Agroecology and Organic Horticulture

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Agricultural Biosystem and Biological Engineering".

Deadline for manuscript submissions: closed (15 April 2023) | Viewed by 69412

Special Issue Editors


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Guest Editor
Département de Phytologie, Centre de Recherche et d’Innovation sur les Végétaux (CRIV), Université Laval, Pavillon Envirotron, Local 2120, Québec City, QC G1V 0A6, Canada
Interests: organic and agroecology horticulture; sustainable greenhouse and controlled environment production systems; water and nutrient crop management; sustainable growing media; biostimulants; soil–microbiota–plant interaction; crop waste management; crop physiology

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Guest Editor
Centre for Agroecology, Water and Resilience (CAWR), Coventry University, Priory St, Coventry CV1 5FB, UK
Interests: organic horticulture; agroecology including urban agroecology, agroforestry, fruit trees, legumes and vegetables; greenhouse crops; horticultural and agricultural economics; ecological economics; sustainability assessment; organic farm management; food policy; better inputs for organic like peat-free plastic-free zero-pollution; vegan organic
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Special Issue Information

Dear Colleagues,

In the last decade, substantial research progress has been made via several national and European research programs (e.g., Horizon 2020, CORE Organic network, AAFC Science Organic Cluster) and platforms (e.g., TP Organics) in order to develop innovative and sustainable organic food systems. Consequently, organic cultivated area has increased by 97% and the global organic food market reached 95 billion euros (105.5 billion US dollars) in 2018; organic horticulture represents around 699,324 ha of organic arable land and 4,734,094 ha of permanent cropland. Advances made during that time period were mainly related to nutrient budgeting and resource use efficiency, sustainable and resilient cropping systems, soil management and plant-associated microbes, environmental pest and weed control and breeding. The present Special Issue will focus on the recent advancements in sustainable organic horticulture growing systems with an emphasis on soil health and plant resilience to biotic and abiotic stresses. Research papers, communications, and review articles are all welcome. In particular, we encourage contributions covering innovative soil fertility management for improving soil biodiversity and plant resilience, agroecological service crops, the benefits of biofertilizers and biostimulants for improving plant resilience, yield and product quality of organic horticulture crops. Specific attention will be given to studies that explore the use of plant–microbe interactions in plant breeding and pest control as well as the impact of cultural practices and innovative design and crop management on soil microbiota communities and functionality. Attention will also be given to studies that propose circular and zero-waste production systems, diversified production systems, decision support systems and artificial intelligence for crop management, alternatives to the use of copper, peat and animal-based fertilizers, and integrated growing strategies and tools to better use resources (e.g., water, nutrients, energy) and face climatic changes, as well as the evaluation of the environmental and economic impact of new inputs, practices or systems.

Prof. Dr. Martine Dorais
Prof. Dr. Ulrich Schmutz
Guest Editors

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Keywords

  • Horticulture
  • Agroecology
  • Sustainability
  • Microbiota
  • Biostimulant
  • Fertilizers and nutrient management
  • Soil health
  • Plant resilience
  • Plant protection
  • Water management

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Published Papers (13 papers)

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17 pages, 336 KiB  
Article
Optimizing Light Use Efficiency and Quality of Indoor Organically Grown Leafy Greens by Using Different Lighting Strategies
by Laurent Boucher, Thi-Thuy-An Nguyen, Annie Brégard, Steeve Pepin and Martine Dorais
Agronomy 2023, 13(10), 2582; https://doi.org/10.3390/agronomy13102582 - 9 Oct 2023
Viewed by 2646
Abstract
Vertical farming is experiencing significant growth, and the optimization of artificial lighting is essential for enhancing the sustainability of this growing system. Therefore, the aim of this study was to examine how light segmentation, the incorporation of a low-intensity lighting phase known as [...] Read more.
Vertical farming is experiencing significant growth, and the optimization of artificial lighting is essential for enhancing the sustainability of this growing system. Therefore, the aim of this study was to examine how light segmentation, the incorporation of a low-intensity lighting phase known as the light compensation point (LCP) instead of the traditional dark phase, and variations in the light spectrum impact the agricultural outcomes of organically cultivated leafy greens. In controlled growth chamber environments, a variety of leafy plant species (Spinacia oleracea L., Ocimum basilicum, Beta vulgaris L., Lactuca sativa L. cv. ‘Garrison’ and ‘Blade’, Brassica rapa cv. ‘Japonica’ and ‘Chinensis’, Brassica juncea cv. ‘Scarlet Frills’ and ‘Wasabina’, Eruca sativa and Perilla frutescens L.) were subjected to four light treatments with varying intensities and durations of lighting, while in a second experiment, five different spectral growing conditions were compared. Irrespective of the plant species, shortening the length of the diel cycle by extending the cumulative daily lighting to 20–24 h per day (5L/1N [5 h at 261 µmol m−2 s−1 + 1 h darkness for a total of 20 h of light per day] and 5L/1LCP [5 h at 256 µmol m−2 s−1 + 1 h LCP at 20 µmol m−2 s−1 for a total of 24 h of light per day]) led to an average increase of +12% in height, fresh weight (+16%), dry weight (+23%), and specific leaf weight (+11%), compared to the control plants (18L/6N; 18 h at 289 µmol m−2 s−1 + 6 h darkness) and 6L/6LCP plants (6 h at 418 µmol m−2 s−1 + 6 h LCP at 20 µmol m−2 s−1 for a total of 24 h of light per day) during the first harvest. This also resulted in better light utilization, expressed as increased fresh (+16%) and dry (+24%) biomass per mol of light received. Conversely, the studied light spectral treatments had no effect on the growth parameters of the four selected species. In conclusion, our study showed that reducing light intensity while extending the photoperiod could potentially represent a cost-effective LED strategy for the indoor cultivation of organically or conventionally grown leafy greens. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
17 pages, 1718 KiB  
Article
Effect of Biostimulants on Leafy Vegetables (Baby Leaf Lettuce and Batavia Lettuce) Exposed to Abiotic or Biotic Stress under Two Different Growing Systems
by Justine Clément, Maxime Delisle-Houde, Thi Thuy An Nguyen, Martine Dorais and Russell J. Tweddell
Agronomy 2023, 13(3), 879; https://doi.org/10.3390/agronomy13030879 - 16 Mar 2023
Cited by 6 | Viewed by 3308
Abstract
Plant biostimulants are substances or microorganisms aimed at promoting plant growth by increasing the mineral nutrition efficiency, tolerance to environmental stress, and crop quality traits. This new category of crop inputs has been capturing the interest of both researchers and agriculture takeholders in [...] Read more.
Plant biostimulants are substances or microorganisms aimed at promoting plant growth by increasing the mineral nutrition efficiency, tolerance to environmental stress, and crop quality traits. This new category of crop inputs has been capturing the interest of both researchers and agriculture takeholders in light of the promising effects they could have on crop productivity and sustainability. This study investigated a variety of biostimulants for their effect on germination rates, plant health, chlorophyll fluorescence parameters, SPAD index, and growth of baby leaf lettuce and Batavia lettuce submitted to biotic (absence/presence of Pythium ultimum in the growing medium) or abiotic (0, 40, 80, and 120 mM NaCl L−1 concentrations and −0.5, −2, −4, and −6 kPa water potentials) stresses when grown in a greenhouse under conventional and organic cultivation. The results obtained show that lettuce response to biostimulants was influenced by the type or level of stress applied and the growing system used. The effects of the tested biostimulants varied from strongly detrimental to strongly beneficial. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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19 pages, 2061 KiB  
Article
Evaluation of Copper-Free Alternatives to Control Grey Mould in Organic Mediterranean Greenhouse Tomato Production
by Jose Ignacio Marín-Guirao, Francisco César Páez-Cano, María del Carmen García-García, Nikolaos Katsoulas and Miguel de Cara-García
Agronomy 2023, 13(1), 137; https://doi.org/10.3390/agronomy13010137 - 31 Dec 2022
Cited by 1 | Viewed by 2580
Abstract
Grey mould caused by Botrytis cinerea is an endemic disease in greenhouse tomato crops in the Mediterranean Basin, where the scarcity of heating systems together with the winter weather conditions makes the use of fungicides necessary. The availability of fungicides for organic tomato [...] Read more.
Grey mould caused by Botrytis cinerea is an endemic disease in greenhouse tomato crops in the Mediterranean Basin, where the scarcity of heating systems together with the winter weather conditions makes the use of fungicides necessary. The availability of fungicides for organic tomato production is limited, and traditionally, farmers have used copper-based formulations. In the present work, in vitro tests with twelve commercial formulations resulted in cinnamon extract and potassium hydrogen carbonate (PHC) showing high efficacy in the inhibition of B. cinerea growth. Both formulations were evaluated in on-farm greenhouse trials conducted for two seasons (2019/2020 and 2020/2021) in three greenhouses located in Almería, Spain. In terms of controlling Botrytis, PHC showed efficacy results comparable to or even better than those that have been obtained for copper oxychloride. Weather conditions outside and inside the greenhouse were conducive to the onset and development of the disease. Tomato variety selection and pruning practices (flush cuttings) were the main factors that reduced the use of copper-based formulations or any other fungicide to prevent grey mould infection. Smart and integrated management of the mentioned factors could lead to the substitution of copper to control Botrytis in the crop system studied here. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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19 pages, 816 KiB  
Article
Diet Composition Influences Growth Performance, Bioconversion of Black Soldier Fly Larvae: Agronomic Value and In Vitro Biofungicidal Activity of Derived Frass
by Ghazaleh Arabzadeh, Maxime Delisle-Houde, Russell J. Tweddell, Marie-Hélène Deschamps, Martine Dorais, Yolaine Lebeuf, Nicolas Derome and Grant Vandenberg
Agronomy 2022, 12(8), 1765; https://doi.org/10.3390/agronomy12081765 - 27 Jul 2022
Cited by 33 | Viewed by 6732
Abstract
In recent years, the larval stage of Hermetia illucens, commonly known as the black soldier fly (BSFL), has been used to promote the circularity of the agri-food sector by bioconverting organic waste into larval biomass which has been used as a livestock [...] Read more.
In recent years, the larval stage of Hermetia illucens, commonly known as the black soldier fly (BSFL), has been used to promote the circularity of the agri-food sector by bioconverting organic waste into larval biomass which has been used as a livestock feed. A secondary byproduct of this process is frass that can be used as an organic fertilizer. This study compared two different plant-based diets on frass characteristics as well as larval performance, nutritional composition, and waste reduction efficiency. A fruit/vegetable/bakery waste-based diet supplemented with brewery waste (FVBB) was compared to a control Gainesville (GV) reference diet and fed to BSFL under standard conditions. The results demonstrated that NPK and some of the macro and micronutrients in both frasses are comparable to commercially available organic fertilizers. It was shown that microorganisms present in frass from the two diets inhibit the mycelial growth of several plant pathogens through the production of antifungal and/or anti-oomycetes compound(s) (antibiosis). This diet also had a positive effect on individual larval mass (162.11 mg), bioconversion rate (13.32%), and larval crude lipid (35.99% of dry matter) content. The BSFL reared on this diet reduced feedstock dry matter by 67.76% in a very short time (10 days), which is a promising solution for food waste management. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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15 pages, 3085 KiB  
Article
Drench Application of Soy Protein Hydrolysates Increases Tomato Plant Fitness, Fruit Yield, and Resistance to a Hemibiotrophic Pathogen
by Adam Barrada, Maxime Delisle-Houde, Thi Thuy An Nguyen, Russell J. Tweddell and Martine Dorais
Agronomy 2022, 12(8), 1761; https://doi.org/10.3390/agronomy12081761 - 27 Jul 2022
Cited by 9 | Viewed by 3303
Abstract
At a time when growers have to increase food production, while facing many environmental challenges, biostimulants and plant defence stimulators (PDS) may help reduce the use of chemical fertilizers and pesticides and to promote agriculture that is more respectful of the environment. For [...] Read more.
At a time when growers have to increase food production, while facing many environmental challenges, biostimulants and plant defence stimulators (PDS) may help reduce the use of chemical fertilizers and pesticides and to promote agriculture that is more respectful of the environment. For organic farming, they may contribute to increasing plant resilience and crop productivity. Several studies have shown that plant-derived protein hydrolysates may increase nutrient use efficiency and promote plant resistance to abiotic or biotic stresses. We therefore hypothesized that soy protein hydrolysates increase tomato growth and productivity, while promoting plant disease resistance. Our results showed that one or two drench applications of soy protein hydrolysates (SPH13 and SPH18 at 10 g L−1) to the growing medium increased tomato (‘Micro Tom’) plant growth and fruit production, while one studied hydrolysate enriched in glycine (SPH18) increased the expression levels of PR1 and PR8, two defence-related genes. Although no significant effect was observed on Botrytis cinerea resistance of Micro Tom plants, SPHs significantly increased ‘M82’ plant resistance to foliar inoculation with Pseudomonas syringae pv. tomato DC3000, which further confirmed the systemic activation of plant defence mechanisms by SPHs in tomatoes. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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13 pages, 756 KiB  
Article
Agroecological Screening of Copper Alternatives for the Conservation of Soil Health in Organic Olive Production
by Alev Kir, Barbaros Cetinel, Didar Sevim, Feriste Ozturk Gungor, Francis Rayns, Dionysios Touliatos and Ulrich Schmutz
Agronomy 2022, 12(7), 1712; https://doi.org/10.3390/agronomy12071712 - 20 Jul 2022
Cited by 3 | Viewed by 3137
Abstract
The efficacy of soil conditioner (vermicompost tea), fertiliser (potassium silicate), and biological control agents (BCAs) as practical agroecological copper alternatives against olive leaf spot (Spilocaea oleaginea (Cast.) Hughe.) disease was investigated between 2018 and 2021 under organic management in a Mediterranean [...] Read more.
The efficacy of soil conditioner (vermicompost tea), fertiliser (potassium silicate), and biological control agents (BCAs) as practical agroecological copper alternatives against olive leaf spot (Spilocaea oleaginea (Cast.) Hughe.) disease was investigated between 2018 and 2021 under organic management in a Mediterranean climate. In total, 9 agroecological alternatives to copper oxychloride (vermicompost tea, potassium silicate, Bacillus subtilis EU 007 WP, Platanus orientalis leaf extract, Mycorrhiza mix, seaweed commercial product, Trichoderma citrinoviride TR1, vermicompost tea+Platanus orientalis mix, Penicillium (Mouldy bread pieces)) were applied to olive trees in a randomised block design with 4 replicationsTotal water soluble phenol compounds (TWSP) were found to be the main bioindicator to assess the alternatives and their potential to phase-out copper application. Results related to TWSP indicated that copper oxychloride (control), potassium silicate and vermicompost tea showed significantly higher content of TWSP as we compared zero application of copper and other treatments. These stimulate the antioxidant capacity in olive fruits and reduce the olive leaf spot disease incidence. The pollution effect of copper was monitored during the trial to identify soil pollution in the organic in-conversion experimental land. The total annual ‘active copper’ application was 4.7 kg.ha−1.year−1 and this is in accordance with the legal organic legislation of Turkey. During the conversion period from conventional to organic management, we determined approximately 50% reduced copper content in the soil 0–30 cm depth samples in 2020 (3.70 mg.kg−1) as it is compared to those initial samples (6.43 mg.kg−1) in 2018. We conclude that alternatives to copper that are easily accessible, e.g., vermicompost tea, have a potential for use in organic olive production to replace copper in mitigating olive leaf spots. Furthermore, we find that reduced copper application in organic management with the aim to decrease copper accumulation in soil, fruits and leaves was not yet enough to reduce copper to satisfactory levels. We conclude that further research with the aim of a total replacement of copper fungicide treatments in organic and non-organic systems is needed. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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15 pages, 8892 KiB  
Article
Chlorophyll Fluorescence and Fruit Quality Response of Blueberry to Different Mulches
by Jorge Retamal-Salgado, Beder Loor, Juan Hirzel, María Dolores López, Pablo Undurraga, Nelson Zapata, Rosa Vergara-Retamales and Héctor Olivares-Soto
Agronomy 2022, 12(7), 1702; https://doi.org/10.3390/agronomy12071702 - 19 Jul 2022
Cited by 6 | Viewed by 2071
Abstract
Mulch is widely used in blueberry cultivation for weed control; however, there is still uncertainty as to how the use of different types of mulch alters leaf photosynthetic behavior and the quality and productivity of blueberry fruit. The objective of our research was [...] Read more.
Mulch is widely used in blueberry cultivation for weed control; however, there is still uncertainty as to how the use of different types of mulch alters leaf photosynthetic behavior and the quality and productivity of blueberry fruit. The objective of our research was to evaluate the effect of different types of mulch on the physiological, quality and yield characteristics of blueberries. Three treatments were established: T1 (control), T2 (pine bark) and T3 (geotextile) in two cultivars: Ochlockonee and Legacy. The parameters measured were: the photochemical quantum yield of photosystem II (YII), the maximum photochemical efficiency of photosystem II (Fv/Fm), electron transport rate (ETR), fruit quality and yield parameters. The results show lower soil temperature in T1 during the morning (p < 0.05) compared to the two mulch treatments, which was the opposite during the afternoon, the temperatures were more stable and closer to the optimum (21 °C) in T2 and T3, with mulch favoring root and foliar development. On the other hand, the treatments with mulch favored a higher photosynthetic efficiency of photosystem II (YII) at the end of afternoon and were associated with an increased firmness of the fruit; the firmness of all fruits was higher than that in the control treatment (p < 0.05) in the Legacy cultivar, but without differences between them, with values of 73 and 75 gf mm−1 for T2 and T3, respectively, and 67 gf mm−1 for the Control. In addition, it was observed that the use of mulch only increased the fruit yield in the Legacy cultivar, both in T2 and T3, with both being superior to T1 (p < 0.05). It can be concluded that the use of mulch decreases soil temperature in the midday and late afternoon, improving the edaphoclimatic conditions during the development of the blueberry. In addition, plants with mulch have lower stomatal conductance, which promotes greater photosynthetic efficiency during the day, increasing both firmness and fruit yield. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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19 pages, 2256 KiB  
Article
The Effects of Leguminous Living Mulch Intercropping and Its Growth Management on Organic Cabbage Yield and Biological Nitrogen Fixation
by Sophie Stein, Jens Hartung, Kurt Möller and Sabine Zikeli
Agronomy 2022, 12(5), 1009; https://doi.org/10.3390/agronomy12051009 - 23 Apr 2022
Cited by 5 | Viewed by 3156
Abstract
In organic horticulture, living mulches (LM) are used for weed suppression and erosion prevention. In addition, leguminous LM can contribute to higher nitrogen (N) import into vegetable cultivation systems via biological N2 fixation (BNF). In order to investigate the effect of LM [...] Read more.
In organic horticulture, living mulches (LM) are used for weed suppression and erosion prevention. In addition, leguminous LM can contribute to higher nitrogen (N) import into vegetable cultivation systems via biological N2 fixation (BNF). In order to investigate the effect of LM systems, a two- as well as three-year field experiment was conducted between 2019 and 2021 at two locations in Southwest Germany. White cabbage was intercropped with two different clover varieties (Trifolium repens cv. ‘Rivendel’, with regular growth and T.repens cv. ‘Pipolina’, a micro clover) and perennial ryegrass (Lolium perenne cv. ‘Premium’). Bare soil (with spontaneous vegetation) without intercropping was the control treatment. The second factor was the growth management of the LM: incorporation by rototilling before planting the cabbage, intercropping with the cabbage and no LM growth management, and intercropping with mulching of the LM during the cabbage growing. The results show that rototilling LM before planting the cabbage did not lead to higher weight of cabbage residues or differences in total head yield among the treatments for growth management. Intercropping without further LM growth management did not result in a reduced total head yield of cabbage compared to mulching. The micro clover ‘Pipolina’ showed no reduced competition with cabbage compared to the regular-growing white clover ‘Rivendel’. Therefore, we conclude that leguminous LM systems, regardless of growth management, can achieve high yields with sufficient irrigation and additional fertilization while increasing the inputs of N via BNF into the entire cropping system. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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18 pages, 13738 KiB  
Article
13C Labelling of Litter Added to Tea (Camellia sinensis L.) Plantation Soil Reveals a Significant Positive Priming Effect That Leads to Less Soil Organic Carbon Accumulation
by Xiangde Yang, Kang Ni, Lifeng Ma, Yuanzhi Shi, Xiaoyun Yi, Lingfei Ji and Jianyun Ruan
Agronomy 2022, 12(2), 293; https://doi.org/10.3390/agronomy12020293 - 24 Jan 2022
Cited by 5 | Viewed by 3127
Abstract
Although annual return of litter occurs in tea (Camellia sinensis L.) plantations, the level of soil organic carbon (SOC) therein remains relatively low. The exact impacts of pruned litter on soil and its association with SOC accumulation in tea plantations remain unclear. [...] Read more.
Although annual return of litter occurs in tea (Camellia sinensis L.) plantations, the level of soil organic carbon (SOC) therein remains relatively low. The exact impacts of pruned litter on soil and its association with SOC accumulation in tea plantations remain unclear. In this study, we prepared 13C-labeled tea plant material and incubated it with soils collected at a tea plantation. Carbon dioxide (CO2) efflux and its sources were measured and distinguished based on the 13C isotopic method. Soil microbial community and the utilization of litter C were assessed by phospholipid fatty acid (PLFA) analysis combined with a stable isotope probing (SIP) technique. Litter incorporation initially significantly increased CO2 efflux. The majority of CO2 production (>90%) arose from native SOC mineralization, which was reflected by a strong positive priming effect (PE) that decreased over time. During the incubation period, β-glucosidase activity significantly decreased in both the control and litter-amended soil. A significant difference in the microbial community was observed between control and litter-amended soil, in which litter incorporation significantly increased the biomass of each microbial group relative to control soil. Based on PLFA-SIP, 78% of the C incorporated into individual microbes was derived from native SOC, while only 22% was derived from litter. Additionally, partial least squares regression path modeling (PLS-PM) revealed that the microbes associated with native SOC mineralization directly affected the changes in SOC (ΔCSOC+litter), whereas microbes related to litter degradation exhibited an indirect effect on ΔCSOC+litter by affecting β-glucosidase activity under litter incorporation. Taken together, SOC accumulated less in the tea plantation system despite the annual return of pruned litter to the field. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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13 pages, 2171 KiB  
Article
Estimation of Evapotranspiration and Crop Coefficient of Rain-Fed Tea Plants under a Subtropical Climate
by Shenghong Zheng, Kang Ni, Lingfei Ji, Chenguang Zhao, Hongling Chai, Xiaoyun Yi, Weizhong He and Jianyun Ruan
Agronomy 2021, 11(11), 2332; https://doi.org/10.3390/agronomy11112332 - 18 Nov 2021
Cited by 10 | Viewed by 3112
Abstract
Crop coefficient (Kc) is one of the most significant parameters for crop water demand prediction and irrigation scheduling. However, there is a lack of knowledge about water vapor and Kc in tea plantation ecosystems. This study explored and determined the [...] Read more.
Crop coefficient (Kc) is one of the most significant parameters for crop water demand prediction and irrigation scheduling. However, there is a lack of knowledge about water vapor and Kc in tea plantation ecosystems. This study explored and determined the actual evapotranspiration (ETc) and Kc of two cultivars of tea (Camellia sinensis), clone variety Baiye1 (BY1) and Longjing43 (LJ43), based on lysimeter data. An estimation was made for both for ETc and adjusted ETc, and the corresponding Kc and adjusted Kc. The results showed that the adjusted ETc and Kc values revealed a minor fluctuation when compared to the ETc and Kc values during the experimental period, which indicated that the adjusted ETc and Kc values were more precise and practical to field conditions. The average adjusted Kc values were 0.71 (range of 0.43–1.02) for BY1 and 0.84 (range of 0.48–1.22) for LJ43. Additionally, heavy pruning can decrease ETc and Kc values, possibly due to the lower level of LAI after pruning. Moreover, it is clearly manifested that BY1 consistently had lower ETc and Kc values than those of LJ43 because of plant growth status differences between BY1 and LJ43. Overall, our study proposed a reliable reference of Kc in tea plantation, and illuminated the effects of pruning and plant growth differences on Kc, which could provide a strong basis for precise irrigation in tea plantations in a subtropical climate. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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13 pages, 904 KiB  
Article
Adoption of Conservation Agriculture in Rwanda: A Case Study of Gicumbi District Region
by Yves Theoneste Murindangabo, Marek Kopecký and Petr Konvalina
Agronomy 2021, 11(9), 1732; https://doi.org/10.3390/agronomy11091732 - 29 Aug 2021
Cited by 10 | Viewed by 8209
Abstract
Conservation agriculture (CA) is described as a farming system that is founded around three principles: minimum soil disturbance (reduced or no tillage), keeping a permanent soil cover (with crop residues, cover crops or both) and plant species diversification (plant associations and sequences). Little [...] Read more.
Conservation agriculture (CA) is described as a farming system that is founded around three principles: minimum soil disturbance (reduced or no tillage), keeping a permanent soil cover (with crop residues, cover crops or both) and plant species diversification (plant associations and sequences). Little to no information has been documented about conservation agriculture adoption in developing countries, such as Rwanda, with especially no information about its hilly and climate-varying part to which the Gicumbi district belongs. This study is targeted towards ascertaining the level of CA adoption in the Gicumbi district in relation to the socioeconomic status of the farming population, to suggest the relevant strategies for accelerating CA adoption specific to this region. The sampling technique used was a non-discriminative, snowball-sampling one, eventually gathering data from 500 households in three sectors. Semi-structured interviews were conducted using household questionnaires. Adoption of CA was related to the knowledge acquired during training and hands-on work on demonstration plots. Some farm-level constraints found were little to no material, few extension services and market problems. The impacts attributed to the use of CA were soil and productivity improvement. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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15 pages, 1938 KiB  
Article
The Effect of Mycorrhizal Fungi and PGPR on Tree Nutritional Status and Growth in Organic Apple Production
by Sebastian Przybyłko, Wojciech Kowalczyk and Dariusz Wrona
Agronomy 2021, 11(7), 1402; https://doi.org/10.3390/agronomy11071402 - 13 Jul 2021
Cited by 18 | Viewed by 5259
Abstract
The desire to reduce the negative impact of crops on the environment, as well as the growing concern for consumer health, is increasing interest in organic fruit production. In this context, the development of new environmentally friendly agrotechnical methods which allows for reducing [...] Read more.
The desire to reduce the negative impact of crops on the environment, as well as the growing concern for consumer health, is increasing interest in organic fruit production. In this context, the development of new environmentally friendly agrotechnical methods which allows for reducing the use of organic fertilizers by improving the nutrient use efficiency and consequently decreasing the leaching of them is a task of a great importance. The main purpose of this study was to evaluate the effect of mycorrhizal arbuscular fungi (AMF) combined with plant-growth-promoting rhizobacteria (PGPR) on growth and nutritional status of apple trees cultivated on a silty-loam, rich in clay minerals and humus soil under organic farming conditions. Thus, a trial was established in an experimental orchard in Wilanów in Central Poland with three cultivars (‘Topaz’, ‘Odra’, and ‘Chopin’) and a promising clone, U 8869. Trees were or were not inoculated with AMF + PGPR within a split-block experimental design with four replicates. According to the results, mycorrhizal frequency obtained in the inoculated tree roots was on average two-fold higher than in the roots of the control plants. After four years of AMF + PGPR inoculation, 24% higher trunk cross-section area (TCSA) was observed, with the nitrogen and magnesium concentrations in leaves increasing, on average, by 7.8% and 64.2%, and phosphorus and potassium content decreasing by 37.2% and 46.5%, respectively. This study shows that using AMF + PGPR inoculum supports tree roots colonization by AMF. As a result, better nitrogen nutrition status is observed that promote vigorous growth of trees and more efficient uptake of magnesium from the bulk soil. On the other hand, lower phosphorus content in inoculated tree leaves might be explained by a dilution effect, and potassium decrease could occur as a result of fungus–plant competition in conditions of this element deficiency in soil. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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Review

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26 pages, 994 KiB  
Review
The Impact of Drought Stress on Soil Microbial Community, Enzyme Activities and Plants
by Kalisa Bogati and Maciej Walczak
Agronomy 2022, 12(1), 189; https://doi.org/10.3390/agronomy12010189 - 13 Jan 2022
Cited by 144 | Viewed by 20257
Abstract
Nowadays, the most significant consequence of climate change is drought stress. Drought is one of the important, alarming, and hazardous abiotic stresses responsible for the alterations in soil environment affecting soil organisms, including microorganisms and plants. It alters the activity and functional composition [...] Read more.
Nowadays, the most significant consequence of climate change is drought stress. Drought is one of the important, alarming, and hazardous abiotic stresses responsible for the alterations in soil environment affecting soil organisms, including microorganisms and plants. It alters the activity and functional composition of soil microorganisms that are responsible for crucial ecosystem functions and services. These stress conditions decrease microbial abundance, disturb microbial structure, decline microbial activity, including enzyme production (e.g., such as oxidoreductases, hydrolases, dehydrogenase, catalase, urease, phosphatases, β-glucosidase) and nutrient cycling, leading to a decrease in soil fertility followed by lower plant productivity and loss in economy. Interestingly, the negative effects of drought on soil can be minimized by adding organic substances such as compost, sewage slugs, or municipal solid waste that increases the activity of soil enzymes. Drought directly affects plant morphology, anatomy, physiology, and biochemistry. Its effect on plants can also be observed by changes at the transcriptomic and metabolomic levels. However, in plants, it can be mitigated by rhizosphere microbial communities, especially by plant growth-promoting bacteria (PGPB) and fungi (PGPF) that adapt their structural and functional compositions to water scarcity. This review was undertaken to discuss the impacts of drought stress on soil microbial community abundance, structure and activity, and plant growth and development, including the role of soil microorganisms in this process. Microbial activity in the soil environment was considered in terms of soil enzyme activities, pools, fluxes, and processes of terrestrial carbon (C) and nitrogen (N) cycles. A deep understanding of many aspects is necessary to explore the impacts of these extreme climate change events. We also focus on addressing the possible ways such as genome editing, molecular analysis (metagenomics, transcriptomics, and metabolomics) towards finding better solutions for mitigating drought effects and managing agricultural practices under harsh condition in a profitable manner. Full article
(This article belongs to the Special Issue Agroecology and Organic Horticulture)
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