Soil fertility status determination of the proposed agricultural experimental field of the Asian Inst. of Technology [Thailand]
1984
Basnet, B.B.
Soil samples were taken from the proposed agricultural experimental field of the AIT campus, which was laid-out into 108 plots of 400 sqm each. One hundred and twenty-four soil samples (one composite sample from each plot plus duplicate samples from 16 plots) were analysed for seven different soil parameters. The field appeared to be very acidic. Electrical conductivity of the soil varied from 136-1515 micromhos.cm-1. The organic carbon content of this mineral soil is within the range of 0.73-1.91 percent. The soil is well represented with its available potassium content of 158-311 ppm. However, it is found to be very poor in its available phosphorus, which is but typical for this highly acidic acid sulphate soil. Although the available P ranges from 2.6 to 19.85 ppm, most part of the field has very low available phosphorus. A wide range of "available" sodium was encountered within the field. Lime requirement for individual samples was determined by different methods. The SMP single buffer and Ca(OH)2 equilibration method resulted almost in double the amount of lime requirements estimated by exchange acidity and exchangeable aluminum methods. Ca(OH)2 equilibration method, although it estimates reasonable amount of lime quantity, is too lengthy for serial analyses. SMP single buffer method is quick and resulted in values close to the Ca(OH)2 equlibration test. Fertility contour maps have been draw using SPSS - package to show the heterogeneity of soil
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