Development of soilless culture for crop production at Chitralada palace

Objective of this project has been to develop the best possible substrates and soilles culture techniques for horticultural crop production in Thailand. The study was started to gain experience and knowledge by using natural organic materials readily available in Thailand and sand for growing crops with simplified procedures which are within the financial and technical resources of the small farmers in rural areas. The main substrates used were mixtures of rice hulls, coconut coir and sand. The results showed that a wide range of horticultural crops could be grown in soilless substrates. Many different substrates were tested, the best of these in terms of plant performance and yield being a combination of rice hulls, sand and coconut coir (1:1:1 v/v), provided that the coir had been well weathered beforehand. Among the crops grown, bush-type tomatoes, var. sauce peto were fruiting well, averages 30 fr. and 2,092.6 g/pl, though a cultivar with the indeterminated habit was clearly beyond its temperature tolerance range. The fruit of musk melon var. bonus grown in this mixture could be harvested between 48-50 days from pollination. The averages of fruit weight were 1,100 g/fr and total soluble solids 13-15 percent brix. A fully automated system for crop production in re-circulating solution culture had also been assembled and tested. This was used to gain operating experience of advanced hydroponic systems as a basis for possible future developments, Such systems, which are costly, could only be justified if crop yields under prevailing environmental conditions were sufficiently high to match the considerable capital expenditure. The results showed that the same variety of musk melon was successfully grown in hydroponic system (nutrient film technique, NFT). Days from pollination to harvest were 38-47, the fruit weight 1,100-1,300 g/fr, soluble solids 11-13 percent brix. Lettuce and Chinese celery were alternatively grown for crops each in a re-circulating hydroponic system during June 1991-May 1992. The results showed that the fresh and dry weights of lettuce and Chinese celery were 56.67, 7.04 and 31.27, 5.31 g/pl, respectively. The average yield of lettuce was 4.5 and Chinese celery 7.81/sqaure m. The estimated cost of production was 38.48 for lettuce and 70.64 Baht/square m for Chinese celery. Sand culture of coriander (Coriandrum sativum Linn.) was carried out between January and February 1993. The average yield, fresh and dry weights were 2.95 kg/square m 22.75 and 2.09 g/pl, respectively. The estimated cost of production was 35.3 Baht/square m.