Organic Horticulture Research Articles

Organic Nitrogen Uptake and Assimilation in Cucumis sativus Using Position-Specific Labeling and Compound-Specific Isotope Analysis.

Organic nitrogen is now considered a significant source of N for plants. Although organic management practices increase soil organic C and N content, the importance of organic N as a source of crop N under organic farming management systems is still poorly understood. While dual-labeled (13C and 15N) molecule methods have been developed to study amino acid uptake by plants, multiple biases may arise from pre-uptake mineralization by microorganisms or post-uptake metabolism by the plant. We propose the combination of different isotopic analysis methods with molecule isotopologues as a novel approach to improve the accuracy of measured amino acid uptake rates in the total N budget of cucumber seedlings and provide a better characterization of post-uptake metabolism. Cucumber seedlings were exposed to solutions containing L-Ala-1-13C,15N or U-L-Ala-13C3,15N, in combination with ammonium nitrate, at total N concentrations ranging from 0 to 15 mM N and at inorganic/organic N ratios from 10:1 to 500:1. Roots and shoots were then subjected to bulk stable isotope analysis (BSIA) by Isotope Ratio Mass Spectrometry (IRMS), and to compound-specific stable isotope analysis (CSIA) of the free amino acids by Gas Chromatography – Combustion – Isotope Ratio Mass Spectrometry (GC-C-IRMS). Plants exposed to a lower inorganic:organic N ratio acquired up to 6.84% of their N from alanine, compared with 0.94% at higher ratio. No 13C from L-Ala-1-13C,15N was found in shoot tissues suggesting that post-uptake metabolism of Ala leads to the loss of the carboxyl-C as CO2. CSIA of the free amino acids in roots confirmed that intact Ala is indeed taken up by the roots, but that it is rapidly metabolized. C atoms other than from the carboxyl group and amino-N from Ala are assimilated in other amino acids, predominantly Glu, Gln, Asp, and Asn. Uptake rates reported by CSIA of the free amino acids are nevertheless much lower (16–64 times) than those reported by BSIA. Combining the use of isotopologues of amino acids with compound-specific isotope analysis helps reduce the bias in the assessment of organic N uptake and improves the understanding of organic N assimilation especially in the context of organic horticulture.

Participatory construction in agroforestry systems in family farming: ways for the agroecological transition in Brazil

ABSTRACTThis article aims to analyze the implementation of Agroforestry Systems (AFS) by family farmers, assessing their contribution to agroecological transition and understanding the process of knowledge construction. The study was carried out in family farming farms in the Sumaré Rural Settlement, and in the area of Family Farming and Agroecological Cooperative (Cooperacra), respectively located in the municipalities of Sumaré and Americana, São Paulo State, Brazil. The methodology was based on a case study, using Focal Groups and Field Notes as research instruments. On the basis of our analysis, there were social changes in the farmers’ organization and in the decision-making process, as well as in the landscape in the areas of AFS and surroundings, where agroecological principles were also applied to production. In Sumaré, the four farmers participating in the project organized themselves to obtain organic certification. Cooperacra, which works with a group of 10 farmers advanced in the process of agroecological transition, starting from an intensive organic horticulture production system to a biodiverse agroforestry system. Despite the short time of the project, the construction of knowledge in relation to agroforestry systems was perceived through management techniques incorporated by the farmers in their agroecosystems. The arboreal component, which thus far the farmers had seen as something to be eliminated to realize agriculture, was introduced and became a relevant part of the process. The results demonstrate the feasibility and potential of AFS in the process of agroecological transition toward a more sustainable agriculture.

Environmental Sustainability Assessment of Horticultural Systems: A Multi-Criteria Evaluation Approach Applied in a Case Study in Mediterranean Conditions

An increasing interest and sensitivity of consumers and public opinion toward high-quality food products obtained with environmentally-friendly production methods has recently been detected. To this end, one of the key roles could be played by an environmental evaluation of the crop production. This research was performed to test a new multi-attribute decision model (DEXi-met) that is able to estimate the environmental sustainability of different agronomic practices in horticultural rotations. The model was used at the cropping system level on the basis of data from a long-term experiment in organic horticulture. It was tested on different cropping managements under climate change conditions. The DEXi-met mixed model (qualitative and qualitative basic attributes) generated four aggregated attributes to assess sustainability indicators (production capacity, soil, water and resources preservation, and biodiversity conservation) and the overall environmental sustainability. The model validation indicated that the introduction of agro-ecological services crops can increase the environmental sustainability of an organic cropping systems by promoting the whole soil–plant system equilibrium. The application of this tool could help maximize the efficient use of agronomical practices and quantify their environmental sustainability. DEXi-met could help agricultural advisors and policymakers schedule their decisions to find the right compromise between crop yield increase and the impact of agricultural activities.

Thigmomorphogenesis – Control of plant growth by mechanical stimulation

Abstract Controlled regulation of plant growth is a general prerequisite for the production of marketable ornamental plants. Consumers as well as retailers prefer stronger, more compact plants with greener leaves as these not only better meet a certain desired visual quality but also allow for a maximization of production per unit area as well as facilitation of packaging and transport. The same applies for the production of young vegetable plants. Special attention is paid to solid, compact and resilient plants that survive transport and planting without any problems. During the last decades plant growth control has mainly been achieved through the application of chemical plant growth regulators that generally interfere with the function of growth regulating hormones. However, there is an increasing demand to replace chemical treatments by other means such as the modulation of growth conditions, including temperature, light and fertilization. Alternatively, the application of mechanical stimulation has been shown to induce plant responses that yield some of the commercially relevant phenotypes including increased compactness, higher girth, darker leaves and a delay in flowering. The ability of plants to sense and respond to mechanical stimuli is an adaptive trait associated with increased fitness in many environmental settings. Mechanical stimulation in nature occurs e.g. through wind, rain, neighboring plants or predatory animals and induces a range of morphogenic responses that have been summarized under the term thigmomorphogenesis. We are only just about to begin to understand the molecular mechanisms underlying mechanosensing and the associated morphogenic changes in plants. However, a number of examples suggest that mechanical stimulation applied in a greenhouse setting can be used to alter plant growth in order to produce marketable plants. In this review will briefly summarize the current knowledge concerning the biological principles of thigmomorphogenesis and discuss the potential of mechanical growth regulation in commercial plant production especially with respect to organic horticulture.

Organik Bahçe Ürünlerinin Hasat Sonrası Kalitelerinin Korunması

Not only cultural treatments in orchard but also postharvest handling affect the taste, shelf life and nutritional quality of organic fruits and vegetables. Organic crops are mostly harvested at ripe stage or close to ripen, thus, their shelf life is shorter and they are more perishable. Postharvest physiology and requests of crops should be considered during postharvest handling in order to maintain their high quality and prevent postharvest losses. The main aim in postharvest concept is to slow down the metabolism of fresh crops continue to live after harvest. The most important factor is temperature. The fruits and vegetables should be protected from high temperatures and cooled immediately after harvest. The cold chain should be kept until consumer. In addition, diseases can be prevented by controlling environment. Sanitation is another rule to consider. All these rules are important for all growers; however they are of special importance for organic horticulture which allows limited postharvest technologies. In this review, the allowed postharvest treatments of certificated organic fruits and vegetables are given. Preharvest factors, harvest, postharvest factors, cooling methods, cold storage, sanitation methods and products, ethylene and its control, and other specific postharvest subjects are discussed.

Effects of plant extracts and sodium hypochlorite on lettuce germination and inhibition of Cercospora longissima in vitro

Abstract Vegetables that are propagated by seeds are considered to be commercially and nutritionally valuable. However, there is a need to overcome the present challenge of developing alternative technologies for organic horticulture. This paper evaluates the potential use of the aqueous extracts of clove, cinnamon, and coriander and the sodium hypochlorite in the germination of lettuce (Lactuca sativa) seeds and in the control of Cercospora disease. Two experimental groups were thus designed: 1) the effects of the different aqueous extracts on germination and initial development of lettuce seeds were observed and; 2) the effects of these extracts on the mycelial growth of the fungus Cercospora longissima (isolated from lettuce plants) were evaluated. The treatments used in the first group were control (with water only), 5% (v/v) sodium hypochlorite (NaOCl) and 5% (w/v) aqueous extracts of clove, cinnamon, and coriander. The pretreatment of seeds was performed just before placing them for germination by immersing in these solutions. In the second set of the experiment, the inhibition of mycelial growth of the Cercospora longissima, isolated from lettuce plants presenting cercosporiosis symptoms, was evaluated. In the seeds treated with clove and cinnamon extracts, the germination speed index was negatively affected, while those treated with coriander extract showed an increase in the fresh mass of the aerial part and in the number of leaves of lettuce seedlings. In the second experimental group, it was observed that the growth of Cercospora longissima was inhibited completely by the cinnamon extract and by sodium hypochlorite.

School of A

School of A

Sikkim organic horticulture: Scope, challenges and prospects

Sikkim lies in the eastern Himalayas between 27° to 28° North latitude and 88° to 89° east longitudes. Its North border is connecting with the vast stretch of tibetan Plateau, Nepal in the west, Bhutan and Chumbi valley of tibet in the east and Darjeeling District of west Bengal in the South. Sikkim climate varies from the Sub-tropical to the Alpine depending upon the altitude. the populace of Sikkim comprises of 14 hill tribes and many plainsmen communities. According to FIBL & IFoAM year Book 2018, India's rank 9th in terms of world's organic Agricultural land and 1st in terms of total number of producers. During 2017–18, India produced around 1.70 million MT of certified organic products which includes all varieties of food products. Sikkim has distinct advantages of continuing traditional farming and farmers have certain level of knowledge and skills for organic farming. the state possesses range of agro-climatic conditions and unique commodities indigenous to the farming viz., large cardamom, red cherry pepper, cymbidium orchids, ginger, Sikkim mandarin etc. Farmers prefer traditional varieties of crops as these are adapted to the region and superior in quality and taste. The crops are grown mostly in traditional way but farmers are now adopting improved technologies in organic farming system and thus adding value to the crops which hold the promise to become niche commodities for national and international markets.

Iain Tolhurst , Back to Earth: UK Organic Horticulture Through the Lifetime of a Grower. Whitchurch-on-Thames, Tolhurst Organic Partnership, 2016. 278 pp. £24.99. 9789975871075 hbk.

Iain Tolhurst , Back to Earth: UK Organic Horticulture Through the Lifetime of a Grower. Whitchurch-on-Thames, Tolhurst Organic Partnership, 2016. 278 pp. £24.99. 9789975871075 hbk. - Volume 28 Issue 2

Lower average yields but similar yield variability in organic versus conventional horticulture. A meta-analysis

Organic agriculture prohibits the use of almost all synthetic inputs and it is expected to have lower impacts on natural resources than conventional agriculture. However, previous meta-analyses have shown that yields in organic systems are in average 8 to 25% lower compared with conventional systems. Here, we focus on horticulture (fruits and vegetables) and we refine our knowledge by characterising the distributions of organic and conventional yields both in terms of average yield loss and in terms of variability across experiments and across years. We built a new dataset including 636 ratios of organic versus conventional yields covering 37 horticultural species and 17 countries and estimated (i) mean yield ratios, (ii) yield ratio probability distribution across experiments and (iii) interannual yield variances in organic and conventional systems. Our results show that yields in organic horticulture are indeed on average 10 to 32% lower than those in conventional horticulture but they exhibit large variation across experiments. An analysis of yield ratio probability distribution shows that yield loss in organic horticulture has about 10% chances to exceed 50% compared to conventional systems. The analysis gives also around 20% chances to get higher yields in organic horticulture compared to conventional systems. None of the tested covariates (e.g. crop type, climate zone) was able to explain a significant part of the yield ratio variability. We find no evidence of a larger interannual variability (i.e. lower yield stability) in organic versus conventional horticulture. Longer-term trials could nonetheless help substantiate this result. Our results support also the needs to conduct new experiments in countries from the Southern Hemisphere and to collect standard data on crop management and environmental characteristics.

Vision of COST BioGreenhouse

Good food is the basis of a healthy, active life. Horticulture provides fresh commodities rich in minerals, fibres and bioactive compounds, and thereby contributes to a healthy diet. Integrated and organic horticultural production, either indoors or outdoors, contribute to food provisioning. For food and nutrition security, food must be: 1) present in sufficient quantities, 2) physically, economically and socially accessible and affordable, 3) nutritious, with a quality that meets dietary needs and preferences, 4) safe and 5) supported by an adequate environment regarding sanitation, health service and care. To pursue the ambition of developing organic horticulture in greenhouses and high tunnels into an active player within the food system and foodservice, a shift in paradigm is needed - organic protected horticulture needs to redefine itself from being a resource provider/supplier, mainly focusing on production systems and environment, to being an active player in the arena of grand global challenges and human health-integrating societal aspects, e.g., well-being. Organic greenhouse horticulture not only addresses, but also delivers, key solutions in some areas of conflicts, such as land, water and energy use and recycling of resources. In addition, it offers opportunities for empowerment of rural and urban areas. Most research on organic horticulture considers organic greenhouse production systems and production environments. The BioGreenhouse vision considers interactivities between the environmental and societal sphere of food. Innovative organic approaches are a critical precondition for improvement. The potential of organic greenhouse horticulture needs to be brought to the awareness of policy makers. Research to explore the multilevel and multidisciplinary as well as multistakeholder interactions of organic production in greenhouses and high tunnels must be encouraged, by all necessary means.

Organic seed treatments of vegetables to prevent seedborne diseases

Seedborne pathogens of vegetables are responsible for the re-emergence of diseases of the past, as well as the introduction of diseases into new geographical areas. Seed treatment can be used to eradicate seedborne pathogens or to protect from soilborne pathogens. The European Commission Regulation (EC) No. 1452/ 2003 states that only organic seeds must be used in organic horticulture. Starting crop production with clean seeds is the background for a healthy crop. Physical seed treatments, including mechanical treatments, thermal treatments, radiations, and redox treatments can be highly effective. The use of natural compounds, which could be of organic or inorganic nature, is another useful tool. Organic compounds comprise plant extracts, essential oils, as well as purified microorganism compounds. Biological control, based on the use of antagonistic microorganisms, can be effective and sustainable to control seedborne diseases. Indigenous or introduced seed-associated microorganisms might suppress seed infections by pathogens. Numerous filamentous fungi, yeast, and bacteria have been studied as biological control agents against seedborne pathogens. Microbial interactions on the spermosphere should be deeply investigated in order to develop effective BCAs. Seed treatments with elicitors may be helpful to initiate a defence response already early in plant development and has the advantage of being applied in a contained environment. The main advantages and drawbacks for every type of seed treatment will be described, together with the main knowledge and technology gaps concerning vegetable crops. The cost-effectiveness of the seed treatments will be considered. Integrated control strategies, including different seed treatments, could be helpful to guarantee a high level of disease Control and production yield.

Irrigation management in organic greenhouse: how to comply with sustainability goals

Irrigation in protected cultivation is essential due to the absence of natural precipitation. High evapotranspiration, due to higher temperature and prolonged cropping period, requires ample an adequate supply of water. The water supply in a greenhouse is solely carried out by irrigation and thus enables full control over the water management of the greenhouse soil. There are no specific prescriptions for organic greenhouse horticulture (OGH) regarding water sources or irrigation. However, according to the basic principles, growers are obliged to responsibly use natural resources such as water. Thus, efficient water use and/or water recycling are important issues for organic farming. Salinity should be avoided through proper fertilisation management and the use of water sources of adequate quality. Moreover, rainwater collection is strongly encouraged or requested for operation sites situated in climatic suitable areas. Optimal and tuned irrigation is quite challenging for OGH. Obviously, supplying the crop with sufficient water is an important precondition for optimum crop health and performance. In addition, sufficient soil moisture is required for optimal functioning of the soil biota to secure mineral delivery from the applied organic amendments. Also accumulation of undesired salts must be avoided. On the other hand, nutrient leaching should be avoided or limited to a minimum. The irrigation management should take heterogeneities due to irregular water delivery of the irrigation system as well as site variations in soil and plants into account Minimizing leaching should be one of the main drivers for optimization of irrigation in OGH. Since OGH in Europe are strictly soil bound cultures, leaching and nutrient emission to groundwater is a threat. For soils with groundwater within reach of the root zone, capillary rise may add to the water supply of crops. However, irrigation strategies aiming at deficit irrigation, in other words, relying on capillary rise, can be used for the short term only. Given the presence of a surplus of ions in groundwater not only salts like Na and Cl, but also Ca, Mg, SO4 and even K, salinity problems will occur on the long run. Irrigation management tuned to crop requirements is an important issue for sustainable organic greenhouse production. To achieve sustainable management of OGH production, irrigation should be tuned to the demand of the crop, taking into account also the variations in climatic zones, soil types, growing seasons, planting dates and cultivars. Consequently, tools are required for irrigation management with the flexibility to deal with such variation. This paper will review the important aspects of the crop water demand and tools for irrigation management in organic greenhouse vegetables.

Disease management in organic greenhouse horticulture: solutions, new insights and bottlenecks

Disease management in organic greenhouse horticulture: solutions, new insights and bottlenecks

Pest management in organic greenhouse horticulture

The management of pests is one of the major challenges in organic greenhouse cropping systems. In this paper, I summarize the currently most problematic and persistent, as well as the newly emerging pest species in organic tomato, sweet pepper, cucumber and aubergine crops in Europe. Furthermore, I discuss 3 new developments in biological pest control with arthropod natural enemies: 1) the integration of augmentative and conservation biological control, 2) the increased use of omnivorous predators as biological control agents and 3) the presence of other factors that affect directly or indirectly the performance of pests and natural enemies, such as endophytes, plant nutrition, disease control and greenhouse climate management. Finally, I suggest some directions for future research.

Comparing the usefulness of assessment tools for environmental impacts evaluation of organic greenhouse horticulture

Comparing the usefulness of assessment tools for environmental impacts evaluation of organic greenhouse horticulture

Vegan organic horticulture – standards, challenges, socio-economics and impact on global food security

Vegan organic horticulture – standards, challenges, socio-economics and impact on global food security

Establishment of intercropping of beet and chicory depending on soil management

This study aimed to evaluate the productivity and quality characteristics of beet and chicory based on management of straw and intercropping period of establishment. The experiment was conducted in the organic horticulture sector of UNIOESTE, in a design of randomized blocks with four replications, where the treatments were arranged in 2 x 5 and 2 x 8 factorial schemes. The first factorial consisted of the straw mulch management (with and without incorporation of the gray velvet bean straw) and the intercropping period of establishments and beet and chicory monocrops (0; 7; 14 and 21 days after transplanting beet). The second factorial was composed of the straw mulch management (with and without incorporation) and the cultivation of chicory intercropped with beet and in monocrop at the same periods. The chicory interfered in beet’s productivity when the transplant occurred at the same period. The beet cultivation in a intercropping contributed positively to the better use of the area in the two management systems, influencing in a positive way the agronomic characteristics of the crop, but without compromising the commercial quality of the crops, that were agronomically viable, considering the UET index.

Networks for a competitive and innovative organic horticulture in Flanders

Networks are considered to gain potential for supporting innovation. To understand how networks can maximally support the grower’s innovation process, a conceptual framework was constructed based on five dimensions: (i) creative idea generation, (ii) knowledge assemblage, (iii) learning process, (iv) coalition building and (v) institutional innovation. This paper explores how recently established networks for creating and exchanging knowledge in organic horticulture in Flanders can contribute to the innovation capacity of the organic horticultural community. Our analysis shows that each network has its rationality and assists its members, the organic grower and the organic sector as a whole, directly or indirectly, during their innovation process. The individual potential of the networks is highly reinforced by their close cooperation and safeguards the coherence of decisions taken in the networks. Individual networks are allowed to focus on their core usiness, but by aligning their activities they become more efficient and effective participants in the organic food and farming knowledge system. The actors and the governance of the networks, besides the creation of trust, the recognition of similar innovation models and necessary institutional support are seen as crucial in the success of the networks.

Bioherbicides in Organic Horticulture

Organic horticulture producers rank weeds as one of their most troublesome, time-consuming, and costly production problems. With the increasing significance of organic horticulture, the need for new bioherbicides to control weeds has grown. Potential bioherbicides may be developed from pathogens, natural products, and extracts of natural materials. Fungal and bacteria pathogens are two important types of microbial agents that have potential to be used as bioherbicides. The byproducts of natural sources such as dried distillers grains with solubles (DDGS), corn gluten meal (CGM), and mustard seed meals (MSMs) have shown herbicidal activities in controlling many weed species. Some essential oil extracts have shown bioherbicide potential as well. The efficacy of a bioherbicide is the main limiting factor for its application, and it may be affected by environmental factors such as humidity and moisture, the application method, the spectrum of the bioherbicide, and the type of formulation. In addition to efficacy, costs and concerns about potential human health threats are also limitations to bioherbicide use. As the integration of bioherbicide technology into current weed management systems may help manage herbicide resistance, reduce production costs, and increase crop yields, future research should involve the development of more cost-effective and efficient bioherbicides for control of weeds, as well as the optimization of production methods and cultural practices with use of candidate bioherbicides.