Effects of recycled bentonite addition on soil properties, plant growth and nutrient uptake in a tropical sandy soil
- 341 Downloads
The only way to increase the low CEC of sandy tropical soils over the long term is to apply high CEC materials such as 2:1 clay minerals. Acid activated bentonite is used in Thailand in the vegetable oil industry during the clarification process. The waste bentonite is discarded afterwards. The aim of the study was to compare the effects of the addition of these oil bentonites (OB) with the addition of cation beneficiated bentonite (BB) on soil properties and plant growth. Palm, rice and soybean OB, and bentonite beneficiated with calcium, magnesium, and potassium were applied at rates between 5 and 40 t ha−1 to an Arenic Acrisol. Three consecutive crops of sorghum were grown in pots. Biomass and plant nutrient content were determined at each growth phase, and selective soil properties were measured at the start and the end of the study. Beneficiated bentonite was not water repellent, but the addition of OB resulted in soil water repellency. The application of bentonite at the rate of 40 t ha−1 increased the cation exchange capacity (CEC) from 0.6 cmolc kg-1 in the control to 1.9 and 0.7 cmolc kg−1 in the BB and OB, respectiveley. The lower value of the CEC for OB compared to BB was probably due to the activation process and oil coating. OB applications at rates higher than 20 t ha−1 did not increase biomass, and biomass decreased with increasing water repellency. The other treatments produced a higher biomass than the control. However biomass was below potential because of widespread nitrogen deficiency. Exchangeable K was exhausted in two crops, whatever the initial level, stressing the issue of K management in this soil type. Soybean OB is a promising material for soil chemical properties and biomass production, probably because of its low oil content.
Key wordsacrisol bentonite CEC plant nutrition rehabilitation Thailand
Unable to display preview. Download preview PDF.
- Blake G R and Hartge K H 1986 Bulk density.In Methods of Soil Analysis. Part 1-Physical and mineralogical methods. Ed. A Klute. pp 363–375. SSA book series, 2nd edition.Google Scholar
- Driessen P, Deckers J, Spaargaren O and Nachtergaele F 2001 Lecture notes on the major soils of the world. FAO World Soil Resources report num. 94, 334 pp.Google Scholar
- Gillman G P and Sumpter E A 1986 Modification to the compulsive exchange method for measuring exchange characteristics of soils. Aust. J. Soil Res. 24, 61–66.Google Scholar
- Imsamut S and Boonsoppan B 1999 Established soil series in the north-east of Thailand. Reclassified according soil taxonomy 1998. Report Department of Land Development (Thailand), 154 pp.Google Scholar
- Kheoruenromne I and Suddhiprakarn A 1984 Ecology, classification and effect of management on selected sandy soils in Thailand.In Ecology and management of problem soils in Asia. pp. 208–222. Food and Fertilizer Technology Center for the Asian and Pacific Region, Books series no27, Taiwan.Google Scholar
- Kheoruenromne I, Suddhiprakarn A and Kanghae P 1998 Properties, environment and fertility capability of sandy soils in northeast plateau, Thailand. Kasetsart J. 32, 355–373.Google Scholar
- Noble A D, Gillman G P and Ruaysoongnern S 2000 A cation exchange index for assessing degradation of acid soil by further acidification under permanent agriculture in the tropics. E. J. Soil Sci. 51, 233–243.Google Scholar
- Ragland J and Boonpuckdee L 1987 Fertilizer responses in northeast Thailand: 1. Literature review and rationale. Thai J. Soils Fertil. 9, 65–79.Google Scholar
- Reuter D J and Robinson J B, 1997 Plant analysis. An interpretation manual. 2nd edition. CSIRO publishing, Collingwood, Australia. 572 p.Google Scholar
- Virta R L 2001 Clays: U.S. Geological Survey Mineral Commodity Summaries 2000. 2 pp.Google Scholar