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Soils
The extremely variable topography of the country is associated with a complex mosaic of soils.

The Coastal littoral, located between the Pacific Ocean and the western Andes possesses an abundance of hydromorphic soils particularly in the well-watered parts, which have moderate to low drainage, and moderate fertility. It contains soils derived from deposits of diverse origins influenced by volcanic activity of the Andes, aeolian transport of volcanic ashes and alluvial deposits, all subjected to intense weathering.

In the temperate Andean ecozone (see below under ecozones), soils vary somewhat depending upon rainfall. It should be noted that classification of Andean soils is notoriously complex; details and equivalencies between systems of classification are available (Quantin, 1986; FAO, 2001; FAO-CSIC, 2002). The portion of the temperate area frequently classified as a low montane spiniferous steppe, with rainfall of less than 500 mm includes the following soils (León-Velarde and Izquierdo, 1993): (a) Durandept, sandy loams, with a calcareous layer located above a duripan placed at a depth of 70 cm - these are soils that if irrigated support a variety of annual crops, lucerne, oats and Kikuyu grass; (b) Durustoll, generally located on slopes, over fine ashes and also with an underlying duripan; (c) Eutrandept, loamy soils with very fine ash, low water retention, pH 7; and lastly (d) Torripsamment, very sandy soils, with less than 1 percent organic matter and pH 8. Farms surveyed in this area by Ramírez et al. (1996) had soils with pH 5.2 to 6.7, acidity increasing with altitude, generally low in organic matter (OM), and always very low P (< 4 ppm). When rainfall increases to 500-1,000 mm, the zone is classified as low montane dry forest, and includes very variable soils, most frequently derived from volcanic ashes. These are clayey loams, black soils, that support productive stands of lucerne if irrigated. The low montane humid forest zone is encountered in areas with 1,000 to 2,000 mm, and has similar soils to the previous one.

http://www.fao.org/ag/agp/AGPC/doc/Counprof/Ecuador/ecuador.htm#solis

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How to grow Trichocereus peruvianus

... A soil ph of between 6.1 and 7.8 is ideal for Trichocereus peruvianus as it does best in weakly acidic soil - weakly alkaline soil...

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nicechrisman said:

I've never known many cactus growers to worry about it too much. Most I know throw some lime down once a year or so though.

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