Abstract: By the method of PCR-DGGE, this paper studied the effects of rotation with wheat, soybean, villose vetch, clover, and alfalfa and intercropping with onion and garlic on the bacterial communities in rhizosphere soil of cucumber. The results showed that rotation and intercropping with test plants increased the diversity and evenness indices of bacterial communities in cucumber rhizosphere soil, and also, cucumber yield. The sequencing of DGGE bands indicated that most of the bands had high homology with uncultured bacterial species, and were of Sphingobacterium and Proteobacteria. High bacterium G+C was only detected when cucumber was intercropped with onion. The diversity of soil bacterial communities varied with the growth stages of cucumber, being the highest at vigorous fruiting stage. It was suggested that intercropping with onion and rotation with wheat were the best cultivation modes of cucumber.

Key words: climatic change, Changbai Mountain Nature Reserve, normalized difference vegetation index (NDVI)