Download or read book The Effect of Various Rates of Semicontinuous Drip Irrigation on Lettuce lactuca Sativa L Grown in Greenhouse written by D. Shimshi and published by . This book was released on 1973 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1975-03 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1973 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1975 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Irrigation Efficiency written by Water Resources Scientific Information Center and published by . This book was released on 1973 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Irrigation Efficiency written by Water Resources Scientific Information Center and published by . This book was released on 1973 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accessions of Unlimited Distribution Reports written by and published by . This book was released on 1973-09-14 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Index written by and published by . This book was released on 1975 with total page 1096 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1974 with total page 1088 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Different Rootzone Temperatures and Growth Irradiances on Photosynthesis and Productivity of Three Lettuce Cultivars Lactuca Sativa L Grown Under Tropical Aerial Conditions written by Jie He and published by . This book was released on 1996 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of different irradiances and different rootzone temperature on the growth response of three cultivars of Lactuca sativa L. (a temperate plant) namely Armada, Olympia, and Plama were studied using aeroponic systems under warm aerial temperatures.The rootzone temperatures were modified to 15 C, 20 C and 25 C respectively. The control comprised rootzone that was subjected to diurnal temperatures which ranged from 28 C to 39 C. Plants exposed to different rootzone temperatures were grown under three different light regimes in a greenhouse : 100%, 70% and 40% of prevailing solar radiation with maximal middy irradiances of ca 1800, 1300 and 700 umol m-2s-1 respectively on sunny days. For all the cultivars grown under different rootzone temperatures, photosynthesis rates decreased as the irradiances were decreased.

Download or read book Lettuce Growing in Greenhouses written by Ross Calvin Thompson and published by . This book was released on 1949 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Macronutrient Uptake in Lettuce Lactuca Sativa L written by Francisco Javier Albornoz Gutierrez and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The absorption of N, P, K, Ca, Mg and S was studied in lettuce (Lactuca sativa L. cv. `Black Seeded Simpson') to generate information for the development of a mathematical model to predict the uptake of these nutrients under greenhouse conditions.The diurnal uptake patterns were studied in growth chamber experiments under three air temperatures (10, 25 and 35°C) at two light levels (600 or 1200 [mu]mol m-2 s-1). The rates were analyzed at various plant ages in a greenhouse experiment. The analysis of the hourly uptake rates showed no marked differences between the hours of the day, mainly due to the high variability in the uptake rates among replicates. No differences were found in the absorption between daytime versus nighttime. However, increasing air temperature and light level drove higher total daily uptake rates. The uptake rates of N, P and K declined with plant age following a reduction in plant growth rate.When the uptake of each individual ion was compared to the whole-plant CO2 assimilation rate a significant curvilinear relation was found. The relationships of nutrient uptake with relative growth rate were different for each nutrient, where NO3-, H2PO4- and K+ showed a linear relation, whereas NH4+, Ca2+, Mg2+ and SO42- uptake was related in a curvilinear fashion with RGR.The response of plant growth and leaf photosynthesis to various concentrations of nutrients in the rootzone was also studied in aeroponic culture, under the hypothesis that high oxygen available to the roots would increase plant tolerance to high electrical conductivity (EC) levels. A significant interaction between leaf temperature and rootzone EC was found, where at temperatures below 20°C the rootzone nutrient concentration (and leaf tissue nutrient concentration) had no effect on single leaf photosynthetic rates but when the temperature is increased up to 40°, higher concentrations of nutrients stimulated higher photosynthetic rates. Plants grown in aeroponic culture with high concentration of nutrients (equivalent EC of 12.0 dS m-1) showed a ~30% reduction in plant growth compared to the best treatment (half strength Hoagland's solution, EC: 1.2 dS m-1) and no differences were found in leaf NO3- content. To study the response of plants to uneven supply of nutrients during a day cycle an experiment was conducted in aeroponics where two treatments differing in the nighttime solution concentration versus that applied during the daytime were compared to a third treatment with constant supply of nutrients. It was found that a high difference in the concentration between day and night reduced plant nutrient accumulation and root growth but not total plant growth. The concentration of leaf NO3- was reduced by ~75% when the supply of nutrients was higher during the night than during the day.The information collected in these experiments was compiled into a mathematical model that calculates nutrient demand from photosynthetic and plant growth rates. The model was able to accurately predict the demand for N, P and K in greenhouse conditions, as well as N in field conditions.

Download or read book Lettuce and Its Production written by Thomas Wallace Whitaker and published by . This book was released on 1962 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Growth and Development of Lettuce Lactuca Sativa L in a Hydroponic System with Different Lighting Sources written by and published by . This book was released on 2018 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this study was to investigate the influences of different light systems, on growth parameters (fresh and dry weight, height and width, number of leaves and leaf area) and accumulation of chlorophylls and carotenoids of the lettuce. The marketable sensory characteristics (shape, and color) of fresh plants were also evaluated.(Lactuca sativa crispa. “Lollo bionda”) lettuce were cultured in three levels of vertical hydroponically for 45 days under different light sources of natural light in the upper level, 60% shade light in the middle level and red (R), green (G) blue (B), provided by light-emitting diodes (LEDs) was 12/12 (day/night) in the lower level. Three levels of vertical hydroponics were also prepared in the same levels of three treatments, while were exposed to natural light as a control group.For treatments, lettuces exposed to natural light, with high light intensity, showed the highest values in all growth parameters as well as pigments, while lettuce under the 60% shade, the result showed all pigments and growth parameters were low, except the length was similar to the length of the natural light treatment. As for the lettuce exposed to the (RGB) LED, which recorded lowest light intensity, was a significantly lowest value at all growth parameters, while pigments not detectable.As for the control group, all of which were exposed to natural light, where the light quality was equal, while the light intensity was decreased gradually from top to bottom. The values of the parameters were high at all levels. With noted that, the leaf area was the highest in the middle level, while the fresh and dry weight were highest at the upper level. As for the pigment values, where all were high and no significant difference.Lettuce Plants under natural light looked large, vigorous, most compact morphology with dark green leaves, while those under 60% Shade and (RGB) LED treatments looked small, weak, sparse and fragile.The overall results indicate that all levels of treatments and control group obtained the same qualities of light in terms of spectra radiation, which the required for plant growth, but the different quantities of light spectra radiation were the main parameter in the greenhouse in the experiment, which led to significantly different results.These new strategies to exploit the quality and quantity of solar natural light in the vertical hydroponics system should be conveyed for vegetable production in the UAE.

Download or read book Efficient Nitrogen Fertility and Drip Irrigation Management in Commercial Lettuce and Celery Production written by Shane Joseph Breschini and published by . This book was released on 2001 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Nutrient Concentration and Growing Seasons on Growth Yield and Quality of Leafy Lettuce Lactuca Sativa L in a Hydroponic System written by Thikanang Silence Chiloane and published by . This book was released on 2012 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Air and Root Temperature Effects on Growth of Lettuce Lactuca Sativa in Deep flow Hydroponic Systems written by Helen Christine Thompson and published by . This book was released on 1997 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: