Leaf area is important for estimating biomass productivity, adaptation to the environment, nutrition, and soil-water relations. It also plays an important role in determining the proper application rates of insecticides and fungicides. Image processing is considered one of the best methods for estimating the leaf area of a plant as it is inexpensive and saves time. In the image processing method, leaf area is calculated through pixel number statistics by counting the number of pixels in the leaf area region of digital images. In this study, a simple system based on image analysis using the ImageJ software application was developed to estimate cotton leaf area. Two hundred and forty Egyptian cotton (Giza 86) leaves were captured using a digital camera. These leaves were collected randomly from different heights and different fields at Kafer El-Dawar center, El-Behera

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In this study, a complete solar water heating system has been located beside two experimental greenhouses cultivated by sweet coloured peppers crop from 27 th of August 2010 until 26 th of July 2011. The total heat energy required for heating the greenhouse was computed based on the requirements for heating a greenhouse reside in the task of adding heat at the rate at which it is lost. One greenhouse equipped with a complete solar heating system (two solar collectors, heat distributing system, and storage tank) connected to biomass burning unit as an auxiliary heater. Another greenhouse was connected to a complete solar heating system equipped with electric heater as an auxiliary heater to compare and investigate how much heat energy can be provided when using the renewable energy for greenhouse heating in winter and cold days. The thermal performance analysis of the solar heating system was experimentally determined, by measuring the temperature increase at various water inlet temperatures and intensity of solar radiation, under clear sky conditions. The daily average overall thermal efficiencies of the solar collector and the storage system during the experimental period were 76.39% and 93.17%, respectively. During the 181 days heating season, the solar panels collected 3922 kWh of energy which provided 47.74% of the total heat energy required to heat the greenhouse (8215 kWh). The hybrid system (biomass burning and solar energy systems) provided 46.585 kWh (85.90%) of the daily total heat energy required (54.230 kWh). While, the solar heating (solar and electric energy) system with greenhouse 2 only provided 20.223 kWh (38.32%) of the total heat energy required (52.778 kWh). Due to the microclimatic conditions of the greenhouse were at or around the desired level, the sweet coloured pepper had have optimal vegetative growth rate, stem length, number of fruits being seated, and fresh yield. The total costs per square meter of greenhouse were L.E. 57.01.The fresh yield of sweet coloured peppers was 6.595 kg/m 2 , which sold by L.E. 79.14, consequently, the estimated return on capital was 38.82% per annum.

An direct solar-electrical dryer has been designed and constructed at a Zagazig City of , Sharkia governorate, Egypt. Solar dryer consists of solar flat plate air collector with V-corrugated absorption plate in conecation with drying tray uint. The red onions most popular to consumer no dayes in the Zagazig City so that it was chosen to experiment. The new dryer prototype was tested its efficiency for drying red onions slices 5 &10 mm to study the effect of drying air velocities (0.4,0.5 and 0.6 m/s) at air temperature (40.82,42.37 and 43.81)respectiviely.The qualitative analysis for drying of onions slices 5 mm showed that initial moisture content of about 88% (wet basis) was reduced to final moisture content of about (10%,12% and 16%) for velocities (0.4,0.5 and 0.6 m/s),while it were (16%,18% and 20.8%) for onions slices 10 mm respectiviely.The average percent of dryer efficiency was found to be 16.07, 12.83 and 12 % for air speed 0.4,0.5 and 0.6 m/s respectiviely. In order to estimate and select the suitable form of solar drying curves, five different mathematical models, were compared according to their coefficient of determination R 2 , MBE, RMSE, %E and chi square X 2 to estimate experimental drying curves. The page and Modified page II model in this condition proved to be the best for predicting drying behavior of red onions slices 5 and 10 mm with (R 2 = 0.9961 and 0.9899) and (X 2 = 0.000121 and 0.000423).The effective moisture diffusivity (Deff) was obtained using Fick's diffusion equation and its value varied from 1.46× 10 -9 to 1.59× 10 -9 m 2 /s and 5.25× 10 -9 to 5.72× 10 -9 m 2 /s. The temperature dependence of the diffusivity coefficients was described with the activation energy (Ea) value of 21.33 kJ/mol and 19.14 kJ/mol for red onions slices 5 and 10mm.Finally an economic evaluation was calculated using the criterion of payback period which is found very small 1.84 years compared to the life of the dryer 25 years.

In the present work, a new special, prototype of an indirect solarelectrical dryer for agricultural products was set up and also tested at