>It does not go into the electrostatic behaviour of clay particles. Nor does it cover the degree drying out when wilting occurs, reducing transpiration), and remaining soil moisture serves to maintain plants in drought mode. That period of semi-dryness so important for bulbs lasts longer in small particle soils than in granular, when soils are drying out and bulbs are 'dormant' I think I’ve read that before, and it makes perfect sense, but .....in a climate with 100 cm of precipitation spread throughout the year. It fails to take into account the evaporative potential of intense sunlight coupled with low humidity, and long periods of drought. That’s why the “inverse texture effect” has been proposed to explain the greater water-delivering efficiency of coarse-textured soils in semi-arid and arid regions. Most of the water is delivered by thunderstorms. I’m not aware of any studies that have been done on the ecology of plants (like bulbs) adapted to heavy soils and extended drought. Are there any? Bob Nold Denver, Colorado USA _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://pacificbulbsociety.org/list.php http://pacificbulbsociety.org/pbswiki/