Evaluation of Nutrient Film Technique and Sand Culture for Year-round Production of Tomato (Lycopersicon esculentum Mill.) in Tropical Asia

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.

Table 1:	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

Fig. 1:	Lay out of the experimental field of NFT system

Fig. 2:	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 conducive.

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).

Table 2:	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 also noticed.

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.

Table 3:	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.