1 Institute of Horticulture，Chengdu Academy of Agriculture and Forestry Sciences，Chengdu 611130，Sichuan，China； 2 College of Resource Sciences & Technology，Sichuan Agricultural University，Chengdu 611130，Sichuan，China
Abstract：Pengzhou City is a main garlic producing area in Sichuan Province．The annual head of garlic output is about 80 thousand-100 thousand tons．Recently，there occurred obvious obstacle in garlic planting areas，mainly for‘seedling death’．This experiment collected respectively the soil samples from garlic planting obstacle areas and garlic normal growth areas in Pengzhou City；analyzed their basic chemical properties；and carried out hydroponic experiments at the same time，aiming at finding out the major soil factors causing garlic planting obstacle．The results showed that the soil from garlic planting obstacle areas in Pengzhou City was acidified obviously．The contents of exchangeable acid，exchangeable H+ and Al 3+ in soil increased significantly．The hydroponic experiments further confirmed that the pH of soil extract liquid and Hoagland nutrient solution was the main factor affecting garlic root system growth．When the nutrient solution pH was less than 5.0，the garlic root system growth was suffocated．While，when the nutrient solution pH was less than 4.0，the garlic root system could not form．Apparently，soil acidification is the main reason for garlic planting obstacle in Pengzhou City．
