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Under semi-arid soil conditions, soils are poor in nutrient availability due to the high clay and lime content and high pH; hence, mycorrhizal inoculation is a good strategy for sustainable agriculture. As it is still very difficult to produce a large quantity of mycorrhizal inoculum for a large area, it is reasonable to produce mycorrhizal-inoculated seedlings, which are then transplanted to the field. In order to investigate the effect of mycorrhizal inoculation (Glomus mosseae) techniques on plant yield and nutrient uptake of several horticultural plants, field experiments were conducted using a selected Menzilat soil series (Entic Chromoxerert), located in the Research Farm, Faculty of Agriculture, University of Cukurova, (eastern Mediterranean region) Turkey. Two growth pot sizes and two inoculation technique combinations consisting of six horticultural plants were replicated three times in a factorial randomized block design. The pure culture of G. mosseae was maintained and multiplied with sorghum under glasshouse conditions. Pepper, eggplant, tomato, cucumber, melon and watermelon seedlings were produced in different growth media, comprised of different composting material with several mycorrhizal species. Seedlings were produced using different techniques. Mycorrhizal-inoculated and non-inoculated seedlings were grown under field conditions using different inoculation techniques. The experiments revealed that under field conditions, mycorrhiza-inoculated seedlings are effectively established and result in high plant growth and yield. The results also revealed that for both techniques, plant yields were higher and mycorrhizal-inoculated plants produced more yield than non-mycorrhizal plants. The results showed that mycorrhizal-inoculated plants had higher P and Zn content than non-inoculated plants, but immersed mycorrhizal-inoculated plants had higher P concentration compared with granular application. We conclude that seedling quality is dependent on growth medium and mycorrhizal spore effectiveness. Furthermore, using mycorrhizal-inoculated seedlings appears to be a good strategy for horticultural production. © 2019 International Society for Horticultural Science. All rights reserved.

Supplemental lighting is essential for year-round greenhouse crop production in regions with low natural light. Supplemental lighting to increase the daily light integral can be added via lengthening photoperiods or increasing light intensity. Light addition via long photoperiods is preferred because of the lower light-fixture costs in comparison with the use of high light intensity. However, long photoperiods cause photoinjury, such as leaf chlorosis in tomatoes and sweet peppers. This photoinjury has limited the yield increase from long-photoperiod lighting. In our previous study, we found that a temperature drop with dynamic temperature integration (TI) can promote photoassimilate translocation from leaf to fruit and thus has the potential to reduce photoinjury. Therefore, this study was initiated in 2013 with the aim of testing this temperature-control strategy to improve the response to long photoperiods, including both overhead high-pressure sodium (HPS) lighting and light-emitting diode (LED) intra-canopy lighting. The study was conducted over three winters (from 2013 to 2016) in eight greenhouse compartments, each with 50 m2 growing area. Two photoperiods (control and long photoperiod) of overhead HPS lighting and two temperature integration strategies (control TI with no temperature drop; dynamic TI with a temperature drop to 13.5°C for tomatoes or 15.5°C for sweet peppers at the end of the photoperiod) were applied in eight greenhouse compartments. Four intra-canopy LED photoperiods were applied to the four plots inside each compartment. Dynamic TI with a temperature drop significantly reduced photoinjury and increased fruit yield at long photoperiods for both tomatoes and sweet peppers. It also reduced heating energy use during cold winter months in the tomato experiments. Therefore, dynamic TI with a temperature drop is an energy-efficient climate-control strategy for improving the response of greenhouse tomatoes and sweet peppers to long photoperiods of supplemental lighting.