Studies On The Regional Difference In Organic Matter Of Tobacco Soils And Their' Are Fertility In Hunan Province

The regional differences of tobacco-growing soil organic matter (O.M.) had obviousvariation in Hunan, but different soil O.M. content had a little effect on the growth andthe development of flue-cured tobacco. In order to prove up the reasons, the regionaldifferences of soil O.M. and the active organic carbon were analyzed. The main resultsobtained were as the following:1 The results showed that KMnO₄ oxidation shaking method was better with highrepeatability, lower coefficient of variability and reliable testing value than the othermethods. This method was easily and quickly to operate.2 Soil O.M. content ranged from 17.22 to 53.31 g/kg, the average of O.M. was 33.81g/kg. Soil O.M. was the highest in the southem of Hunan with average O.M. 43.12 g/kg,followed by the middle of Hunan with average O.M. 31.91 g/kg, and in the western ofHunan with average O.M.23.48 g/kg was the lowest. Soil O.M. had a significantdifference at different tobacco production areas. The soil active organic carbon (SAOC)ranged from 2.60 to 5.92 g/kg and the average content was 4.17 g,/kg. The SAOC was thehighest in the southern of Hunan with average SAOC 4.64 g/kg, followed by the middleof Hunan with average SAOC 3.79 g/kg, and in the western of Hunan with averageSAOC 3.55 g/kg was the lowest, but it had no significant effect on different regionalareas. There was significant difference of proportion of SAOC to total organic carbon.3 The correlation between SAOC content and soil O.M. was very significant. Thecontent of soil O.M. can not respond the effect and contribution to the soil nutrient byorganic matter completely. So the SAOC was one of most important factors on the growthof flue-cured tobacco.4 The effective B showed a very low level with the content of 0.2 mg/kg, about 96%soils were short of this nutrient. Different districts showed big differences in nutritioncontents and their distribution characteristics. Southern part showed higher N, P, Zncontents, with numbers of 226.3 mg/kg,25.89 mg/kg, and 2.97 mg/kg respectively.78.7%soil was short of effective k with a mean content of 92.5 mg/kg, and 36.7% soil was shortin Mn supply in this district. For western part, the effective N and P showed power levelwith the numbers of 120.0 mg/kg and 8.52 mg/kg. 36.28% and 62.8% soils were short ofP and Zn respectively in this region. K and Mn were affluent in this district with the content of 176.48 mg/kg and 37.5 mg/kg respectively. Mg was seriously short in soils ofeastern parts.