Quality and Yield of Lettuce in an Open-Air Rooftop Hydroponic System

In this study, the yield and growth performance of lettuce in an open-air rooftop hydroponic system were investigated. Lettuce was grown in a closed recirculating nutrient film technique (NFT) unit using a standard nutrient solution (NS). Yield, fresh weight, and nutrient content in the leaf tissue of the harvested lettuce were measured. The results were compared with the results obtained in indoor hydroponic lettuce growth with artificial lightning. Despite strong winds during the growth period, 25% of the total lettuce heads weighed twice the marketable weight; however, 25% of the total lettuce heads were below the marketable weight. A more efficient nutrient uptake was indicated by the lettuces in the rooftop system compared with the uptake in the indoor system. Foliar analysis revealed a higher content of all nutrients in the leaves of rooftop hydroponic lettuce compared with indoor hydroponic lettuce. This study suggests that hydroponic rooftop-grown lettuce can be competitive with their indoor counterparts if the rooftop hydroponic system is protected from extreme weather conditions.

Diagnose apricot nutritional status according to foliar analysis

This experiment was conducted in Cacak (Western Serbia) during 2004 and 2005 to determine the influence of Belosljiva, Dragacevka, Stanley, Kolenstockzwetsche, Wangenheim, Pozegaca, and Kapavac interstocks budded on Myrobalan seedlings on the seasonal changes, leaf macronutrient contents at 120 days after full bloom (DAFB) and deviation from optimum percentage (DOP) of Vera apricot cultivars. The macronutrients analyzed were N, P, K, Ca, and Mg. Nitrogen was consistently decreased during the vegetative cycle on all interstocks, while leaf P, Ca, and Mg had a tendency of increasing, except P on Kapavac. Potassium had a tendency to increase from 60 to 150 AFB, and decreased through 180 DAFB. Leaf N at 120 DAFB was higher in 2005, and P, K, Ca, and Mg in 2004 on all interstocks. Leaf macronutrients were significantly influenced by interstocks, except K. On the basis of DOP index, leaf N, Ca, and Mg were lower than optimum on all interstocks in both years. Leaf P and K were higher than optimum. Stanley and Wangenheim showed the weakest balanced nutritional values than the rest of interstocks.  

Comparative Foliar Epidermal Studies in Coix lacryma-jobi L. andCoix aquatica Roxb. (Poaceae)

As micromorphological knowledge was not available for Coix aquatica Roxb., the foliar epidermal studies were carried out for Coix lacryma-jobi L. and Coix aquatica Roxb. with the aim of determining the patterns of variation in their epidermal characteristics and assessing their value in species identification. Comparative foliar analysis was carried out by using light microscopy, after following routine scraping method. The characters of diagnostic importance in the identification of C. aquatica are the sparsely distributed prickle hairs with long pointed apex in the abaxial epidermis and dumbbell shaped silica cells in both the epidermises. The diagnostic characters for C. lacryma-jobi are the cross shaped silica cells and dumbbell shaped on the abaxial and adaxial epidermis respectively. The observed differences in certain micromorphological characters helps in identification of presently studied two species of Coix.

Growth of Barberry Liners in Media Amended with Noncomposted Recycled Waste

One-year-old `Royal Burgundy' barberry (Berberis thunbergii var. atropurpurea) liners were potted in 1-gal (3.8-L) containers. Container media consisted of noncomposted recycled waste mixed at rates of 0% (control), 25%, 50%, 75%, and 100% by volume with a (by volume) 3 pine bark: 2 peat: 1 sand media. Treatments were replicated eight times. Three grams (0.1 oz) of Osmocote 13-10-13 (13N-4.37P-10.8K) with micronutrients were topdressed on all containers. Media electrical conductivity (EC) and pH readings were recorded every fifteen days over the course of 5 months. Dry shoot, root, and total weights were recorded at the end of the project and a foliar analysis was performed for nutrient and metal content. Results indicate a general trend of higher EC with greater volumes of recycled waste. EC levels for the control and 25% treatment were within recommendations for the optimal plant growth of plants for the duration of the study. All treatments had an acceptable pH level for plant growth. Nitrogen levels were below the recommended foliar analysis sufficiency range. Levels of phosphorus and potassium were above or within the recommended foliar analysis sufficiency range. Metals were below or within recommended ranges for all treatments. Total dry weights revealed no statistical difference between the control, 25%, 50%, and 75% treatments. This study indicates that 25% noncomposted recycled waste could be used in container media for production of `Royal Burgundy' barberry.