Abstract:

To explore the effects of different organic materials on the root characteristics and the aboveground part NPK accumulation of flue-cured tobacco, the effects of three organic materials, namely steam explosion straw, peat and biochar, on the physical and chemical properties of the tobacco soil, tobacco root characteristics and the aboveground part NPK accumulation were investigated in a pot experiment with ‘Yunyan 87’ as the material. The results show that the physical properties of tobacco plant soil, such as soil bulk density and total porosity, are significantly improved by the addition of organic materials, especially biochar and peat. The root length density is greater in the lower soil layer and soil farther from the main root axis, and the development of primary lateral roots and adventitious roots is better under biochar or peat treatment compared with those under steam explosion straw treatment. Organic matter, alkaline N, available phosphorus and available potassium content in the soil are significantly increased after organic material treatment, with the most obvious effect observed in biochar and peat treatment. The typical correlation between root characteristics and plant NPK accumulation shows that there is a positive correlation of 0.999. Organic materials could improve soil properties, increase effective nutrient content, promote root development, deep rooting and diffusion, and increase the aboveground part NPK accumulation, with the most significant effect of biochar treatment, followed by peat treatment.

Key words: flue-cured tobacco, organic material, soil physical and chemical properties, root characteristics, NPK accumulation.