Effects of Tridymite, Yod Doi and Boom Khamtorn Soil Conditioners on Physical and Chemical Properties of Soil and Rice Yield

Abstract

A study was made to determine the effects of Tridymite, Yod Doi and Boon Khamtorn soil conditioners on physical and chemical properties of soil and yield of RD 23 rice variety on a sandy soil at Ubon Ratchathani Rice Research Centre in 1998-2000. A randomized complete block design comprising 6 treatments with 4 replications was investigated. The control and chemical fertilizer treatments were also included to determine the effects of the soil conditioner treatments. The six treatments namely 1) control, 2) 37.5 kg (16-16-8, N-P₂O₅-K₂O)/rai, 3) 75.0 kg (16-16-8, N-P₂O₅-K₂O)/rai, 4) 37.5 kg (16-16-8, N-P₂O₅-K₂O)/rai + 9.4 kg tridymite/rai at different depths were determined prior to planting of the first crop and after harvesting of the third crop, while rice yield was yearly determined. After 3 consecutive years results were indicated that the physical soil properties at the 0-10 and 10-20 cm depth (bulk density, hydraulic conductivity and plant available water) were not significantly different among treatments (P<0.05) as well as the chemical properties of the soil at the respective depths (pH, organic matter and available phosphorus) except exchangeable potassium. The three – year average of rice yield was in favour of sole utilization of chemical fertilizer grade 16-16-8 (N-P₂O₅-K₂O) at the rate of 37.5 kg/rai and its combination with tridymite at the rate of 9.4 kg/rai were 213 and 199 kg/rai respectively (P<0.05). Meanwhile, the utilization of Boon Khamtorn tended to give higher rice yield (180 kg/rai) than did the Yod Doi soil conditioner (170 kg/rai) and it was also control treatment (145 kg/rai) (P<0.05). Then, the utilization of tridymite increased the price of input while the output or the yield of rice remained the same. As the utilization of Boon Khamtorn and Yod Doi soil conditioners tended to improve the yield of rice in long term.