The soil nutrition and fertility have been analyzed following different preceding crops and at different altitudes in Fuyuan County. The results showed that the total contents for both potassium and phosphorus were generally low at all altitudes,below an average medium-low level. To determine the effect of previous crops on tobacco soil nutrition and fertility,various crops were grown prior to tobacco production at three altitudes( low,middle,and high). At low altitude( 1 700 m),the highest level of soil fertility was observed following a p...