| The soils of greenhouses in Nianbo Town of Ledu County in Qinghai Province were used as samples, and
analyis was made of the content of salt and nutrients in soils with different planting yearsof 1, 2, 5，8, 10，15, 22 and 25 ~ 27. The results showed that the the salt content increased with the increase of cultivation years, and the increasing rate ranged from 62.26%~404.72% in contrast with the control; while with the increase of cultivation years, pH de-creasing rate ranged from -6.70%~- 2. 15%; and they had opposite trends; The contents of organic matter, total ni-trogen and total phosphorus were significantly higher than the control， and the increasing rate ranged from 83.84%~213.13%, 58.45%~164.86% and 77.99%~243. 40% respectively compared with the control; The content of available nitrogen also increased，and the increasing rate was from 39.70%~139.38% compared with the control; The available phosphorus changed fluctuately，and the changing rate was between -65. 81%~47.44% compared with con-trol. |