Effect Of Different Cropping System On Tobacco Growth And Soil Quality

In the case of gradual reduction of cultivated lands in our country year by year, however, continuous tobacco cropping is quite common in this region, which produces a series of cultivation problems. These negative multiple effects could be unbeneficial to sustainable tobacco production in this area. At present, there are many researches on continuous cropping obstacles, but no consistent conclusion. The research objects are mainly focus on soybean, and the study is still not deep enough for tobacco. Therefore, this study aims to systematically study the effect of continuous cropping on soil nutrients and microbial. The main conclusions are as follows:1Continuous cropping in tobacco significantly affected the number of soil microbes in soil. The number of soil bacteria and ammonifying bacteria and nitrifying bacteria in wheat/tobacco was the most, followed by tobacco continuous cropping for2years, and the least was occurred in tobacco continuous cropping for6years. The number of soil actinomyces and fungi was the least in wheat/tobacco, followed by tobacco continuous cropping for2years, and the most was occurred in tobacco continuous cropping for6years.2Continuous cropping significantly affected the growth of tobacco. Continuous cropping significantly inhibited the top flower, middle and upper leaf of flue-cured tobacco quality, tobacco stem biomass, root elongation and root weight, and with the increase of continuous cropping time inhibitory effect more obvious.3Compared with continuous cropping system, there had much higher soil pH value, soil organic matter content, soil available nitrogen, available phosphorus and available potassium content in rotation cropping system. So, it suggested that long-term continuous cropping is not conducive to the decomposition of soil microorganisms on the existence of nutrients, and it can affect the external validity of fertilizer.4Rotation can significantly improve the growth and development of tobacco plants. Investigation of the storage period showed that, the plant height, leaf area, leaf area index, pitch and the root dry weight in crop rotation treatment were better than that of continuous cropping treatment. The yield and economic benefit of tobacco, yield and output value of rotation increased significantly in crop rotation treatment, because the rotation can improve the quality of the soil, promote the growth and development of tobacco plant good, quality of tobacco leaf was obviously higher than that of continuous cropping.