Hydroponic is a technology for growing plant in nutrient solutions (Water containing fertilizers) with or without the use of an artificial medium (sand, gravel, vermiculite, rock wool, perlite, peat moss, coir or sawdust) to provide mechanical support (Jensen and Collins, 1985). Hydroponic systems are further categorized as open (i.e. the nutrient solution delivered to the plant roots, is not reused or closed (i.e. surplus solution is recovered, replenished and recycled).
The earliest record scientific approach to discover plant constituents was in 1600 when Belgiun Jan Van Helmont showed in his classical experiment that plant obtain substances from water (Resh, 1985). In 1804 De Saussure proposed that plants are composed of chemical elements obtained from water, soil and air (Douglas, 1983). Various research Workers had demonstrated by that time that plants could be grown in an inert medium moistened with a water solution containing minerals required by the plants (Shive, 1938; Hoagland and Arnon, 1950; Armon, 1950; Schwartz, 1968 and Resh, 1985). Nutrient film Techniques (NFT) is the earliest method of hydroponic. Allen Cooper (1965) at the Glasshouse Crop Research Institute on Littlehamptan, England Poineered work on NFT cropping. The sufficient oxygen would be supplied to the plant root by this system. Capital cost and complexity of operation the system can be reduced by use of NFT system.
Tomato is the second most widely grown vegetable crop in the world and most
popular vegetable in Bangladesh. It is rich in Vitamins A, C and contains the
antioxidant lycopen (Jones, 1998). Tomato, which was once productive in Bangladesh
has gradually decrease its yield and production largely due to limited cultivable
land and primitive culture processes. As a result loss of production and growth
occur, nutrient deficiencies and culture techniques can be recognized which
ultimately affected yield.
Great amounts of tomato yield are devastated by proper culture techniques. Here soilless culture is the important method to increase yield of tomato.
Growing hydroponic vegetables is one of the most exacting and intense forms of all agricultural enterprises and becoming increasingly popular. It is highly productive conservative of water and land and protective of the environment. For production of tomato, hydroponic is common in world (Maloupa and Gerasopoulos, 2001).
Hydroponic is a very young science for commercial tomato production. It is a valuable means of growing fresh vegetables. It is therefore necessary to best the possibility of tomato production through water and sand culture. This research program was undertaken to evaluate the water and sand culture for commercial production of tomato in Bangladesh condition.
Materials and Methods
The research work was conducted in the Botanical Garden, Rajshahi University,
Bangladesh during the period from November 2000 to August 2001. The area covered
for conducting each experiment was 25.86 sq. m. Two cultivars of tomato: Kingkong
and Egg tomato were tested. Inorganic fertilizer salts including macro and micronutrient
were used in the present study. Tube well water was used for both NFT system
and sand (0.6 to 1.5 mm diameter, collection from local padma river) culture
as the growing medium.
||Composition of Resh (1985) nutrient solution in ppm concentration
|A = for seedling (10 to 14 days old)
|B = for 14 to 16 inches height until
|C = for mature plant
||Lay out of the experimental field of NFT system
|| Lay out of the experimental field of sand culture
Some equipments were also used for experimental setup e.g. PVC pipe, Polyethylene
paper, hoose pipe, tank, water pump, timer clock and soil tub.
Nutrient composition was prepared followed by Resh (1985) as shown in Table 1. During preparation of nutrient medium macronutrients were dissolved first followed by micronutrient and pH was adjusted in 6. Plastic ice cube trays were used for growing transplants.
In NFT structure 20.32 cm diameter PVC pipes were placed on the concrete with 60 cm distance between them. The acceptable slope was about 1 in 100. Seedlings were placed in hole on the PVC pipes tighten with foam. Two reservoir tanks were used for supplying nutrient solution. For continuous circulation of solution, pump machine and timer were used in the set up. The nutrient solution was preserved in tank-1 from where it was pumped in to tank-2, then back to tank-1 after required hrs. For fresh supply of the nutrients, the solution was changed after every two weeks up to final harvest.
The sand culture device is shown in Fig. 2. It consists of one nutrient tank connect with main supply pipe, which is linked with several feeder pipes. The feeder pipes have many pores under which one plant carrier is placed. The solution is dripped through the pore of the feeder pipe in such way that the extra amount of solution will be drained out through to side pore of the plant careers and eventually the sand will be in moist. The nutrient was supplied from the tank once or twice in a day depends upon the relative humidity of air.
Results and Discussion
Water culture: Standard error of all characters was less than the corresponding
mean as expected. High value of SE was observed for fruit weight in respect
of season and variety. Where as, low SE was noticed in stem girth (Table
2). The items cultivar and cultivar x season (CXS) were significant for
all characters. The item season was significant for leaf number, root length,
fruit number and fruit weight but was non significance for plant height, leaf
length, stem girth and branch number. The LSD data reveal that the cultivars
Egg tomato and Kingkong were different from each other for the characters plant
height, leaf number, leaf length, stem girth, branch number, root length, fruit
number and fruit weight. Seasonal difference was observed for the characters
leaf number root length, fruit number and fruit weight. Regarding varietal performance
in winter and summer seasons, Kingkong produced fruits only in winter seasons.
Where as, egg tomato produced fruits in both the seasons but summer was found
Sand culture: Standard error of eight characters was less than the corresponding
means. Here also the highest and lowest SE was observed for weight respectively
(Table 2). For variance analysis the items cultivars and C
x S were significant for all characters. But the item season was significant
only for plant height, leaf number, leaf length, root length, fruit number and
fruit weight (Table 3).
|| Means with standard error (SE) for eight characters of tomato
plant in water and sand culture
The calculated LSD shows that Egg tomato was significantly different from Kingkong
for all characters. Regarding varietal performance similar trend like NFT was
A soilless medium must provide O2 for plant root just as does soil. In NFT system film flow of solution could provide this (Cooper, 1973). In sand culture although the nutrient solution was not recycled. Fine particles (0.6 to 1.5 mm) allow lateral movement of water through capillary action, so that solution applied at each plant become evenly distributed though out the root zone (Resh, 1985). pH of hydroponic nutrient solution is very important. Both the culture pH of the solution was controlled in 6 level. High pH (more than 7.0) caused precipitation of Fe++, Mn++, PO4, Ca++ and Mg++ to insoluble and unavailable salts (Resh, 1985). Willumsen (1980) was adjusted pH of the flowing nutrient solution with 4.5, 5.5 and 6.5 levels and he concluded the difference in pH level did not directly the tomato yield.
The cultivars performed differently with the change of season. Kingkong performed
well in winter season, where as Egg tomato performed well in summer season,
in respect of culture medium.
|| Analysis of variance for eight characters of tomato plant
in water and sand culture
There are reports on different types of GxE interaction in different crops
by several investigation (Ananda, 1968; Nandipuri et al., 1971; Singh
and Singh, 1976; Islam et al., 2000).
NFT produced slightly higher yield than sand culture for the studied two cultivars. Mancini et al. (1994) also found that higher yields of Chinese cabbage were obtained in NFT than sand culture. Similarly Ismail and Ahmed (1997) reported that plant growth and yield were better in NFT compared to sand culture grown plants in tomato. The highest yield was obtained from plant grown on Kingkong cultivar in winter season of NFT (2.4 Kg/plant). Tuzel et al. (2001) were also found higher yield in perlite peat (7.4 kg/plant). But we found sand culture was seemed to be simple and cheaper than the NFT system. The devices and techniques are used in this experiment for both water and sand cultures are found to be suitable for soilless culture of tomato in Bangladesh includes other countries in tropical Asia.