Winter-spring Cycle Research Articles

Parametric Analysis of a Radiant Gas Heating System for Controlled-Environment Agriculture with Preheated Ventilation

This article explores the fundamental principles of the software method for calculating the gas-fired heating system of a cultivation structure, where the main source of heat is provided by ceiling-mounted gas infrared radiators. To maintain the required thermal regime within the premises, a gas air heater is utilized, designed to preheat the outdoor air to the necessary temperature before supplying it to the heated space.The calculation method is based on solving a system of interconnected equations of thermal and material balances for the cultivation structure, its enclosure, and the soil surface. Possible utilization of thermal energy from high-potential combustion products of gaseous fuel is taken into account.Using the example of the “Farmer 7.5” industrial greenhouse (Russian Federation), designed for year-round cultivation of plants in closed soil (in this case, cucumbers were the subject of study until the fruitbearing stage in the winter-spring cycle), the impacts of various factors are investigated: outside air temperature, thermal resistance of the enclosing structure on the heating system’s thermal power (in combination with the gas air heater), and variable parameters of the microclimate. The latter includes the enclosure temperature of the industrial greenhouse and the intake air temperature for general exchange ventilation needs. Specific conclusions and prospects for further scientific research are drawn based on the obtained results.

Photosynthesis, Yield and Quality in Wild Rocket (Diplotaxis tenuifolia L.) under Photoluminescent Greenhouse Covers

Manipulation of light spectral composition is a useful tool to drive morphological, physiological and metabolic responses in several crops, ultimately improving yield and quality. Novel materials for greenhouse covering are being developed in order to make a better use of the available sunlight: among these are the cover films or panels incorporating fluorescent additives which are able to convert UV solar radiation into visible light. In this research, we compared the physiological traits and the agronomical performance of wild rocket grown in pots in the winter–spring season, under four different greenhouse prototypes covered with poly-methyl-methacrylate (PMMA)-based panels. PMMA panels doped at 3% (Dop3) or 7% (Dop7) w/w with a blend of rare-earth elements (partially converting the solar UV radiation to red and blue wavelengths) were compared with an undoped (UD) and a whitewashed (WW) PMMA greenhouse. The rocket yield was higher in Dop3 (+30%), while it was unaffected in Dop7 and lower in WW (−39%), compared to the control (6.06 kg m−2). The leaf greenness decreased while both the ABTS and the hydrophilic antioxidant activities increased under the doped and the whitewashed greenhouses. The Dop3 treatment provided the best results in terms of yield and quality of greenhouse wild rocket in winter–spring cycle. However, the analysis of OJIP kinetics of chlorophyll fluorescence revealed that the main factor affecting the photosynthetic performance was the light intensity inside each greenhouse rather than the modulation of light spectrum, because of the different shading properties of the doping and whitewashing treatments. Although these results did not allow us to distinguish between the combined effects of shading and light spectrum modulation, the use of photoluminescent covers can be foreseen as a promising innovation in greenhouse horticulture.

Freeze and thaw field investigation of foamed asphalt cold recycling mixture in cold region

Cold recycling mixtures with foamed asphalt is one of the green and environmental-friendly construction technology in pavement rehabilitation. Most of the pavement recycling materials could be utilized with this kind of technology. Water, cement, aggregate and foamed asphalt will be added into the recycling asphalt pavement materials at the room temperature during the production of cold recycling mixtures. However, adding water into the mixtures may have a negative effect on the adhesion among foamed asphalt, new aggregate and recycling asphalt pavement materials. Especially in cold regions, the existence of excessive water in the mixtures may introduce the freeze-thaw durability issues during the winter-spring cycle. Therefore, it is important to clarify this durability issue of the foamed asphalt cold recycling mixtures in cold regions. In this study, an expressway pavement rehabilitation project with foamed asphalt cold recycling mixtures in the north of China had been selected to be test road. After initial material design in lab, the foamed asphalt cold recycling mixtures had been paved as the base layer. Then the field coring had been conducted, at the end of curing time and also after a freeze-thaw cycle. The performance tests on these coring samples indicate that the effect of freeze-thaw on the durability of the foamed asphalt cold recycling mixtures can not be neglected. The indirect tensile strength at dry and wet conditions, the modulus, and the fracture properties of the foamed asphalt cold recycling mixtures all had an obvious deterioration after undergoing the winter-spring cycle. Therefore, more structural frozen-resistant protection behaviors and advanced material design should be researched in the future.

«Lighting price» of cucumber yield in the winter-spring turnover of greenhouses

Relevance. Among the main factors that determine the productivity of vegetable yields in protected ground, the main one is light. For the formation of 1 kg/m2 of cucumber fruits with a length of 18-22 cm, on average about 3500-4000 J/cm2 of solar radiation is required. In the winter-spring cycle, in the absence of artificial lighting in greenhouses, there is an unevenness of scattered solar radiation and a general shortage of incoming light energy. At the same time, the amount of total solar radiation required for the formation of a 1 kg of fruit ("lighting price") is not the same for different hybrids. To increase the profitability of production in the winter-spring turnover in greenhouses that are not equipped with artificial lighting, it is necessary to choose hybrids with the lowest "lighting price" of the crop, that is, hybrids that use less light energy to form a 1 kg of fruit.The purpose of the study: evaluation of F1 hybrids of cucumber on the basis of resistance to lack of lighting by comparing their "lighting price" of the crop: how much energy is spent on the formation of 1 kg of marketable products.Methods. The research was carried out at the variety testing site in the Crimean breeding Center of the Scientific Research Institute of Vegetable Crop Selection "Gavrish", in the conditions of winter-spring turnover, in greenhouses not equipped with artificial lighting. We tested seven medium-fruited (18-22 cm) spined-fruited cucumber hybrids recommended for growing in winter-spring turnover.Results. The analysis of the data on the input of solar radiation and the formation of a standard yield showed that there is a direct relationship between the amount of incoming light and the level of productivity. The period of conversion of the received solar energy into the fruit harvest varied during the growing season from 14 to 8 days, depending on the degree of plant development. The "lighting price" of the crop was not the same for different hybrids: the hybrids tested in the experiment spent an average of 2900 J/cm2 per 1 kg of product, which is 18% more efficient than for standard greenhouse cucumbers.

Production and quality of zinnia under different growing seasons and irrigation levels

ABSTRACT Zinnia (Zinnia elegans Jacq.) is a fast-growing and easy to cultivate plant that has flowers of different colors. This species has become an option to be introduced commercially in many countries as cut flower and its floral quality is influenced by different cultivation techniques. We evaluated the production and the quality of floral stems of zinnia (cv. Red California Giant) in response to growing seasons and irrigation levels. In a greenhouse located in Rio de Janeiro (Brazil), zinnia plants were grown in two cycles (autumn-winter and winter-spring) in pots with water replacement corresponding to 46, 64, 75 and 100% of their water requirement. Based on the stem length and diameter and on the flower diameter, there was variation in the quality of the stems produced in the growing seasons evaluated. All stems from the autumn-winter cycle were classified as A1 (high quality), while almost 9% of the stems from the winter-spring cycle were classified as A2 (medium quality). There was a linear growth trend in the production and quality of zinnia stems with the increase of the irrigation level in most cases, as well as significant effect of the growing seasons, with the best results of number of stems, fresh weight, length and diameter of the stem and flower diameter found in the autumn-winter cycle. The weather conditions of this cycle favor the production and quality of zinnia floral stems, and the replacement of 100% of the specie’s water requirement is recommended in both cultivation cycles.

Grain and Flour Wheat Quality Modified by Genotype, Availability of Nitrogen, and Growing Season

The objective of the present study was to determine physical and chemical parameters that determine grain and flour quality of wheat grown in Mexico’s highlands (Toluca, Estado de Mexico) as a response of nitrogen fertilization and growing season. Experiments were carried out in winter-spring 2010 (irrigation) and summer-autumn 2011 (rainfed) season cycles. Nine wheat cultivars were tested under four levels of nitrogen fertilization (N00, N100, N200, and N300 kg N·ha−1) with a population density of 336 seeds m−2. For each growing season and N rate, three replications were performed for each experiment under a randomized complete block design. Best quality indexes were obtained in the winter-spring cycle as a result of genetic variability. Nitrogen availability modified significantly some quality parameters (grain and flour protein, test weight, and hardness) obtaining the highest values at a rate of 100 kg N·ha−1. On the other hand, volume of sedimentation showed positive effects only at a rate of 300 kg N·ha−1. This rate showed positive effects on grain and flour protein, sedimentation volume, and hardness during the summer-autumn cycle. Eneida F94, Tollocan F2005, and Urbina S2007 cultivars presented the highest grain and flour protein content of tested varieties. Finally, Eneida F94 and Tollocan F2005 presented the highest test weight and flour percentage.

Phytosociological research on temporary ponds in Apulia (southern Italy)

The ephemeral hygrophilous vegetation occurring in the temporary ponds of Apulia (southern Italy) weres studied following the phytosociological approach. On the base of 153 phytosociological relevés carried out during the period 2015-2018, 19 associations were identified, of which 16 described for the first time. All the associations belong to the Isoeto-Nanojuncetea class. The surveyed associations can be arranged in two orders, such as Isoetetalia, including those with a winter-spring cycle and Nanocyperetalia, regarding those with a summertime cycle. The identified association has been examined in detail, and for each one, we provided a phytosociological table. The communities belonging to the Isoetetalia are 17 and arranged in four alliances (Isoetion, Preslion cervinae, Cicendio filiformis-Solenopsion laurentiae, Agrostion salmanticae); instead, those ones of Nanocyperetalia are two both included in the Verbenion supinae. In order to highlight the relationships among the associations, all the relevés used for this investigation are processed. Overall, this analysis confirms the autonomy of the associations, grouping them according to the syntaxonomic arrangement proposed by the authors. Taxonomic investigations on the flora occurring in these habitats allowed the detection of two new subspecies of Solenopsis laurentia, both with a different autoecology.

Nutritional, Biophysical and Physiological Characteristics of Wild Rocket Genotypes As Affected by Soilless Cultivation System, Salinity Level of Nutrient Solution and Growing Period.

With the aim of defining the best management of nutrient solution (NS) in a soilless system for obtaining high quality baby-leaf rocket, the present study focuses on two wild rocket genotypes (“Nature” and “Naturelle”), grown in a greenhouse under two Southern Italy growing conditions—autumn-winter (AW) and winter-spring (WS)—using two soilless cultivation systems (SCS)—at two electrical conductivity values (EC) of NS. The SCSs used were the Floating System (FS) and Ebb and Flow System (EFS) and the EC values were 2.5 and 3.5 dS m−1 (EC2.5; EC3.5) for the AW cycle and 3.5 and 4.5 dS m−1 (EC3.5; EC4.5) for the WS cycle. The yield, bio-physical, physiological and nutritional characteristics were evaluated. Higher fresh (FY) (2.25 vs. 1.50 kg m−2) and dry (DY) (230.6 vs. 106.1 g m−2) weight yield, leaf firmness (dry matter, 104.3 vs. 83.2 g kg−1 FW; specific leaf area, 34.8 vs. 24.2 g cm−2) and antioxidant compounds (vitamin C, 239.0 vs. 152.7 mg kg−1 FW; total phenols, 997 vs. 450 mg GAE mg kg−1 FW; total glucosinulates-GLSs, 1,078.8 vs. 405.7 mg kg−1 DW; total antioxidant capacity-TAC, 11,534 vs. 8,637 μmol eq trolox kg−1 FW) and lower nitrates (1,470 vs. 3,460 mg kg−1 FW) were obtained under WS conditions. The seasonal differences were evident on the GLS profile: some aliphatic GLSs (gluconapoleiferin, glucobrassicanapin) and indolic 4-OH-glucobrassicin were only expressed in WS conditions, while indolic glucobrassicin was only detected in the AW period. Compared with EFS, FS improved leaf firmness, visual quality, antioxidant content (TAC, +11.6%) and reduced nitrate leaf accumulation (−37%). “Naturelle” performed better than “Nature” in terms of yield, visual quality and nutritional profile, with differences more evident under less favorable climatic conditions and when the cultivars were grown in FS. Compared to EC2.5, the EC3.5 treatment did not affect DY while enhancing firmness, visual quality, and antioxidant compounds (TAC, +8%), and reducing the nitrate content (−47%). The EC4.5 treatment reduced FY and DY and the antioxidant content. Despite seasonal climatic condition variability, FS and the moderate salinity level of NS (3.5 dS m−1) can be suggested as optimum.

The mineral profile in organically and conventionally grown “early” crop potato tubers

In several regions in the Mediterranean Basin potatoes are grown during the winter-spring cycle, which involves an intensive application of farming inputs. Consequently, the possible health risks and the environmental impact of conventional cropping have fuelled a major expansion of the organic farming sector. The “early” crop potato can be profitably grown organically, but few data have been published to date regarding the product quality. This study was focused on the evaluation of the mineral profile of three “early” potato cultivars (Arinda, Ditta, Nicola) both organically and conventionally produced over two consecutive seasons. The organically grown tubers contained more phosphorus (2.8 vs. 2.3gkg−1 of dry matter) and a comparable quantity of both magnesium and copper (on average 250 and 2.6mgkg−1 of dry matter, respectively) than the conventionally grown ones. However, potassium, calcium, iron, sodium and manganese were all less well represented in organically grown tubers. More phosphorus, magnesium and iron was accumulated by cv. Arinda under organic cultivation, while conventionally grown tubers of cvs. Ditta and Nicola contained more magnesium (270mgkg−1 of dry matter, on average). Organic cultivation can therefore generate tubers with a distinct spectrum of minerals compared to that of conventionally grown tubers. However, both cultivar choice and weather conditions are also important determinants of the mineral profile of the “early” crop potato tuber.

(190) Productive Behavior of Varieties with Different Planting Densities in Okra [Hibiscus esculentus (L.)] Cultivation with Controlled Irrigation

Vegetables are important in Mexican agriculture because of the exportation opportunities made available by the opening of the Free Trade Agreement. Okra represents a potentially profitable crop, and it is important to understand its behavior in a predetermined environment, and determine its optimal sowing density. The present work was realized to evaluate three genotypes and three densities of okra plants in the production and quality of fresh fruit. The work was realized in the winter–spring cycle in the dry tropic region, using a randomized block design with a bifactorial of nine treatments. During the cultivation cycle, the vegetative and productive variables did not present changes in phenology, and only registered differences in plant height (58.4 and 57.6 cm., respectively) of PX 416543 and `Green Best', with a distance between plants of 18 cm. These results indicate that with increased densities of 41,600, 50,000, and 69,444 plants/ha, there were no differences in the number and weight of fresh fruit/plant. Nevertheless, with the production and support the quality of fresh fruit increased. We conclude that high densities of plants increase the total crop of fresh fruit per hectare without affecting quality. The variety PX 416543 presented the best vegetative and productive behavior.

Influence of nitrogen form on yield and nitrate content of subirrigated early potato

AbstractPotato is classified among the vegetables with low nitrate content but, in diet, it contributes most to the daily intake of nitrate, because of its high per capita consumption. Two trials were carried out in winter–spring and autumn–winter cycles using a trough bench subirrigation system. Potato seedlings were transplanted into pots containing peat, pumice and vermiculite in a 3:1:1 volume ratio. Both trials were carried out to compare three nutrient solutions having the same nitrogen concentration (6.4 mM), but different ammonium:nitrate (NH4‐N:NO3‐N) percentage ratios (100:0, 50:50 and 0:100). In the winter–spring cycle, tubers were lower in weight and were more numerous than in the autumn–winter cycle. The tuber yield of ammonium‐fed plants was lower than with the mixed form and 100% NO3‐N, but only in the trial carried out in the winter–spring period. Nitrate‐fed plants yielded a number of tubers almost 3‐fold higher than ammonium‐fed plants. The NO3 content of tubers harvested in spring in the presence of 100% NH4‐N in the nutrient solution was a 25% of that in nitrate‐fed plants (44 vs 169 mg kg−1 of fresh mass); in tubers harvested in winter, with worse light conditions, nitrate content increased with increasing NO3‐N in the nutrient solution (26, 109, and 225 mg kg−1 of fresh mass with NH4‐N:NO3‐N 100:0, 50:50 and 0:100, respectively). The substrate electrical conductivity increased with increasing ammonium concentration in the nutrient solution, and was higher in the upper layer of the substrate. Copyright © 2004 Society of Chemical Industry