Effect of continuous cropping on soil nutrients at flue-cured tobacco rhizosphere and non-rhizosphere

Abstract

In order to clear the effects of flue-cured tobacco continuous cropping on soil nutrients, soil chemical properties in rhizosphere and non-rhizosphere at different continuous cropping years of flue-cured tobacco were analyzed. The results showed that pH both at rhizosphere soil and non-rhizosphere soil, and soil organic matter in non-rhizosphere soil decreased firstly and then increased at different growth and development stages of flue-cured tobacco during continuous cropping years. However, the content of organic matter in rhizosphere increased gradually. The total N and available N both in rhizosphere soil and non-rhizosphere soil, and total K and available K in non-rhizosphere soil showed the trend from decrease to increase, and then decrease again. The total K and available K in rhizosphere, the available P both in rhizosphere and non-rhizosphere soil, and the total P in rhizosphere increased firstly and then decreased. However, the total P in non-rhizosphere soil decreased gradually. With the increase of continuous cropping time, the pH both in rhizosphere and non-rhizosphere soil decreased gradually, however, the contents of organic matter, total N and available N, P and K both in rhizosphere and non-rhizosphere soil appeared to enrichment at different degrees. The pH at rhizosphere soil was lower than that at non-rhizosphere soil, however, the content of organic matter, total N and available N, P and K in rhizosphere soil were higher than those in non-rhizosphere soil. Continuous cropping of flue-cured tobacco changed a reasonable proportion of available nutrients both in rhizosphere and non-rhizosphere soil, which could not meet the vast demand for the growth of flue-cured tobacco. Compared with available N and P, continuous cropping resulted in the lack of available K in rhizosphere soil and the enrichment of available K in non-rhizosphere soil.