticides in Two Pest Control Systems: IPM and Organic
Agronomy 2022, 12(2), 538; https://doi.org/10.3390/agronomy12020538 - 21 Feb 2022
Viewed by 392
Abstract
Pyrethrins are the most widely used insecticide class in olive groves with organic management. Although there are data sets about insect pests of stored products and human parasites developing resistance to pyrethrins, there is no information on the long-term effect on olive agroecosystems. [...] Read more.
Pyrethrins are the most widely used insecticide class in olive groves with organic management. Although there are data sets about insect pests of stored products and human parasites developing resistance to pyrethrins, there is no information on the long-term effect on olive agroecosystems. A field method based on the experimental induction of sublethal effects by means of insecticide application, and the monitoring of the response of insects through post-treatment sampling, has recently been developed. This method has allowed for the detection of populations behaviorally resistant to organophosphates in integrated pest management (IPM) and conventional crops. With the application of a similar methodology, this study aimed to verify the possible reaction of natural enemies in organic crops, using pyrethrins as an inducing insecticide. The study was carried out in 2019 in two olive groves in southern Spain (Jaén, Andalusia), one of them being IPM and the other being an organic production system. The results did not allow for verification of the behavioral resistance in populations of natural enemies of both IPM and organic management against pyrethrins, while against dimethoate, behavioral resistance was verified in IPM management. The possible causes involved in obtaining these results are discussed. Full article
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Article
Assessing Soil Organic Carbon, Soil Nutrients and Soil Erodibility under Terraced Paddy Fields and Upland Rice in Northern Thailand
Agronomy 2022, 12(2), 537; https://doi.org/10.3390/agronomy12020537 - 21 Feb 2022
Viewed by 466
Abstract
Terracing is the oldest technique for water and soil conservation on natural hilly slopes. In Northern Thailand, terraced paddy fields were constructed long ago, but scientific questions remain on how terraced paddy fields and upland rice (non-terraced) differ for soil organic carbon (SOC) [...] Read more.
Terracing is the oldest technique for water and soil conservation on natural hilly slopes. In Northern Thailand, terraced paddy fields were constructed long ago, but scientific questions remain on how terraced paddy fields and upland rice (non-terraced) differ for soil organic carbon (SOC) stocks, soil nutrients and soil erodibility. Therefore, this study aims to evaluate and compare SOC stocks, soil nutrients and soil erodibility between terraced paddy fields and upland rice at Ban Pa Bong Piang, Chiang Mai Province, Thailand. Topsoil (0–10 cm) was collected from terraced paddies and upland rice fields after harvest. Results showed that SOC stocks were 21.84 and 21.61 Mg·C·ha−1 in terraced paddy and upland rice fields, respectively. There was no significant difference in soil erodibility between terraced paddies (range 0.2261–0.2893 t·h·MJ−1·mm−1) and upland rice (range 0.2238–0.2681 t·h·MJ−1·mm−1). Most soil nutrients (NH4-N, NO3-N, available K, available Ca and available Mg) in the terraced paddy field were lower than those in the upland rice field. It was hypothesized that the continuous water flows from plot-to-plot until lowermost plot caused dissolved nutrients to be washed and removed from the flat surface, leading to a short period for accumulating nutrients into the soil. An increase in soil erodibility was associated with decreasing SOC stock at lower toposequence points. This study suggested that increasing SOC stock is the best strategy to minimize soil erodibility of both cropping systems, while proper water management is crucial for maintaining soil nutrients in the terraced paddy field. Full article
(This article belongs to the Special Issue Resilience in Soils and Land Use)
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Article
Organic Matter in Riverbank Sediments and Fluvisols from the Flood Zones of Lower Vistula River
Agronomy 2022, 12(2), 536; https://doi.org/10.3390/agronomy12020536 - 21 Feb 2022
Viewed by 369
Abstract
The research objective of this study was to determine whether and to what extent the form of use of Fluvisols (arable soil and grassland) of a Lower Vistula floodplain valley (Fordonska Valley, Poland) determined their relative organic matter properties, as compared with nearby [...] Read more.
The research objective of this study was to determine whether and to what extent the form of use of Fluvisols (arable soil and grassland) of a Lower Vistula floodplain valley (Fordonska Valley, Poland) determined their relative organic matter properties, as compared with nearby riverbank sediments. Riverbank sediments were sampled from a depth of 0–20 cm, and soil samples from 0 to30 cm, all in three replicates. Basic physico-chemical soil properties were determined: texture, pH, and the contents of total organic carbon (TOC), total nitrogen (TN), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). Humic acids (HAs) were extracted by the Schnitzer method and analysed to assess their spectrometric parameters in the UV–VIS range and hydrophilic and hydrophobic properties. Riverbank sediment samples contained significantly lower TOC and TN contents than Fluvisols, regardless of land-use type. The TOC, TN, DOC and DON contents and properties of humic acids in the Fluvisol surface layer depended on land-use type, because the arable soils had significantly lower TOC, TN, DOC and DON contents than the grasslands, despite having a similar grain size (texture). Based on the A2/4, A2/6, A4/6 ratios, it was found that HA molecules isolated from the humus horizon of arable soils had a higher degree of maturity than HAs isolated from grassland soil samples. The spectrometric properties of humic acids isolated from riverbank sediments showed a higher degree of maturity than those from Fluvisols. This research showed that the properties of humic acids in Fluvisols are determined by the quantity and quality of organic matter transported in suspended matter that accumulates annually in flood valleys during flood events. The current land-use type of Fluvisols significantly influenced the properties of organic matter, and thus of humic acids. Therefore, these properties can be used to evaluate the transformation of organic matter that occurs in Fluvisols depending on the type of use. Full article
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Article
Utilisation of Oil Palm’s Empty Fruit Bunch Spikelets for Oil-Spill Removal
Agronomy 2022, 12(2), 535; https://doi.org/10.3390/agronomy12020535 - 21 Feb 2022
Viewed by 497
Abstract
Agricultural sorbents have received attention for their effectiveness in oil removal. In Malaysia, oil palm’s empty fruit bunch (EFB) spikelets are an abundant agricultural waste that provides a non-toxic, renewable resource of cellulosic materials. In this study, the effectiveness of EFB spikelets to [...] Read more.
Agricultural sorbents have received attention for their effectiveness in oil removal. In Malaysia, oil palm’s empty fruit bunch (EFB) spikelets are an abundant agricultural waste that provides a non-toxic, renewable resource of cellulosic materials. In this study, the effectiveness of EFB spikelets to remove oil spills from seawater pollution in a filter system was investigated and the best optimisation approach for filtering conditions was determined. Experiments for oil spill clean-up were performed using a filter-based oil sorption system with a series of conditions such as temperature, time, packing density, and oil concentration to evaluate sorption capacity, oil and water absorbed efficiency. Fourier transform infrared spectroscopy (FTIR) was used to characterise the physicochemical properties of untreated and treated EFB fibres. Based on one-factor-at -a-time (OFAT) analysis conducted at 160 °C for 30 min on 0.1 g/cm3 of packing density containing 25% diesel, 8.667 mL of oil and 5 mL of water was absorbed. In response surface methodology (RSM), the three parameters of temperature, packing density and diesel concentration were observed as significant. From RSM fitting model analysis, the predicted value obtained for both oil and water absorbed were 8.805 and 5.213 mL, respectively. The experimental RSM values of 9 and 5 mL of oil and water absorbed were obtained. The result demonstrated the validity of the model as the experimental RSM values were close to the RSM model’s prediction. As compared to OFAT, the RSM method is more efficient in oil removal. This research contributes to a better knowledge of the usage of a natural sorbent as a method of diesel pollution remediation. Full article
(This article belongs to the Special Issue Innovative Approaches in Agricultural Waste Management)
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Article
Effect of Clay Mineralogy and Soil Organic Carbon in Aggregates under Straw Incorporation
Agronomy 2022, 12(2), 534; https://doi.org/10.3390/agronomy12020534 - 21 Feb 2022
Viewed by 467
Abstract
The interaction between soil organic carbon (SOC) and clay minerals is a critical mechanism for retaining SOC and protecting soil fertility and long-term agricultural sustainability. The SOC composition and minerals speciation in clay fractions (<2 μm) within soil aggregates under straw removed (T) [...] Read more.
The interaction between soil organic carbon (SOC) and clay minerals is a critical mechanism for retaining SOC and protecting soil fertility and long-term agricultural sustainability. The SOC composition and minerals speciation in clay fractions (<2 μm) within soil aggregates under straw removed (T) and straw incorporation (TS) conditions were analyzed by X-ray diffraction, Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The TS treatment promoted enrichment of clay in aggregates. The TS increased the contents of SOC (27.0–86.6%), poorly crystalline Fe oxide (Feo), and activity of Fe oxides (Feo/Fed); whereas, it reduced the concentrations of free Fe oxide (Fed) in the clay fractions within aggregates. Straw incorporation promoted the accumulation of aromatic-C and carboxylic-C in the clay fraction within aggregates. The relative amount of hydroxy-interlayered vermiculite, aliphatic-C, and alcohol-C in the clay fractions within the macroaggregates was higher than that microaggregates, whereas the relative amounts of illite, kaolinite, Fe(III), and aromatic-C had a reverse tendency. The hydroxy-interlayered vermiculite in clay fractions showed positive correlation with the amounts of C–C(H) (r = 0.93) and C–O (r = 0.96 *, p < 0.05). The concentration of Feo and Feo/Fed ratio was positively correlated with the amounts of C=C and C(O)O content in clay within aggregates. Long-term straw incorporation induced transformation of clay minerals and Fe oxide, which was selectively stabilized straw-derived organic compounds in clay fractions within soil aggregates. Full article
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Article
Temporal Movement of a Dieback Front in a Population of Parkinsonia in Northern Australia
Agronomy 2022, 12(2), 533; https://doi.org/10.3390/agronomy12020533 - 21 Feb 2022
Viewed by 332
Abstract
The temporal progress of Parkinsonia aculeata dieback through a well-established, naturally occurring dieback affected site was monitored using two transects over a seven-year period. This revealed the time and spatial dynamics underlying the nature of this disorder. Assessment of this site demonstrated a [...] Read more.
The temporal progress of Parkinsonia aculeata dieback through a well-established, naturally occurring dieback affected site was monitored using two transects over a seven-year period. This revealed the time and spatial dynamics underlying the nature of this disorder. Assessment of this site demonstrated a decline in individual plant health over consecutive years, with 98% of parkinsonia plants dying over the study period. Minimal recruitment of new plants led to a collapse in the parkinsonia population. Macrophomina phaseolina (Botryosphaeriaceae) was the only species with known pathogenicity on parkinsonia found in the transect site. This information provides a valuable insight into the timeframe involved in this disease process from infection through to plant death. This is the first research to date to assess the temporal movement of parkinsonia dieback. Full article
(This article belongs to the Section Weed Science and Weed Management)
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Article
Evaluation of Methods for Measuring Fusarium-Damaged Kernels of Wheat
Agronomy 2022, 12(2), 532; https://doi.org/10.3390/agronomy12020532 - 21 Feb 2022
Cited by 1 | Viewed by 758
Abstract
Fusarium head blight (FHB) is one of the most economically destructive diseases of wheat (Triticum aestivum L.), causing substantial yield and quality loss worldwide. Fusarium graminearum is the predominant causal pathogen of FHB in the U.S., and produces deoxynivalenol (DON), a mycotoxin [...] Read more.
Fusarium head blight (FHB) is one of the most economically destructive diseases of wheat (Triticum aestivum L.), causing substantial yield and quality loss worldwide. Fusarium graminearum is the predominant causal pathogen of FHB in the U.S., and produces deoxynivalenol (DON), a mycotoxin that accumulates in the grain throughout infection. FHB results in kernel damage, a visual symptom that is quantified by a human observer enumerating or estimating the percentage of Fusarium-damaged kernels (FDK) in a sample of grain. To date, FDK estimation is the most efficient and accurate method of predicting DON content without measuring presence in a laboratory. For this experiment, 1266 entries collectively representing elite varieties and SunGrains advanced breeding lines encompassing four inoculated FHB nurseries were represented in the analysis. All plots were subjected to a manual FDK count, both exact and estimated, near-infrared spectroscopy (NIR) analysis, DON laboratory analysis, and digital imaging seed phenotyping using the Vibe QM3 instrument developed by Vibe imaging analytics. Among the FDK analytical platforms used to establish percentage FDK within grain samples, Vibe QM3 showed the strongest prediction capabilities of DON content in experimental samples, R2 = 0.63, and higher yet when deployed as FDK GEBVs, R2 = 0.76. Additionally, Vibe QM3 was shown to detect a significant SNP association at locus S3B_9439629 within major FHB resistance quantitative trait locus (QTL) Fhb1. Visual estimates of FDK showed higher prediction capabilities of DON content in grain subsamples than previously expected when deployed as genomic estimated breeding values (GEBVs) (R2 = 0.71), and the highest accuracy in genomic prediction, followed by Vibe QM3 digital imaging, with average Pearson’s correlations of r = 0.594 and r = 0.588 between observed and predicted values, respectively. These results demonstrate that seed phenotyping using traditional or automated platforms to determine FDK boast various throughput and efficacy that must be weighed appropriately when determining application in breeding programs to screen for and develop resistance to FHB and DON accumulation in wheat germplasms. Full article
(This article belongs to the Special Issue Wheat Breeding: Procedures and Strategies – Series Ⅱ)
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Article
Effects of COVID-19 Pandemic on Agricultural Food Production among Smallholder Farmers in Northern Drakensberg Areas of Bergville, South Africa
Agronomy 2022, 12(2), 531; https://doi.org/10.3390/agronomy12020531 - 21 Feb 2022
Viewed by 780
Abstract
COVID-19 pandemic has greatly affected social and economic activities in the agriculture systems. The extent of pandemic disruptions on agriculture food production systems is lamentably scanty in rural areas. A survey was carried out in the Northern Drakensberg areas of Bergville, and it [...] Read more.
COVID-19 pandemic has greatly affected social and economic activities in the agriculture systems. The extent of pandemic disruptions on agriculture food production systems is lamentably scanty in rural areas. A survey was carried out in the Northern Drakensberg areas of Bergville, and it assessed the impact of COVID-19 on agricultural food production in smallholder farming systems comprising crop-livestock systems. A survey was conducted using structured questionnaires that measured the impact of COVID-19 within farming operations and average crop yield trends pre-COVID-19 and during COVID-19. Most farmers (77.1 to 92.4%) reported having limitations in accessing agricultural inputs of seeds, fertilizers, herbicides, fungicides, and insecticides during the COVID-19 pandemic. Results indicated a continuous decrease in yields of maize, dry beans, and soybeans across two years of cropping seasons during the COVID-19 pandemic. The study demonstrated that COVID-19 lockdowns accompanied by movement restrictions negatively impacted food production of staple crops (maize, dry beans, soybeans) despite suitable rains received during COVID-19 production periods. COVID-19 policies and legislations sensitive to the plight of poor rural communities are necessary as these communities are more reliant on local agricultural food production for their livelihoods and income. Strong co-operations must be established among input suppliers, smallholder farmers associations, extension services, and local retailers to assist smallholders to obtain inputs at local retailers even during COVID-19 lockdown restrictions. Full article
(This article belongs to the Special Issue COVID-19 Crises & Implications to Agri-Food Sector)
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Article
Measuring Soil Quality Indicators under Different Climate-Smart Land Uses across East African Climate-Smart Villages
Agronomy 2022, 12(2), 530; https://doi.org/10.3390/agronomy12020530 - 21 Feb 2022
Cited by 1 | Viewed by 549
Abstract
The present study assessed soil physical-chemical characteristics as reliable soil health indicators in six climate-smart land use types; agroforestry, community forest, cropland with soil and water conservation (SWC), crop land without SWC, grassland and control across climate-smart villages (CSVs) in Lushoto (Tanzania), Hoima [...] Read more.
The present study assessed soil physical-chemical characteristics as reliable soil health indicators in six climate-smart land use types; agroforestry, community forest, cropland with soil and water conservation (SWC), crop land without SWC, grassland and control across climate-smart villages (CSVs) in Lushoto (Tanzania), Hoima (Uganda), Wote and Nyando (Kenya). Soils were sampled at three depths; 0–15 cm, 15–45 cm and 45–100 cm and then analyzed for bulk density (BD), pH, exchangeable bases (Ca, Mg, K, Na), extractable Fe, Mn, Zn, exchangeable acidity (ExAc), Electrical conductivity (EC), total carbon (TC), total nitrogen (TN) and cation exchange capacity (CEC). Land use types and sampling depths significantly affected soil properties (p < 0.05), High bulk density (BD) was measured at 45–100 cm depth in grassland (1.47 g/cm3) and crop land (1.50 g/cm3) in Kenya and Tanzania, respectively. BD in Ugandan grasslands was statistically lower (p < 0.05) than BD in other land use types at all depths. Soil pH of surface soil (0–15 cm) ranged from 6.67 ± 0.67 (agroforestry) to 6.27 ± 0.85 (grassland). Ex. bases (Ca, Mg, K and Na) and extractable Fe, Mn, Zn, ExAc, EC, TC, TN and CEC were significantly affected by land uses (p ≤ 0.05). Soil properties were significantly correlated, a positive correlation between silt % (p < 0.01) and pH, sand and Ca (p < 0.05). EC and pH, exchangeable Ca, exchangeable bases, exchangeable K and C: N ratio was observed. There was a negative correlation (p < 0.05) between pH and clay. The study has shown that improving soil properties using land use systems leads to an increase in soil nutrients. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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Article
The Essential-Oil-Bearing Rose Collection Variability Study in Terms of Biochemical Parameters
Agronomy 2022, 12(2), 529; https://doi.org/10.3390/agronomy12020529 - 20 Feb 2022
Viewed by 397
Abstract
The primary task when breeding new varieties of essential-oil-bearing rose is to increase the essential oil content and quality. The purpose of the present research is to study the essential-oil-bearing rose collection variability in terms of the essential oil content and component composition [...] Read more.
The primary task when breeding new varieties of essential-oil-bearing rose is to increase the essential oil content and quality. The purpose of the present research is to study the essential-oil-bearing rose collection variability in terms of the essential oil content and component composition and to identify opportunities for isolating the specimens promising for selection. The study of a collection of 112 specimens was carried out in 2017–2020 in the context of the piedmont of Crimea. The decanted essential oil content was determined using the hydrodistillation method. The component composition of rose essential oil was analyzed by gas chromatography on Crystal 5000.2. The essential oil components were identified by comparing their Kovats retention indices to the literature values. A high variability in the essential oil content in the collection (Cv = 36.3% at the average, over 4 years) and the major components content in the essential oil (Cv = 22.1–45.9%) was found. In the context of the piedmont of Crimea, the major components’ percentage content in essential oil from all the specimens including the five Bulgarian varieties did not meet the GOST ISO 9842-2017 standard requirements. This is indicative of a high-degree sensitivity to the soil and weather conditions in the region. It was found that the citronellol, geraniol, and nerol content in essential oil dropped significantly in extreme high temperature and drought conditions. Seven specimens rich in essential oil contained in the raw plant material (0.030–0.049%) and thirteen specimens with a high yield of concrete (0.31–0.39%) were identified and have been recommended for inclusion in the breeding process. Full article
(This article belongs to the Special Issue Innovative Technologies in Crop Production and Animal Husbandry)
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Article
Considerations on Field Methodology for Macrofungi Studies in Fragmented Forests of Mediterranean Agricultural Landscapes
Agronomy 2022, 12(2), 528; https://doi.org/10.3390/agronomy12020528 - 20 Feb 2022
Viewed by 464
Abstract
The methodology used for the determination of macrofungal diversity in Mediterranean areas differs in the time of sampling and the number of years displayed, making it difficult to compare results. Furthermore, the results could be refuted because the studies are being conducted over [...] Read more.
The methodology used for the determination of macrofungal diversity in Mediterranean areas differs in the time of sampling and the number of years displayed, making it difficult to compare results. Furthermore, the results could be refuted because the studies are being conducted over an insufficient number of years or without considering the variation of the meteorological conditions from one year to the next and its effects on fruiting time, which might not fit the sampling. In order to optimize field work on fungal fruiting in Mediterranean environments dominated by holm oak (Quercus ilex L.), a weekly field analysis of macrofungal diversity from February 2009 to June 2013 was carried out in a Mediterranean holm oak forest in the middle-west of the Iberian Peninsula. The results revealed that fruiting bodies appeared throughout the year and that there was a delay in autumn fruiting, overlapping with spring. All this seems to indicate that weekly collection throughout the year and for a period of two years could be sufficient to estimate the macrofungal biodiversity of this ecosystem. Full article
(This article belongs to the Special Issue Resilience in Soils and Land Use)
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Article
Impact of Olive Trees on the Microclimatic and Edaphic Environment of the Understorey Durum Wheat in an Alley Orchard of the Mediterranean Area
Agronomy 2022, 12(2), 527; https://doi.org/10.3390/agronomy12020527 - 20 Feb 2022
Viewed by 441
Abstract
In the current context of climate change, the impact of trees in agroforestry systems is expected to mitigate water and heat stresses, particularly in semi-arid environments. Within this framework, in a two-year trial conducted at INRAE in Southern France, the dynamics of microclimatic [...] Read more.
In the current context of climate change, the impact of trees in agroforestry systems is expected to mitigate water and heat stresses, particularly in semi-arid environments. Within this framework, in a two-year trial conducted at INRAE in Southern France, the dynamics of microclimatic parameters and the edaphic environment of durum wheat were investigated under a yearly-pruned (AF) and a never-pruned (AF+) 6-m apart alley olive orchard, in comparison with controls under full sun. Here it was recorded a reduction of photosynthetic active radiation (PAR) by 30% and 51% in AF and AF+, respectively, during the wheat cycle, together with a marked reduction of wind speed compared to controls (–85% in AF and −99% in AF+). A significant buffer effect was also highlighted for air temperature, averagely +1.7 °C during the night and −3.2 °C during the daytime under the moderate shading of AF. The positive effect of trees on soil water conservation increased with the intensity of shading, particularly during the critical wheat stage of grain filling, with benefits on wheat root mycorrhization, and NH4+ and NO3 abundance in the arable layer. Despite some of the environmental modifications being favorable for the understorey wheat, these were not translated into yield improvements, suggesting that the severe shading associated with the small inter-row and evergreen trees has a prevailing effect, that requires to be managed through appropriate tree pruning. Full article
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Article
Development of Pedotransfer Functions to Predict Soil Physical Properties in Southern Quebec (Canada)
Agronomy 2022, 12(2), 526; https://doi.org/10.3390/agronomy12020526 - 20 Feb 2022
Viewed by 489
Abstract
Pedotransfer functions (PTFs) are empirical fits to soil property data and have been used as an alternative tool to in situ measurements for estimating soil hydraulic properties for the last few decades. PTFs of Saxton and Rawls, 2006 (PTFs’S&R.2006) are some of the [...] Read more.
Pedotransfer functions (PTFs) are empirical fits to soil property data and have been used as an alternative tool to in situ measurements for estimating soil hydraulic properties for the last few decades. PTFs of Saxton and Rawls, 2006 (PTFs’S&R.2006) are some of the most widely used because of their global aspect. However, empirical functions yield more accurate results when trained locally. This study proposes a set of agricultural PTFs developed for southern Quebec, Canada for three horizons (A, B, and C). Four response variables (bulk density (ρb), saturated hydraulic conductivity (Ksat), volumetric water content at field capacity (θ33), and permanent wilting point (θ1500)) and four predictors (clay, silt, organic carbon, and coarse fragment percentages) were used in this modeling process. The new PTFs were trained using the stepwise forward regression (SFR) and canonical correlation analysis (CCA) algorithms. The CCA- and SFR-PTFs were in most cases more accurate. Θ1500 and at θ33 estimates were improved with the SFR. The ρb in the A horizon was moderately estimated by the PTFs’S&R.2006, while the CCA- and SFR-PTFs performed equally well for the B and C horizons, yet qualified weak. However, for all PTFs for all horizons, Ksat estimates were unacceptable. Estimation of ρb and Ksat could be improved by considering other morphological predictors (soil structure, drainage information, etc.). Full article
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Article
Trapping of Ceratitis capitata Using the Low-Cost and Non-Toxic Attractant Biodelear
Agronomy 2022, 12(2), 525; https://doi.org/10.3390/agronomy12020525 - 20 Feb 2022
Viewed by 380
Abstract
Trapping is considered a powerful tool in the monitoring and control of fruit flies of high economic importance such as the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae). However, the cost of trapping and, in some cases, the safety of the chemicals used [...] Read more.
Trapping is considered a powerful tool in the monitoring and control of fruit flies of high economic importance such as the Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae). However, the cost of trapping and, in some cases, the safety of the chemicals used as baits are concerning for growers and the environment. Here we present a novel, low cost, environmentally friendly, female-specific bait for C. capitata, called Biodelear, that consists of a mixture of attracting compounds such us pyrazines, pyranones and amorphous nitrogen-based polymers. The new bait was compared to the commercially available attractant Biolure® (Suterra LLC, Bend, OR, USA) in Greece. McPhail-type traps were deployed in an orange orchard located in Athens. Five traps per treatment were used for several weeks during 2009 and four traps per treatment in 2010. Traps contained either 17 g of Biodelear or one Biolure Unipack dispenser. The results showed that both baits were highly efficient in attracting C. capitata females, and to a lesser extent, males. Although Biolure initially appeared to outperform Biodelear, later in the season the two attractants converged in efficacy. In both years, female captures were similar in traps baited with Biolure and Biodelear. However, male captures were higher in Biodelear-baited traps in 2010. In addition, Biodelear seemed to be longer lasting than Biolure, despite not being formulated into a slow-release dispersion system. The low cost of Biodelear and its strong, long-lasting effects render it suitable for mass trapping of the Mediterranean fruit fly. Full article
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Article
The Influence of Different Cooling Systems on the Microclimate, Photosynthetic Activity and Yield of a Tomato Crops (Lycopersicum esculentum Mill.) in Mediterranean Greenhouses
Agronomy 2022, 12(2), 524; https://doi.org/10.3390/agronomy12020524 - 19 Feb 2022
Viewed by 504
Abstract
The purpose of this study was to analyse the effect of different evaporative cooling systems compared to natural ventilation on the microclimate, photosynthetic activity and yield of a tomato crop (Lycopersicum esculentum Mill.) in a spring-summer cycle. In this study, the expenditure [...] Read more.
The purpose of this study was to analyse the effect of different evaporative cooling systems compared to natural ventilation on the microclimate, photosynthetic activity and yield of a tomato crop (Lycopersicum esculentum Mill.) in a spring-summer cycle. In this study, the expenditure of electricity and water caused by the different refrigeration systems and their economic cost was analysed. The study was carried out in three multi-span greenhouses: (i) a greenhouse with evaporative pads and fans and natural ventilation (PS + NV); (ii) a greenhouse with a fog system and natural ventilation (FS + NV); (iii) a greenhouse only with natural ventilation (NV). The photosynthetic activity was higher in the greenhouse with natural ventilation (14.7 µmol CO2 m−2 s−1) than in the greenhouse with the pad-fan system (14.6 µmol CO2 m−2 s−1; without a statistically significant difference) and in the greenhouse with fog system (13.4 µmol CO2 m−2 s−1; with a statistically significant difference). The production was higher in the greenhouse with the pad-fan system (5.0 kg m−2) than in the greenhouse with natural ventilation (4.8 kg m−2; without a statistically significant difference) and in the greenhouse with a fog system (4.5 kg m−2; with a statistically significant difference). In general, photosynthetic activity and crop production increased as the maximum temperature (and the number of hours of exposure to high temperatures) decreased. It has been observed that the improvement in temperature conditions inside the greenhouses in spring-summer cycles produces increases in the photosynthetic activity of the tomato crop and, consequently, growth in production. The energy and water consumption derived from the use of active-type cooling systems have not been offset by a representative improvement in photosynthetic activity or crop production. Full article
(This article belongs to the Special Issue Characteristics and Technology in Mediterranean Agriculture)
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Article
Dual Response Optimization of Ultrasound-Assisted Oil Extraction from Red Fruit (Pandanus conoideus): Recovery and Total Phenolic Compounds
Agronomy 2022, 12(2), 523; https://doi.org/10.3390/agronomy12020523 - 19 Feb 2022
Viewed by 550
Abstract
Red fruit oil (RFO) is a high-value oil that contains functional compounds, mainly phenolic compounds, providing antioxidant activity. Therefore, an optimal extraction method is essential to recover the RFO and phenolic compounds simultaneously. This research aimed to optimize the ultrasound-assisted extraction (UAE) for [...] Read more.
Red fruit oil (RFO) is a high-value oil that contains functional compounds, mainly phenolic compounds, providing antioxidant activity. Therefore, an optimal extraction method is essential to recover the RFO and phenolic compounds simultaneously. This research aimed to optimize the ultrasound-assisted extraction (UAE) for oil from red fruit using the Box-Behnken design combined with response surface methodology. The studied UAE factors, including sample-to-solvent ratio (1:3, 1:2, and 1:1 g mL−1), extraction temperature (60, 75, and 90 °C), and pulse duty-cycle (0.20, 0.50, and 0.80 s−1). Analysis of variance revealed that the three studied factors significantly influenced the recovered RFO, while the level of total phenolic compounds in the extracts was defined merely by extraction temperature (p < 0.05). These significant factors were then included in the optimization models (R2 > 0.99, lack-of-fit p > 0.05). The proposed UAE setting by the multiresponse optimization was an extraction temperature of 67 °C, a pulse duty-cycle of 0.50 s−1, and a sample-to-solvent ratio of 1:2.5 g mL−1. Subsequently, the extraction kinetic was evaluated, confirming full recovery at 60 min of extraction time. The developed method was then applied to extract six red fruit clones. Mbarugum clones provided high RFO recovery (9.60%), with an uppermost total phenolic compound of (42.63 mg GAE g−1) among the six red fruit clones. Additionally, the resulting RFO showed eminent antioxidant activities, indicated by excellent values of IC50 DPPH (37.69 mg L−1), IC50 FIC (30.43 mg L−1), FRAP reducing power (63.55 mg AAEA g−1), and IC50 ABTS (93.88 mg L−1). In contrast with a wet rendering method, UAE enhanced the RFO recovery by 53.02%, resulting in a higher level of total phenolic compounds. Henceforth, the proposed UAE method is a promising technique to substitute conventional oil production in the food and pharmaceutical industries. Full article
(This article belongs to the Special Issue Extraction and Analysis of Bioactive Compounds in Crops)
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Review
Utilizing Genomic Selection for Wheat Population Development and Improvement
Agronomy 2022, 12(2), 522; https://doi.org/10.3390/agronomy12020522 - 19 Feb 2022
Viewed by 935
Abstract
Wheat (Triticum aestivum L.) breeding programs can take over a decade to release a new variety. However, new methods of selection, such as genomic selection (GS), must be integrated to decrease the time it takes to release new varieties to meet the [...] Read more.
Wheat (Triticum aestivum L.) breeding programs can take over a decade to release a new variety. However, new methods of selection, such as genomic selection (GS), must be integrated to decrease the time it takes to release new varieties to meet the demand of a growing population. The implementation of GS into breeding programs is still being explored, with many studies showing its potential to change wheat breeding through achieving higher genetic gain. In this review, we explore the integration of GS for a wheat breeding program by redesigning the traditional breeding pipeline to implement GS. We propose implementing a two-part breeding strategy by differentiating between population improvement and product development. The implementation of GS in the product development pipeline can be integrated into most stages and can predict within and across breeding cycles. Additionally, we explore optimizing the population improvement strategy through GS recurrent selection schemes to reduce crossing cycle time and significantly increase genetic gain. The recurrent selection schemes can be optimized for parental selection, maintenance of genetic variation, and optimal cross-prediction. Overall, we outline the ability to increase the genetic gain of a breeding program by implementing GS and a two-part breeding strategy. Full article
(This article belongs to the Special Issue Wheat Breeding: Procedures and Strategies – Series Ⅱ)
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Article
Biodisinfection as a Profitable Fertilization Method for Horticultural Crops in the Framework of the Circular Economy
Agronomy 2022, 12(2), 521; https://doi.org/10.3390/agronomy12020521 - 19 Feb 2022
Cited by 1 | Viewed by 448
Abstract
Intensive agriculture has resulted in various environmental impacts that affect ecosystems. In some cases, the application of conventional fertilizers has deteriorated water quality, which includes the marine environment. For this reason, institutions have designed various strategies based on the principles of the circular [...] Read more.
Intensive agriculture has resulted in various environmental impacts that affect ecosystems. In some cases, the application of conventional fertilizers has deteriorated water quality, which includes the marine environment. For this reason, institutions have designed various strategies based on the principles of the circular economy and the bioeconomy. Both of these dynamics aim to reduce excessive fertilization and to inhibit the negative externalities it generates. In our work, a field trial is presented in which a 100% reduction in conventional inorganic fertilizers has been evaluated through a production methodology based on fertilization with reused plant debris in combination with other organic compounds. Based on one tomato crop, the profitability of this production technique has been analyzed in comparison with other conventional vegetable production techniques. The productivity and economic yield of the alternative crop was similar to that of the conventional crop, with a 37.2% decrease in water consumption. The reuse of biomass reduced production costs by 4.8%, while the addition of other organic amendments increased them by up to 22%. The results of our trial show that farms are more sustainable and more profitable from a circular point of view when using these strategies. Full article
(This article belongs to the Special Issue Circular Economy and Sustainable Development in Agriculture)
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Article
An Air Convection Wall with a Hollow Structure in Chinese Solar Greenhouses: Thermal Performance and Effects on Microclimate
Agronomy 2022, 12(2), 520; https://doi.org/10.3390/agronomy12020520 - 19 Feb 2022
Viewed by 379
Abstract
A Chinese solar greenhouse (CSG) is a horticultural facility that uses solar energy to promote a growth environment for crops and provides high-efficiency thermal storage performance to meet the demand of vegetables’ growth in winter. Besides being an important load-bearing structure in CSGs, [...] Read more.
A Chinese solar greenhouse (CSG) is a horticultural facility that uses solar energy to promote a growth environment for crops and provides high-efficiency thermal storage performance to meet the demand of vegetables’ growth in winter. Besides being an important load-bearing structure in CSGs, the north wall is a heat sink, storing during the day in order to act as a heat source during the night. At times, the night temperature is lower than the minimum growth temperature requirement of vegetables, and the additional heating is needed. Therefore, optimizing the heat storage and release performance of the north wall in a CSG is an important approach for improving growth environment and reducing consumption of fossil fuel. This study proposes a heat storage north wall with a hollow layer on the basis of air convection, aiming to optimize the utilization of solar energy in CSGs. By the air convection effects, the hollow layer collects and stores surplus solar energy in the air during the day and transfers it to the cultivation space for heating at night. Additionally, field tests were conducted to compare the natural and forced convection strategies via airflow and heat transfer efficiency. The final effect on the indoor temperature ensured that the lowest temperatures at night were above 5 °C under both the natural and forced convection strategies during the winter in the Beijing suburbs where the average minimum temperature is below −10.8 °C during the experimental period. The hollow structure improves the utilization efficiency of solar energy in CSGs and ensures winter production efficiency in northern China. Full article
(This article belongs to the Special Issue Energy Efficient Greenhouses and Energy Saving Technologies)
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Article
Seasonal Dynamics of Soil Bacterial Community under Long-Term Abandoned Cropland in Boreal Climate
Agronomy 2022, 12(2), 519; https://doi.org/10.3390/agronomy12020519 - 19 Feb 2022
Viewed by 387
Abstract
The collapse of collective farming in Russia after 1990 led to the abandonment of 23% of the agricultural area. Microbial biomass is a transit pool between fresh and soil organic matter; therefore, structural changes in soil microbial community determine the carbon cycle processes [...] Read more.
The collapse of collective farming in Russia after 1990 led to the abandonment of 23% of the agricultural area. Microbial biomass is a transit pool between fresh and soil organic matter; therefore, structural changes in soil microbial community determine the carbon cycle processes caused by self-restoration of arable lands after abandonment. Here, we assessed the influence of monthly changes in moisture and temperature on the bacterial community structure and abundance in Retisols under long-term abandoned cropland. Two periods with pronounced differences in bacterial properties were revealed: the growing period from March to September and the dormant period from October to February. The growing period was characterized by higher bacterial abundance and diversity compared to the dormant period. The relative abundances of the bacterial community dominants (Alpha-, Gamma- and Deltaproteobacteria, subgroup 6 of phylum Acidobacteria) did not change significantly over the year, either in total or active communities. The relative abundances of Bacteroidetes and Verrucomicrobia increased in the growing period, whereas Actinobacteria and Chloroflexi were more abundant in the dormant period. The microbial gene abundances positively correlated with soil and air temperature, but not with soil moisture. Thus, the seasonal dynamics of soil microbial communities are closely related to soil temperature and should be considered when assessing carbon cycles in abandoned lands. Full article
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Review
Precision Pollination Strategies for Advancing Horticultural Tomato Crop Production
Agronomy 2022, 12(2), 518; https://doi.org/10.3390/agronomy12020518 - 18 Feb 2022
Viewed by 1121
Abstract
Global climate change and anthropological activities have led to a decline in insect pollinators worldwide. Agricultural globalisation and intensification have also removed crops from their natural insect pollinators, and sparked research to identify alternate natural insect pollinators and artificial technologies. In certain countries [...] Read more.
Global climate change and anthropological activities have led to a decline in insect pollinators worldwide. Agricultural globalisation and intensification have also removed crops from their natural insect pollinators, and sparked research to identify alternate natural insect pollinators and artificial technologies. In certain countries such as Australia the importation of commercial insect pollinators is prohibited, necessitating manual labour to stimulate floral pollination. Artificial pollination technologies are now increasingly essential as the demand for food grown in protected facilities increases worldwide. For tomato fruits, precision pollination has the ability to vastly improve their seed set, size, yield, and quality under optimal environmental conditions and has become financially beneficial. Like many crops from the Solanaceae, tomatoes have a unique self-pollinating mechanism that requires stimulation of the floral organs to release pollen from the poricidal anthers. This review investigates various mechanisms employed to pollinate tomato flowers and discusses emerging precision pollination technologies. The advantages and disadvantages of various pollinating technologies currently available in the protected-cropping industry are described. We provide a buzz perspective on new promising pollination technologies involving robotic air and acoustic devices that are still in their nascency and could provide non-contact techniques to automate pollination for the tomato horticultural industry. Full article
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Article
Effects of Short-Term Tillage Managements on CH4 and N2O Emissions from a Double-Cropping Rice Field in Southern of China
Agronomy 2022, 12(2), 517; https://doi.org/10.3390/agronomy12020517 - 18 Feb 2022
Cited by 1 | Viewed by 419
Abstract
Soil carbon (C) content plays an important role in maintaining or increasing soil quality and soil fertility. However, the impacts of different tillage and crop residue incorporation managements on greenhouse gas (GHG) emissions from paddy fields under the double-cropping rice (Oryza sativa [...] Read more.
Soil carbon (C) content plays an important role in maintaining or increasing soil quality and soil fertility. However, the impacts of different tillage and crop residue incorporation managements on greenhouse gas (GHG) emissions from paddy fields under the double-cropping rice (Oryza sativa L.) system in southern China still need further study. Therefore, a field experiment was conducted to determine the impacts of different short-term (5-years) tillage and crop residue incorporation managements on soil organic carbon (SOC) content, SOC stock, and GHG emissions from paddy fields under the double-cropping rice system in southern China. The field experiment included four tillage treatments: rotary tillage with all crop residues removed as a control (RTO), conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), and no-tillage with crop residue retention (NT). These results indicated that SOC stock in paddy fields with CT, RT, and NT treatments increased by 4.64, 3.60, 3.50 Mg ha−1 and 4.68, 4.21, and 4.04 Mg ha−1 in 2019 and 2020, respectively, compared with RTO treatment. The results showed that early rice and late rice yield with CT treatment increased by 7.22% and 19.99% in 2019 and 6.19% and 6.40% in 2020, respectively, compared with RTO treatment. A two-year (2019–2020) investigation of GHG results indicated that methane emissions from paddy fields with NT treatment were decreased, but nitrous oxide emissions from paddy fields were increased. The lowest mean global warming potential (GWP) and per yield GWP carbon dioxide were found with NT treatment, compared to RT and CT treatments. Therefore, it was a beneficial practice for maintaining SOC stock and decreasing GHG mitigation under the double-cropping rice system in southern China by applying no-tillage with crop residue retention management. Full article
(This article belongs to the Special Issue In Memory of Professor Longping Yuan, the Father of Hybrid Rice)
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Article
Combination of Limited Meteorological Data for Predicting Reference Crop Evapotranspiration Using Artificial Neural Network Method
Agronomy 2022, 12(2), 516; https://doi.org/10.3390/agronomy12020516 - 18 Feb 2022
Viewed by 486
Abstract
Reference crop evapotranspiration (ETo) is an important component of the hydrological cycle that is used for water resource planning, irrigation, and agricultural management, as well as in other hydrological processes. The aim of this study was to estimate the ETo [...] Read more.
Reference crop evapotranspiration (ETo) is an important component of the hydrological cycle that is used for water resource planning, irrigation, and agricultural management, as well as in other hydrological processes. The aim of this study was to estimate the ETo based on limited meteorological data using an artificial neural network (ANN) method. The daily data of minimum temperature (Tmin), maximum temperature (Tmax), mean temperature (Tmean), solar radiation (SR), humidity (H), wind speed (WS), sunshine hours (Ssh), maximum global radiation (gradmax), minimum global radiation (gradmin), day length, and ETo data were obtained over the long-term period from 1969 to 2019. The analysed data were divided into two parts from 1969 to 2007 and from 2008 to 2019 for model training and testing, respectively. The optimal ANN for forecasting ETo included Tmax, Tmin, H, and SR at hidden layers (4, 3); gradmin, SR, and WS at (6, 4); SR, day length, Ssh, and Tmean at (3, 2); all collected parameters at hidden layer (5, 4). The results showed different alternative methods for estimation of ETo in case of a lack of climate data with high performance. Models using ANN can help promote the decision-making for water managers, designers, and development planners. Full article
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Article
Evaluation of ‘Lorca’ Cultivar Aptitude for Minimally Processed Artichoke
Agronomy 2022, 12(2), 515; https://doi.org/10.3390/agronomy12020515 - 18 Feb 2022
Viewed by 388
Abstract
Previous research works have reported that ‘Lorca’ artichoke cultivar presents a lower total phenolic content than other cultivars rich in phenolic compounds, which could show a lower susceptibility to enzymatic browning and increase its aptitude for fresh-cut processing. The aim of this study [...] Read more.
Previous research works have reported that ‘Lorca’ artichoke cultivar presents a lower total phenolic content than other cultivars rich in phenolic compounds, which could show a lower susceptibility to enzymatic browning and increase its aptitude for fresh-cut processing. The aim of this study was to analyze the total phenolic content as well as browning evaluation by image analysis and polyphenol oxidase (PPO) enzyme activity in ‘Lorca’ cultivar in order to characterize the key factors which influence its phenolic levels for minimally processed artichokes. Thus, artichokes were harvested and classified on three head orders (main, secondary, and tertiary), as well as three development stages (initial, intermediate, and advanced). Variance components analysis was carried out for total phenolic content considering three factors: plant, flower head order, and internal development stage. For the first time, the internal development stage has been related to total phenolic content, and results showed that artichoke head order and internal development stage were responsible for a variability of 22.17% and 15.55%, respectively. Main artichoke heads and those at the advanced development stage presented the lowest phenolic concentration as well as the lowest PPO activity; therefore, they exhibit the lowest browning process, which could increase their use in ready-to-eat products at market. Full article
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Review
Optical Spectrometry to Determine Nutrient Concentrations and other Physicochemical Parameters in Liquid Organic Manures: A Review
Agronomy 2022, 12(2), 514; https://doi.org/10.3390/agronomy12020514 - 18 Feb 2022
Viewed by 492
Abstract
Nutrient concentrations in livestock manures and biogas digestates show a huge variability due to disparities in animal husbandry systems concerning animal species, feed composition, etc. Therefore, a nutrient estimation based on recommendation tables is not reliable when the exact chemical composition is needed. [...] Read more.
Nutrient concentrations in livestock manures and biogas digestates show a huge variability due to disparities in animal husbandry systems concerning animal species, feed composition, etc. Therefore, a nutrient estimation based on recommendation tables is not reliable when the exact chemical composition is needed. The alternative, to analyse representative fertilizer samples in a standard laboratory, is too time- and cost-intensive to be an accepted routine method for farmers. However, precise knowledge about the actual nutrient concentrations in liquid organic fertilizers is a prerequisite to ensure optimal nutrient supply for growing crops and on the other hand to avoid environmental problems caused by overfertilization. Therefore, spectrometric methods receive increasing attention as fast and low-cost alternatives. This review summarizes the present state of research based on optical spectrometry used at laboratory and field scale for predicting several parameters of liquid organic manures. It emphasizes three categories: (1) physicochemical parameters, e.g., dry matter, pH, and electrical conductivity; (2) main plant nutrients, i.e., total nitrogen, ammonium nitrogen, phosphorus, potassium, magnesium, calcium, and sulfur; and (3) micronutrients, i.e., manganese, iron, copper, and zinc. Furthermore, the commonly used sample preparation techniques, spectrometer types, measuring modes, and chemometric methods are presented. The primarily promising scientific results of the last 30 years contributed to the fact that near-infrared spectrometry (NIRS) was established in commercial laboratories as an alternative method to wet chemical standard methods. Furthermore, companies developed technical setups using NIRS for on-line applications of liquid organic manures. Thus, NIRS seems to have evolved to a competitive measurement procedure, although parts of this technique still need to be improved to ensure sufficient accuracy, especially in quality management. Full article
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Article
Effects of Closing Cut Date and Nitrogen Fertilization on Seed Yield and Seed Quality in Two Novel Cultivars of Urochloa spp.
Agronomy 2022, 12(2), 513; https://doi.org/10.3390/agronomy12020513 - 18 Feb 2022
Viewed by 328
Abstract
Two field trials were conducted in Thailand to determine an appropriate closing cut date (CCD) and rate of nitrogen application (N-rate) to maximize seed yield and seed quality of the two novel cultivars (cv.) of Urochloa spp. (Synonym Brachiaria spp.), cv. ‘OKI-1’ (an [...] Read more.
Two field trials were conducted in Thailand to determine an appropriate closing cut date (CCD) and rate of nitrogen application (N-rate) to maximize seed yield and seed quality of the two novel cultivars (cv.) of Urochloa spp. (Synonym Brachiaria spp.), cv. ‘OKI-1’ (an open-pollinated tetraploid Urochloa ruziziensis (R. Germ. and C.M. Evrard) Crins originated from cv. ‘Miyaokikoku-ichigou’) and cv. ‘Br-203’ (U. ruziziensis cv. ‘Miyaokikoku-ichigou’ × U. hybrid cv. ‘Mulato’). The following treatments were evaluated in this study: four CCDs (uncut, 15 June, 1 July, and 15 July) and four N-rates (0, 50, 100, and 150 kg/ha). The cv. ‘OKI-1’ showed somewhat differences in tiller number/m2 (TN), fertile tiller percentage (FTP), inflorescence number/tiller (IN/T) and spikelet number/raceme (SN/R) with the CCD, while the cv. ‘Br-203’ showed only in SN/R. However, TN and SN/R were highest for 15 June, and FTP and IN/T were highest for 1 July in cv. ‘OKI-1’. The cv. ‘OKI-1’ showed the highest total seed yield (TSY), pure seed yield (PSY), and pure germinated seed yield (PGSY) for 1 July, followed by 15 June, and the cv. ‘Br-203’ showed the highest TSY, PSY, and PGSY for 15 July, followed by 1 July. Nitrogen (N) fertilization showed a negative effect on TSY for both the cultivars due to the higher N content in the soil. Withholding N fertilizer, a CCD in late-June to early-July and early-July to mid-July is recommended for cv. ‘OKI-1’ and cv. ‘Br-203’, respectively. Full article
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Article
Phytotoxicity and Plant Defence Induction by Cinnamomum cassia Essential Oil Application on Malus domestica Tree: A Molecular Approach
Agronomy 2022, 12(2), 512; https://doi.org/10.3390/agronomy12020512 - 18 Feb 2022
Viewed by 392
Abstract
Essential oils (EOs) are actively investigated as an alternative to numerous synthetic biocide products. Due to their large spectra of biological activities, the impact of EOs on non-target organisms should be characterized for biopesticide development purposes. In this study the potential phytotoxicity of [...] Read more.
Essential oils (EOs) are actively investigated as an alternative to numerous synthetic biocide products. Due to their large spectra of biological activities, the impact of EOs on non-target organisms should be characterized for biopesticide development purposes. In this study the potential phytotoxicity of Cinnamomum cassia EO (CEO) on apple trees (Malus domestica) was investigated in terms of oxidative burst (glutathione redox state) and damage (malondialdehyde). At 2%, CEO concentration the reduced glutathione leaf content drops from 269.6 ± 45.8 to 143 ± 28.4 nmol g−1FW, after 30 min, illustrating a rapid and strong oxidative burst. Regarding oxidative damage, malondialdehyde increased significantly 24 h post application to 10.7 ± 3.05 nmol g−1FW. Plant defence induction was previously suspected after trans-cinnamaldehyde (CEO main compound) application. Therefore, the elicitor potential was investigated by qRT-PCR, on the expression level of 29 genes related to major defence pathways (PR protein, secondary metabolism, oxidative stress, parietal modification). Multivariate analysis and increased expression levels suggest induction of systemic resistance. Hence, the present research illustrates the dose–dependent phytotoxicity of CEO in terms of lipid peroxidation. Transcriptional data illustrates the elicitor properties of CEO. These findings can help to design pest management strategies considering both their risks (phytotoxicity) and benefits (defence activation combined with direct biocide properties). Full article
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