Showing papers in "Horticulturae in 2017"

Soil Salinity: Effect on Vegetable Crop Growth. Management Practices to Prevent and Mitigate Soil Salinization

Abstract: Salinity is a major problem affecting crop production all over the world: 20% of cultivated land in the world, and 33% of irrigated land, are salt-affected and degraded. This process can be accentuated by climate change, excessive use of groundwater (mainly if close to the sea), increasing use of low-quality water in irrigation, and massive introduction of irrigation associated with intensive farming. Excessive soil salinity reduces the productivity of many agricultural crops, including most vegetables, which are particularly sensitive throughout the ontogeny of the plant. The salinity threshold (ECt) of the majority of vegetable crops is low (ranging from 1 to 2.5 dS m−1 in saturated soil extracts) and vegetable salt tolerance decreases when saline water is used for irrigation. The objective of this review is to discuss the effects of salinity on vegetable growth and how management practices (irrigation, drainage, and fertilization) can prevent soil and water salinization and mitigate the adverse effects of salinity.

Effects of Light Quality on Growth and Phytonutrient Accumulation of Herbs under Controlled Environments

Abstract: In recent years, consumption of herb products has increased in daily diets, contributing to the prevention of cardiovascular diseases, chronic diseases, and certain types of cancer owing to high concentrations of phytonutrients such as essential oils and phenolic compounds To meet the increasing demand for high quality herbs, controlled environment agriculture is an alternative and a supplement to field production Light is one of the most important environmental factors influencing herb quality including phytonutrient content, in addition to effects on growth and development The recent development and adoption of light-emitting diodes provides opportunities for targeted regulation of growth and phytonutrient accumulation by herbs to optimize productivity and quality under controlled environments For most herb species, red light supplemented with blue light significantly increased plant yield However, plant yield decreased when the blue light proportion (BP) reached a threshold, which varied among species Research has also shown that red, blue, and ultraviolet (UV) light enhanced the concentration of essential oils and phenolic compounds in various herbs and improved antioxidant capacities of herbs compared with white light or sunlight, yet these improvement effects varied among species, compounds, and light treatments In addition to red and blue light, other light spectra within the photosynthetically active region—such as cyan, green, yellow, orange, and far-red light—are absorbed by photosynthetic pigments and utilized in leaves However, only a few selected ranges of light spectra have been investigated, and the effects of light quality (spectrum distribution of light sources) on herb production are not fully understood This paper reviews how light quality affected the growth and phytonutrient accumulation of both culinary and medicinal herbs under controlled environments, and discusses future research opportunities to produce high quantity and quality herbs

Plant-Based Methods for Irrigation Scheduling of Woody Crops

Abstract: The increasing world population and expected climate scenarios impel the agricultural sector towards a more efficient use of water. The scientific community is responding to that challenge by developing a variety of methods and technologies to increase crop water productivity. Precision irrigation is intended to achieve that purpose, through the wise choice of the irrigation system, the irrigation strategy, the method to schedule irrigation, and the production target. In this review, the relevance of precision irrigation for a rational use of water in agriculture, and methods related to the use of plant-based measurements for both the assessment of plant water stress and irrigation scheduling, are considered. These include non-automated, conventional methods based on manual records of plant water status and gas exchange, and automated methods where the related variable is recorded continuously and automatically. Thus, the use of methodologies based on the Scholander chamber and portable gas analysers, as well as those of systems for measuring sap flow, stem diameter variation and leaf turgor pressure, are reviewed. Other methods less used but with a potential to improve irrigation are also considered. These include those based on measurements related to the stem and leaf water content, and to changes in electrical potential within the plant. The use of measurements related to canopy temperature, both for direct assessment of water stress and for defining zones with different irrigation requirements, is also addressed. Finally, the importance of choosing the production target wisely, and the need for economic analyses to obtain maximum benefit of the technology related to precision irrigation, are outlined.

Agronomic Management for Enhancing Plant Tolerance to Abiotic Stresses—Drought, Salinity, Hypoxia, and Lodging

Abstract: Abiotic stresses are currently responsible for significant losses in quantity and reduction in quality of global crop productions. In consequence, resilience against such stresses is one of the key aims of farmers and is attained by adopting both suitable genotypes and management practices. This latter aspect was reviewed from an agronomic point of view, taking into account stresses due to drought, water excess, salinity, and lodging. For example, drought tolerance may be enhanced by using lower plant density, anticipating the sowing or transplant as much as possible, using grafting with tolerant rootstocks, and optimizing the control of weeds. Water excess or hypoxic conditions during winter and spring can be treated with nitrate fertilizers, which increase survival rate. Salinity stress of sensitive crops may be alleviated by maintaining water content close to the field capacity by frequent and low-volume irrigation. Lodging can be prevented by installing shelterbelts against dominant winds, adopting equilibrated nitrogen fertilization, choosing a suitable plant density, and optimizing the management of pests and biotic diseases harmful to the stability and mechanic resistance of stems and roots.

Remote Sensing for Irrigation of Horticultural Crops

Abstract: This paper reviews the literature on applications of remote sensing for monitoring soil- and crop- water status for irrigation purposes. The review is organized into two main sections: (1) sensors and platforms applied to irrigation studies and (2) remote sensing approaches for precision irrigation to estimate crop water status, evapotranspiration, infrared thermography, soil and crop characteristics methods. Recent literature reports several remote sensing (RS) approaches to monitor crop water status in the cultivated environment. Establishing the right amount of water to supply for different irrigation strategies (maximization of yield or water use efficiency (WUE)) for a large number of crops is a problem that remains unresolved. For each crop, it will be necessary to create a stronger connection between crop-water status and crop yield.

Improving Plant Water Use Efficiency through Molecular Genetics

Abstract: Improving crop performance under water-limiting conditions is essential for achieving environmentally sustainable food production. This requires significant progress in both the identification and characterization of key genetic and physiological processes involved in water uptake and loss. Plants regulate water uptake and loss through both developmental and environmental responses. These responses include: root morphology and architecture, cuticle development, stomatal development, and guard cell movements in response to the environment. Genes controlling root traits and stomatal development and guard cell movements strongly impact water use efficiency (WUE), and represent the best targets for molecular breeding programs. This article provides an overview of the complex networks of genes involved in water uptake and loss. These traits represent novel opportunities and strategies for genetic improvement of WUE and drought tolerance in crops.

New Trends in the Fertigation Management of Irrigated Vegetable Crops

Abstract: The use of fertigation, coupled with micro-irrigation, has continued to increase since it was first introduced in horticultural cropping systems. This combination provides a technical solution whereby nutrients and water can be supplied to the crop with high precision in terms of time and space, thereby allowing high nutrient use efficiency. However, the correct estimation of crop nutrient and water needs is fundamental to obtaining precise plant nutrition and high nutrient use efficiency in fertigated cropping systems. This paper illustrates the state-of-the-art and new perspectives for optimal nutrient management of vegetable crops cultivated under fertigation regimes. An overall description is reported for the most valuable technologies and techniques based on simulation models, soil testing, plant testing, and related decision support systems that can be adopted for efficient fertigation. However, it should be highlighted that only a few of the above technologies and techniques are practically available and/or easy to use by growers. Therefore, much more attention should be paid in the future to the transfer of research knowledge to farmers and technical advisors.

New Approaches to Irrigation Scheduling of Vegetables

Abstract: Using evapotranspiration (ET) data for scheduling irrigations on vegetable farms is challenging due to imprecise crop coefficients, time consuming computations, and the need to simultaneously manage many fields. Meanwhile, the adoption of soil moisture monitoring in vegetables has historically been limited by sensor accuracy and cost, as well as labor required for installation, removal, and collection of readings. With recent improvements in sensor technology, public weather-station networks, satellite and aerial imaging, wireless communications, and cloud computing, many of the difficulties in using ET data and soil moisture sensors for irrigation scheduling of vegetables can now be addressed. Web and smartphone applications have been developed that automate many of the calculations involved in ET-based irrigation scheduling. Soil moisture sensor data can be collected through wireless networks and accessed using web browser or smartphone apps. Energy balance methods of crop ET estimation, such as eddy covariance and Bowen ratio, provide research options for further developing and evaluating crop coefficient guidelines of vegetables, while recent advancements in surface renewal instrumentation have led to a relatively low-cost tool for monitoring crop water requirement in commercial farms. Remote sensing of crops using satellite, manned aircraft, and UAV platforms may also provide useful tools for vegetable growers to evaluate crop development, plant stress, water consumption, and irrigation system performance.

Nitrogen Related Diffuse Pollution from Horticulture Production—Mitigation Practices and Assessment Strategies

Abstract: Agriculture is considered one of the main nitrogen (N) pollution sources through the diffuse emissions of ammonia (NH3) and nitrous oxide (N2O) to the atmosphere and nitrate (NO3−) to water bodies. The risk is particularly high in horticultural production systems (HPS), where the use of water and fertilizers is intensive and concentrated in space and time, and more specifically, in the case of vegetable crops that have high growth rates, demanding an abundant supply of water and nitrogen forms. Therefore, to comply with the EU environmental policies aimed at reducing diffuse pollution in agriculture, there is the need for mitigation practices or strategies acting at different levels such as the source, the timing and the transport of N. HPS are often well suited for improvement practices, but efficient and specific tools capable of describing and quantifying N losses for these particular production systems are required. The most common mitigation strategies found in the literature relate to crop, irrigation and fertilization management. Nevertheless, only the success of a mitigation strategy under specific conditions will allow its implementation to be increasingly targeted and more cost effective. Assessment methods are therefore required to evaluate and to quantify the impact of mitigation strategies in HPS and to select the most promising ones.

Quantifying Postharvest Loss and the Implication of Market-Based Decisions: A Case Study of Two Commercial Domestic Tomato Supply Chains in Queensland, Australia

Abstract: Using a multi-disciplinary approach, this study quantifies horticultural postharvest losses of two medium-sized (annual pack volume 4500 t) commercial, domestic, tomato supply chains. Quantification of loss was based on weight or volume, consistent with direct measurement methods of the Food Loss and Waste Accounting and Reporting Standard 2016 and qualitative techniques were used to identify the drivers of the loss and contextualise the findings. Postharvest loss was found to be between 40.3% (55.34 t) and 55.9% (29.61 t) of the total harvestable product. It was determined that between 68.6% and 86.7% of undamaged, edible, harvested tomatoes were rejected as outgrades and consequently discarded due to product specifications. Between 71.2% and 84.1% of produced tomatoes were left in the field and not harvested. This study highlights significant factors contributing to high levels of food loss and waste. Edible products are being removed from the commercial food supply chain, rejected as outgrades deemed cosmetically defective due to market-based decisions. With only 44.1% and 59.7% of the harvestable crop reaching the consumers of the two supply chains, respectively, it is perhaps more appropriate to describe a food “waste” chain as opposed to a food “supply” chain.

Plant Water Status Indicators for Irrigation Scheduling Associated with Iso- and Anisohydric Behavior: Vine and Plum Trees

Abstract: Plant water status indicators have been increasingly used for scheduling irrigation. Different variables may be used to do this, depending on personal preferences and the resources available. Many studies have suggested that selection of an indicator should take into account plant behavior in relation to isohydricity. In two Iberian studies, deficit irrigation (DI) was applied in a vineyard and in a plum orchard while plant water status and fluxes were monitored. These case-studies are discussed with special focus on the use of predawn leaf water potential (Ψpd) versus stem water potential (Ψst) to determine whether Ψst performed better and would therefore be the preferred stress indicator for plants exhibiting anisohydric behavior. In contrast, in plants with isohydric behavior, Ψpd would be generally preferred. This hypothesis seems to be supported by the present results obtained and by prior studies. The cultivars used and the intensity of stress applied have an important influence on the results. This suggests that, if no specific information is available from the existing literature, daily preliminary studies would be recommended prior to application in order to select the most appropriate plant water stress indicators.

Stress Coefficients for Soil Water Balance Combined with Water Stress Indicators for Irrigation Scheduling of Woody Crops

Abstract: There are several causes for the failure of empirical models to estimate soil water depletion and to calculate irrigation depths, and the problem is particularly critical in tall, uneven, deficit irrigated (DI) crops in Mediterranean climates. Locally measured indicators that quantify water status are useful for addressing those causes and providing feed-back information for improving the adequacy of simple models. Because of their high aerodynamic resistance, the canopy conductance of woody crops is an important factor in determining evapotranspiration (ET), and accurate stress coefficient (Ks) values are needed to quantify the impact of stomatal closure on ET. A brief overview of basic general principles for irrigation scheduling is presented with emphasis on DI applications that require Ks modelling. The limitations of existing technology related to scheduling of woody crops are discussed, including the shortcomings of plant-based approaches. In relation to soil water deficit and/or predawn leaf water potential, several woody crop Ks functions are presented in a secondary analysis. Whenever the total and readily available water data were available, a simple Ks model was tested. The ultimate aim of this discussion is to illustrate the central concept: that a combination of simple ET models and water stress indicators is required for scheduling irrigation of deep-rooted woody crops.

Shelf Life of Tropical Canarium Nut Stored under Ambient Conditions

Abstract: There is a need to develop alternative crops to improve the food security and prosperity of developing countries. The tropical nut Canarium indicum (canarium nut) is increasingly used as a shade tree for cocoa and has potential for commercialization as a sustainable crop that will improve food security and livelihoods in Melanesia and East Asia. There is no information on canarium nut shelf life characteristics. Canarium kernels may be prone to rancidity, due to a high content of unsaturated fatty acids. Kernels at 5.4% moisture content were vacuum-packed with a domestic vacuum-packaging system and stored for six months in Papua New Guinea and for nine months in Southeast Queensland, Australia at both ambient temperatures (22 to 31 °C and 22 to 25 °C, respectively) and under refrigeration. Nuts were analysed for changes in peroxide values and free fatty acids (FFAs) over the storage periods that might indicate development of rancidity. Peroxide values indicated very low levels of oxidation in all treatments. Free fatty acids were at low levels but increased significantly during storage at ambient temperatures. The results suggested that vacuum-packed Canarium nuts can be stored safely under ambient tropical conditions for six months with daytime temperatures around 31 °C, and for nine months at 25 °C. Increasing FFA levels at ambient temperatures indicate caution about longer storage time at ambient temperatures. Storage under refrigeration greatly prolonged shelf life.

Growth and Tissue Elemental Composition Response of Butterhead Lettuce (Lactuca sativa, cv. Flandria) to Hydroponic Conditions at Different pH and Alkalinity

Abstract: Biomass and tissue elemental differences were quantified for lettuce grown in deep-water conventional hydroponic conditions at two pH and alkalinity conditions. Nutrient solutions were created using inorganic salts and either reverse osmosis (RO) water or municipal water with high alkalinity. Three treatments were evaluated: (a) nutrient solution created with reverse osmosis (RO) water and maintained at pH 5.8 (H5); (b) same as H5 but maintained at pH 7.0 (H7); and (c) nutrient solution created using municipal water and maintained at pH 7.0, referred to as HA7. Averaged across three trials, the HA7 and H7 treatments produced 26% less shoot fresh weight (FW) than the H5 treatment with an 18% reduction in dry weight (DW). The H5 treatment had the least biomass in root FW and DW. In tissue elemental analyses, both the pH 7.0 treatments showed lower concentrations than H5 in Cu, N, Mo, and Sr, and increased concentrations in Ba, Mg, Na, and Zn. There were no differences in Al, C, Ca, Fe, K, Mn, Ni, P, S, and Si concentrations among treatments (p = 0.05). The results from this experiment can be used to isolate the effects of pH and alkalinity in aquaponic conditions where pH and alkalinity will mimic HA7 conditions.

Climate Change Impacts on Water Use in Horticulture

Abstract: The evidence for anthropogenic global climate change is strong, and the projected climate changes could greatly impact horticultural production. For horticulture, two of the biggest concerns are related to the scarcity of water for crop production and the potential for increased evapotranspiration (ET). While ET is known to increase with air temperature, it is also known to decrease with increasing humidity and atmospheric CO2 concentration. Considering all of these factors and a plausible climate projection, this paper demonstrates that ET may increase or decrease depending on the magnitude of atmospheric changes including wind speed. On the other hand, the evidence is still strong that water resources will become less reliable in many regions where horticultural crops are grown.

Aquaponics in Urban Agriculture: Social Acceptance and Urban Food Planning

Abstract: Aquaponics is emerging as a novel technology with particular potential for urban agriculture (UA). The social acceptance of aquaponics and its place in urban food planning has not previously been studied. This study used focus groups, key informant interviews, and scenario analyses to investigate the reactions of Adelaide’s urban food opinion leaders and local government area (LGA) officials to aquaponics. Most of the focus group participants were unfamiliar with aquaponics. The perceived negatives of the technology received greater attention than the perceived benefits. Aquaponics was thought to be most competitive in either niche or wholesale markets, with a need for scaled guidelines from backyard to large-scale commercial production. For aquaponics in urban settings the influence of urban planning and policy is an important, but to date unstudied, consideration. The urban growers’ opinions of the overcomplicated nature of urban food planning corresponded with the mixed policy responses of the LGAs towards UA. This further supports the participants’ desire for a supportive State Government stance on UA to encourage consistency in LGAs.

Response of Eustoma Leaf Phenotype and Photosynthetic Performance to LED Light Quality

Abstract: In a controlled environment, light from light-emitting diodes (LEDs) has been associated with affecting the leaf characteristics of Eustoma. LEDs help plant growth and development, yet little is known about photosynthetic performance and related anatomical features in the early growth stage of Eustoma leaves. In this study, we examined the effects of blue (B), red (R), and white (W) LEDs on the photosynthetic performance of Eustoma leaves, as well as leaf morphology and anatomy including epidermal layer thickness, palisade cells, and stomatal characteristics. Leaves grown under B LEDs were thicker and had a higher chlorophyll content than those grown under the R and W LEDs. Leaves under B LEDs had greater net photosynthetic rates (A), stomatal conductance (gs), and transpiration rates (E), especially at a higher photon flux density (PPFD), that resulted in a decrease in the intercellular CO2 concentration (Ci), than leaves under the W and R LEDs. B LEDs resulted in greater abaxial epidermal layer thickness and palisade cell length and width than the R and W LED treatments. The palisade cells also developed a more cylindrical shape in response to the B LEDs. B LED leaves also showed greater guard cell length, breadth, and area, and stomatal density, than W or R LEDs, which may contribute to increased A, gs and E at higher PPFDs.

Yield Performance of Organic Sweetpotato Varieties in Various Mulches

Abstract: Interest in organic sweetpotato production in the United States has been growing as consumers and producers are becoming increasingly concerned about how their food is cultivated. Thus, there is a growing need for information on sweetpotato production and variety selection under an organic management production system. The objective of this study was to evaluate the effects of various mulches on yields—total and marketable—of fourteen sweetpotato varieties grown under organic management. Three types of mulch, wheat straw, pine needle, and black plastic, and a control (no mulch) were evaluated during the 2016 growing season. The wheat straw mulch yielded significantly higher yields than the black plastic and pine needle mulch treatments, though it was not significantly different from the control. The total and marketable yields of sweetpotato roots also varied significantly among the varieties, ranging from 39,719 kg·ha−1 for Beauregard to 4925 kg·ha−1 for O’Henry. There was a significant interaction between variety and mulch treatment on total but not marketable yield. More research is needed to ascertain the stability of the effects of varieties, mulch treatment, and their interactions on total and marketable yields and to elucidate other treatments and varieties with better potential to improve sweetpotato yields in organically managed production systems.

Growth and Tissue Elemental Composition Response of Spinach (Spinacia oleracea) to Hydroponic and Aquaponic Water Quality Conditions

Abstract: Spinach (Spinacia oleracea cv. Carmel) was grown in a conventional glass greenhouse under three different nutrient solution treatments. Lighting and temperature conditions were identical. Six growing systems were used to provide a duplicate trough system for each of these three treatments. Six trials were harvested from each system over a two month time period. Two treatments received hydroponic nutrient inputs, with one treatment at pH 7.0 (referred to as H7) and the other at pH 5.8 (H5), and the third treatment was aquaponic (A7), receiving all of its nutrients from a single fish tank with koi (Cyprinus carpio) except for chelated iron. System pH was regulated by adding K2CO3 to aquaponic systems and KOH to hydroponic systems. Comparisons made between treatments were total yield, leaf surface area, tissue elemental content, and dry weight to fresh weight ratio. Dry weight biomass yield values were not different in pairwise comparisons between treatments (A7 vs. H5: p = 0.59 fresh weight, p = 0.42 dry weight). Similarly, surface area results were not different between treatments. The important comparison was that A7 achieved the same growth as H5, the conventional pH with a complete inorganic nutrient solution, despite unbalanced and less than “ideal” nutrient concentrations in the A7 condition.

Microbial Effects on the Production of Aquaponically Grown Lettuce

Abstract: In the study of aquaponics, questions have risen concerning the role of microbiota upon plant growth. This experiment compared unaltered aquaponic nutrient solution at pH 7.0 (treatment A7) with sterilized aquaponic nutrient solution at pH 7.0 (treatment SA7) to quantify effects that live microorganisms had on the growth of lettuce (Lactuca sativa). Baseline comparisons were made to conventional hydroponic conditions using inorganic nutrients at pH 5.8 (treatment H5) or pH 7.0 (treatment H7), which showed a 51% reduction in lettuce fresh weight (FW) growth, indicating a strong negative effect of the higher pH nutrient solution; a similar large difference (38%) occurred for dry weight (DW) comparisons between these two treatments. No difference occurred between the sterilized aquaponic treatment (SA7) and H5 in FW or DW. H5 produced more FW and DW than the non-sterile aquaponic treatment (A7). Responses were not different in FW and DW between the two aquaponic conditions. Reduced FW and DW of A7 compared to H5 may be related to the 50 times higher microbial community living in the A7 treatment water than in H5 at the beginning of each trial. Given that the sterile aquaponic solution SA7 and the H5 hydroponic condition were not different in performance, we concluded that the beneficial effects of the microbial community in the fish recirculating aquaculture system (RAS) occurred before the water was sterilized. An interesting implication of our findings is that an RAS can be decoupled from the hydroponic growing system, since its benefits are not dependent upon continuous recirculation between the plant and fish system and its living biotic community.

Growth and Tissue Elemental Composition Response of Butterhead Lettuce (Lactuca sativa, cv. Flandria) to Hydroponic and Aquaponic Conditions

Abstract: The primary objective of this research was to compare lettuce performance under conventional hydroponics at pH 5.8 (referred to as H5), hydroponics at pH 7.0 (referred to as H7), and recirculated aquaponic water at pH 7.0 (referred to as A7). Aquaponic nutrients were supplied by continuously recirculating water between a fish rearing system (recirculating aquaculture system or RAS) and the lettuce growing system (with the sole addition being chelated iron). This paper builds upon our previous research where we found that H7 produced 26% less shoot fresh weight (FW) growth than H5 and an 18% reduction in dry weight (DW). In this research, we also evaluated the inorganic hydroponics nutrient solution at pH 7.0 (H7) to provide continuity between experiments and to isolate the pH effect. The A7 plant biomass responses were not different from H5 in all biomass response categories. H7 was different from H5 in shoot FW, DW, and DW/FW, as well as root FW and DW. H7 was different from the A7 in shoot FW, DW/FW, and root DW. There were no tissue elemental differences between H5 and H7 except Cu. The Ca and Na contents differed between H5 and A7, while the microelements Mn, Mo, and Zn differed. Generally, the elemental tissue differences between treatments were proportional to the differences for the same elements in the nutrient solutions. Aquaponic systems are often viewed to be more complicated and more risky because two complex systems are being joined (hydroponics plus RAS). However, the aquaponics system proved to be surprisingly simple to manage in daily operations. Our data suggested that the aquaponics system (A7), which was operated at a higher pH 7.0, was able to offset any negative biomass and elemental effects that occurred in the inorganic hydroponic pH 7.0 treatment (H7) from its increased pH and less optimized nutrient solution elemental concentrations.

Monitoring of Fluorescence Characteristics of Satsuma Mandarin (Citrus unshiu Marc.) during the Maturation Period

Abstract: Monitoring the maturation process of Satsuma mandarin (Citrus unshiu Marc.) by determining the soluble solids (SS) and acid content non-destructively is needed. Fluorescence components potentially offer such means of accessing fruit maturity characteristics in the orchard. The aim of this study was to determine the potential of fluorescence spectroscopy for monitoring the stage of citrus maturity. Four major fluorescent components in peel and/or flesh were found including chlorophyll-a (excitation (Ex) 410 nm, emission (Em) 675 nm) and chlorophyll-b (Ex 460 nm, Em 650 nm),polymethoxyflavones (PMFs) (Ex 260 nm and 370 nm, Em 540 nm), coumarin (Ex 330 nm, Em 400 nm), and a tryptophan-like compound (Ex 260 nm, Em 330 nm). Our results indicated a significant (R2 = 0.9554) logarithmic ratio between tryptophan-like compoundsExEm and chlorophyll-aExEm with the SS:acid ratio. Also, the log of the ratio of PMFs from the peel (ExExEm was significantly correlated with the SS:acid ratio (R2 = 0.8207). While the latter correlation was not as strong as the former, it does demonstrate the opportunity to develop a non-destructive field measurement of fluorescent peel compounds as an indirect index of fruit maturity.

Horticultural Loss Generated by Wholesalers: A Case Study of the Canning Vale Fruit and Vegetable Markets in Western Australia

Abstract: In today’s economic climate, businesses need to efficiently manage their finite resources to maintain long-term sustainable growth, productivity, and profits. However, food loss produces large unacceptable economic losses, environmental degradation, and impacts on humanity globally. Its cost in Australia is estimated to be around AUS$8 billion each year, but knowledge of its extent within the food value chain from farm to fork is very limited. The present study examines food loss by wholesalers. A survey questionnaire was prepared and distributed; 35 wholesalers and processors replied and their responses to 10 targeted questions on produce volumes, amounts handled, reasons for food loss, and innovations applied or being considered to reduce and utilize food loss were analyzed. Reported food loss was estimated to be 180 kg per week per primary wholesaler and 30 kg per secondary wholesaler, or around 286 tonnes per year. Participants ranked “over supply” and “no market demand” as the main causes for food loss. The study found that improving grading guidelines has the potential to significantly reduce food loss levels and improve profit margins.

Accessible Morphological and Genetic Markers for Identification of Taioba and Taro, Two Forgotten Human Foods

Abstract: Some tropical species—such as the domesticated Xanthosoma sagittifolium (L.) Schott (Taioba) and Colocasia esculenta (L.) Schott (Taro)—have similar phenotypic characteristics, especially in the shape and color of the leaves and petioles which generate uncertainty in their identification for use in human food. This study aimed to analyze the morphological and molecular characteristics of X. sagittifolium and C. esculenta that may help in the popular and scientific identification of these species. The principal morphological characteristics of X. sagittifolium were as follows: leaves with subcoriaceous textures, basal insertion of the petiole, green pseudo-stem in the basal portion with exudate being white and the presence of two collector veins. Distinctive morphological characteristics of C. esculenta were as follows: leaves with velvety textures, peltate insertion of the petiole, pink pseudo-stem in the basal portion with pink exudate and presence of one collector vein. The morphological characteristics that can be used to distinguish Taioba from Taro are the basal petiole insertion of the first, against the petiole insertion near the center of the blade of the latter. Molecular analyses using eight Inter-Simple Sequence Repeat (ISSR) molecular markers simultaneously showed distinctive fingerprints for each of the species. These results contribute to the proper identification of the species used as a food source.

Compatibility of Ten Elite Cocoa (Theobroma cacao L.) Clones

Abstract: One way of boosting cocoa productivity which has plummeted over the last decade in Cote d’Ivoire is to introduce high performing clones. Preliminary observations have indicated that these new clones have differing growth patterns and agronomic traits in the field. Assessing their compatibility is of paramount importance since these clones will be made available to the farmers in the near future. This study was conducted in Soubre, southwest of Cote d’Ivoire, to evaluate the compatibility of ten new cocoa clones (coded as C1, C8, C9, C14, C15, C16, C17, C18, C20, and C21). A half diallel design consisting of 10 self-pollinations and 45 inter-crosses, replicated three times, was used. Results showed significant differences among clones for pollination success. Out of the ten clones evaluated, six (C1, C8, C9, C15, C17 and C21) were self-compatible. With a 39% mean pollination success, C9 was quite interesting because it has been reported to be among the highest yielding clones. Introduction of improved germplasm will go a long way towards enhancing productivity in Cote d’Ivoire, radically impact farmers’ livelihoods, and contribute significantly to a more reliable supply of cocoa beans for chocolate manufacturers.

Optimising Crop Selection for Small Urban Food Gardens in Dry Climates

Abstract: The net value of urban agriculture has not been studied, especially accounting for the cost of water. This study has sought to remedy this gap in the literature by examining the varying price of water in different climates. A two-stage linear programming model has been used to maximise the net value of urban agriculture. The decision variables included the type and yield of crops; constraints included upper and lower bounds of dietary food groups, individual foods, protein and energy as well as area utilised per person. The results show optimal crop regimes are similar across different climates and water prices due to the selection of crops that have high profit margins. The results also showed that per capita garden size is critical with smaller gardens optimal in terms of water applied per unit area and net value returned as well as return per unit area due to the ability to select the highest value crops. Generally, the more high-value and low water-use crops that can be included, the higher the value in larger gardens. The results indicate that a modest food garden growing the right crops can be highly cost-effective, even with conservative crop yields and water use.

Relationship marketing: A qualitative case study of new-media marketing use by Kansas garden centers

Abstract: A primary factor limiting the expansion of many Kansas garden centers is marketing. Most of these businesses spend the majority of advertising dollars on traditional media (newspaper, radio, etc.). However, new-media tools such as social-media can be an effective method for developing profitable relationships with customers. The purpose of this qualitative study was to explore the perceptions and experiences of garden center stakeholders as they use new-media to market their businesses. Grunig’s Excellency Theory served as the theoretical framework for this study. Results indicate garden center operators prefer to use traditional media channels to market to their customers and asynchronously communicate with their target audiences. Stakeholders often have inaccurate or conflicting views of traditional media and new-media in regard to advertising and tend to approach new-media marketing from a public information or asynchronous viewpoint.

Productivity Benefits from Plastic Mulch in Vegetable Production Likely to Limit Adoption of Alternate Practices that Deliver Water Quality Benefits: An On-Farm Case Study

Abstract: Intensive tillage, high fertiliser inputs, and plastic mulch on the soil surface are widely used by vegetable growers. A field investigation was carried out to quantify the impact of alternate land management and fertiliser practices designed to improve offsite water quality on the productivity of vegetable rotations within a sugarcane farming system in a coastal region of subtropical northeast Australia. Successive crops of capsicum and zucchini were grown in summer 2010–2011 and winter 2011, respectively, using four different management practices. These were ‘Conventional’—the current conventional practice using plastic mulch, bare inter-rows, conventional tillage, and commercial fertiliser inputs; ‘Improved’—a modified conventional system using plastic mulch in the cropped area, an inter-row vegetative mulch, zonal tillage, and reduced fertiliser rates; ‘Trash mulch’—using cane trash or forage sorghum residues instead of plastic mulch, with reduced fertiliser rates and minimum or zero tillage; and ‘Vegetative mulch’—using Rhodes grass or forage sorghum residues instead of plastic mulch, with minimum or zero tillage and reduced fertiliser rates. During the second vegetable crop (zucchini), each management practice was split to receive either soil test-based nutrient inputs or a common, luxury rate of nutrient addition. The ’Trash mulch’ and ‘Vegetative mulch’ systems produced up to 43% lower capsicum and zucchini yields than either of the plastic mulch systems. The relative yield difference between trash systems and plastic mulch management systems remained the same for both the soil test-based and high nutrient application strategies, suggesting that factors other than nutrition (e.g., soil temperature) were driving these differences.

Economic Cost-Analysis of the Impact of Container Size on Transplanted Tree Value

Abstract: The benefits and costs of varying container sizes have yet to be fully evaluated to determine which container size affords the most advantageous opportunity for consumers. To determine value of the tree following transplant, clonal replicates of Vitex agnus-castus L. [Chaste Tree], Acer rubrum L. var. drummondii (Hook. & Arn. ex Nutt.) Sarg. [Drummond Red Maple], and Taxodium distichum (L.) Rich. [Baldcypress] were grown under common conditions in each of five container sizes 3.5, 11.7, 23.3, 97.8 or 175.0 L, respectively (#1, 3, 7, 25 or 45). In June 2013, six trees of each container size and species were transplanted to a sandy clay loam field in College Station, Texas. To determine the increase in value over a two-year post-transplant period, height and caliper measurements were taken at the end of nursery production and again at the end of the second growing season in the field, October 2014. Utilizing industry standards, initial costs of materials and labor were then compared with the size of trees after two years. Replacement cost analysis after two growing seasons indicated a greater increase in value for 11.7 and 23.3 L trees compared to losses in value for some 175.0 L trees. In comparison with trees from larger containers, trees from smaller size containers experienced shorter establishment times and increased growth rates, thus creating a quicker return on investment for trees transplanted from the smaller container sizes.