Legume-Based Mobile Green Manure Can Increase Soil Nitrogen Availability and Yield of Organic Greenhouse Tomatoes

Information about the availability of soil mineral nitrogen (N) in organic greenhouse tomatoes after the application of mobile green manure (MGM), and its impact on plant nutrient status and yield is scarce. Considering this knowledge gap, the effects of legume biomass from faba beans that are cultivated outdoors (FAB), or from feed-grade alfalfa pellets at two different doses (AAL = 330 g m−2; AAH = 660 g m−2) that were applied as MGM on the nutrition and yield of an organic greenhouse crop of tomatoes were evaluated. All of the MGM treatments increased the mineral N concentrations in the soil throughout the cropping period, and the total N concentration in tomato leaves when compared to the untreated control. FAB and AAH treatments had a stronger impact than AAL in all of the measured parameters. In addition, AAL, AAH, and FAB treatments increased the yield compared to the control by 19%, 33%, and 36%, respectively. The application of MGM, either as faba bean fresh biomass or as alfalfa dry pellets, in organic greenhouse tomatoes significantly increased the plant available soil N, improved N nutrition, and enhanced the fruit yield. However, the N mineralization rates after the MGM application were excessive during the initial cropping stages, followed by a marked decrease thereafter. This may impose an N deficiency during the late cropping period.

Light Spectra and Root Stocks Affect Response of Greenhouse Tomatoes to Long Photoperiod of Supplemental Lighting

Plant biomass and yield are largely dictated by the total amount of light intercepted by the plant (daily light integral (DLI)—intensity × photoperiod). It is more economical to supply the desired DLI with a long photoperiod of low-intensity light because it uses fewer light fixtures, reducing capital costs. Furthermore, heat released by the light fixtures under a long photoperiod extended well into the night helps to meet the heating requirement during the night. However, extending the photoperiod beyond a critical length (>17 h) may be detrimental to production and lead to leaf chlorosis and a reduction in leaf growth and plant vigor in greenhouse tomato production. It is known that red light can increase leaf growth and plant vigor, as can certain rootstocks, which could compensate for the loss in plant vigor and leaf growth from long photoperiods. Therefore, this study investigated the response of tomatoes grafted onto different rootstocks to a long photoperiod of lighting under red and other light spectra. Tomato plants ‘Trovanzo’ grafted onto ‘Emperator’ or ‘Kaiser’ were subjected to two spectral compositions—100% red or a mix of red (75%), blue (20%), and green (5%) light for 17 h or 23 h. The four treatments supplied similar DLI. Leaf chlorosis appeared in all plants under 23 h lighting regardless of spectral compositions between 20 and 54 days into the treatment. The yield for 23 h mixed lighting treatment was lower than both 17 h lighting treatments. However, the 23 h red lighting treatment resulted in less leaf chlorosis and the plants grafted onto ‘Emperator’ produced a similar yield as both 17 h lighting treatments. Therefore, both spectral compositions and rootstocks affected the response of greenhouse tomatoes to long photoperiods of lighting. With red light and proper rootstock, the negative yield impact from long photoperiod lighting can be eliminated.

The influence of irrigation methods on the water regime and productivity of greenhouse tomatoes

Relevance. The water regime is one of the main processes in the life of the plant, optimizing which can increase the yield of cultivated crops. In protected ground conditions, the plants' water needs are met exclusively by irrigation. Irrigation is the most important means of increasing the yield of greenhouse crops, including tomato. Greenhouse tomatoes are very demanding on soil moisture, as well as on air humidity. To combat overheating of the air and plants, and to increase the relative humidity of the air in greenhouses, plants for evaporative cooling and humidification of plants are successfully used, which are especially effective in drip irrigation. The combination of drip irrigation with evaporative cooling makes it possible to control the water regime of the soil and air habitat of plants.Materials and Methods. The purpose of the research: to identify the most optimal method of water supply for greenhouse tomatoes. The research was conducted in 2018-2019 in the greenhouse complex "Yugagroholding", located in the suburbs of the city of Makhachkala. The object of research was a hybrid of tomato Mei shuai. The experiments included three options: sprinkling, drip irrigation, and drip irrigation with evaporative cooling.Results. The comparative characteristics of irrigation methods by yield are presented, the results of which indicate the advantage of the second and third options over sprinkling: the highest yield was obtained in the third option and amounted to 14.7 kg/m2 . The best methods of water supply that ensure the optimal water regime of greenhouse tomatoes are identified-drip irrigation and drip irrigation in combination with evaporative cooling, the latter is the best in most indicators.

Meloidogyne ethiopica (Root-knot nematode).

M. ethiopica is a polyphagous pest and classed as a tropical and temperate root-knot nematode (RKN) species (Strajnar et al., 2011). M. ethiopica is considered a damaging species as it can multiply on many different types of plants (including both dicotyledons and monocotyledons). Originally considered a tropical species, it has been shown to survive outdoors in temperate areas also. The distribution in Africa is unknown. Only in Chile is it considered an invasive nematode. In Chile it occurs over a range of ca 1000 km and has been detected from the Copiapó valley, ca 800 km north of Santiago, to Talca, ca 250 km south of Santiago and it is found on grapevine (Vitis vinifera), kiwi (Actinida deliciosa C.) and potatoes in 80% of samples (Carneiro et al., 2007) collected in this area. It was introduced in Brazil from Chile on kiwi seedlings, and despite not being invasive in Brazil it has caused serious economic problems to grapevine in Chile (Carneiro et al., 2007). Recently, this species has also been recorded on asparagus (Asparagus officinalis L.) in Peru (Murga-Gutierrezet al., 2012). In Europe it has been detected only in Slovenia, on greenhouse tomatoes (Solanum lycopersicum L.) (Širca et al., 2004). It was added to the EPPO Alert List in 2011.

Effects of LED and HPS lighting on the growth, seedling morphology and yield of greenhouse tomatoes and cucumbers

In an experiment with tomato and cucumber transplants, light units equipped with purpose-built LED arrays were compared with HPS sodium lamps with a power of 600 W and a voltage of 230 V. For both the LED and HPS lamps, the same PAR radiation level was used at the plant height, which was about 70–80 μmol/m2/s in conditions without daylight. The supplementary lighting was carried out for 8 to 24 hours and was switched on during the day when the solar radiation outside the greenhouse was lower than 200 W/m2. The supplementary lighting with the LED and HPS lamps did not have a significant impact on the growth of the tomato and cucumber seedlings and the fresh and dry mass of the tomato and cucumber plants. The plants grown without the additional artificial lighting were significantly smaller in height, had fewer leaves, a smaller spread and produced lower fresh and dry weights. The tomato and cucumber plants grown under the LED lamps had a higher chlorophyll index than those grown under the HPS lamps and without any lighting. The supplementary lighting with the LED lamps increased the early yield of the tomatoes compared to the HPS and control plants but has no effect on the early yield of the cucumbers. Both the LED and HPS lighting significantly increased the total and marketable yield of the tomatoes and cucumbers.

Soil Surface-Trapping of Tomato Leaf-Miner Flies Emerging from Underground Pupae with a Simple Electrostatic Cover of Seedbeds in a Greenhouse

In the present study, an electrostatic apparatus for trapping adult tomato leaf miner flies (Liriomyza sativae) emerging from underground pupae at the surface of a seedbed in an organic greenhouse was developed. The apparatus consisted of insulated iron rods arranged in parallel at set intervals and linked to a voltage generator, which supplied a negative charge to the rods, as well as non-insulated grounded iron rods with the same configuration. The two layers of insulated and non-insulated iron rods were arrayed in parallel to form a static electric field between the layers. The electric field created a strong attractive force capable of capturing flies that entered the field. In a greenhouse assay, the apparatus was placed horizontally above a seedbed in a greenhouse and surveyed for its ability to capture adult flies emerging from pupae that were introduced onto the seedbed beneath the apparatus. The results revealed that the apparatus effectively trapped all adult flies that emerged from the pupae and that it functioned stably while continuously operated during the entire period of the experiment. Thus, our novel apparatus is a promising tool for the physical control of adult tomato leaf miners in the insecticide-independent cultivation of greenhouse tomatoes.

Residue Content of Organophosphorus Pesticides and their Toxic Metabolites in Greenhouse-Grown Tomatoes during Pre-Harvest Interval and Post-Harvest Processing: A Kinetic Study

Background: Organophosphorus pesticides (OPPs) have a wide application throughout the world and exert adverse effects on human health. Moreover, these chemical compounds are responsible for thousands of deaths per year worldwide. Kinetic and mathematical models could be used to optimize the application of pesticides on fruits and vegetables and monitor their residues. Objectives: The present study aimed to model the dissipation of diazinon and chlorpyrifos in different conditions, such as household conditions (e.g., storage at room and refrigerator temperatures, as well as cooking) and field condition for greenhouse tomatoes. Methods: A multi-residue analysis of diazinon, chlorpyrifos, and their oxon derivatives was established by gas chromatography-tandem mass spectrometry. The limit of quantification (LOQ), recovery, precision, linearity, and the limit of detection (LOD) were evaluated to ensure that the method was able to effectively determine the studied pesticides in the tomato samples. The linear and nonlinear kinetic models were presented for chlorpyrifos and diazinon residues in tomato using zero-order, first-order, and second-order equations. Results: Based on the best fitting models for diazinon in the case of laboratory treatment at the refrigerator, room, and boiling temperatures, the half-lives were calculated as 18.79 days, 11.41 days, and 45.39 min, respectively. The half-life of diazinon was lower than that of chlorpyrifos in both field and laboratory treatments. Conclusion: Modeling the removal of the pesticides indicated that the nonlinear first- and second-order models were the best fitted models for the dissipation of both pesticides in field and post-harvest conditions.