Regional Distribution and Evolution Characteristics of Soil Available Phosphorus in Guangdong Tobacco-growing Areas

The purpose of this study is to clarify the present situation and evolution characteristics of soil available phosphorus in Guangdong tobacco-growing areas. The content of available phosphorus in different production areas and different types of soil in 2000 and 2012 were determined by comparative analysis. The results showed that the average content of available phosphorus in soil was 44.92 mg/kg in Guangdong tobacco-growing areas, it was at the "surplus" level as a whole, with 31.75% and 13.02% of soil available phosphorus content at the levels of "surplus" and "deficiency", respectively. The soil available phosphorus contents in Shaoguan, Meizhou and Qingyuan areas were 29.03, 122.61 and 22.61 mg/kg, respectively, in which Shaoguan and Qingyuan areas were at the "rich" level, Meizhou production area was at the high "surplus" level. The average soil available phosphorus contents in purple soil, beef live field and sand mud field was 15.43, 31.95 and 74.34 mg/kg, at the "moderate", "rich" and "surplus" levels, respectively. During the 12 years (2000-2012), the soil available phosphorus contents in the whole province, and in Shaoguan and Meizhou tobacco-growing areas were increased by 3.89, 10.64 and 97.27 mg/kg respectively. For the different soil types, that of purple soil, beef live field and sand mud field were increased by 5.53, 12.19 and 46.97 mg/kg, respectively. Therefore, the soil phosphorus management in Guangdong tobacco-growing areas was recommended as the following:to apply phosphorus fertilizer every other year in Meizhou tobacco-growing areas and in sand mud field, to reduce phosphate fertilization by half in beef live field, and to apply phosphate fertilizer normally in other types of soil, which could promote the sustainable development of high-quality tobacco leaf production and protect the ecological environment of the tobacco-growing areas.