大理州植烟土壤肥力质量现状与演变趋势

在大理州乡镇、村、户典型的连片烟田作了调查访问,并采集了506个耕层土样进行系统的化验。结果发现,本州植烟土壤肥力质量的主要指标有蜕化的趋势,土壤有机质平均27.7 g/kg,有下降趋势;pH平均值6.47,呈酸化趋势;有效磷P₂O₅平均27.23 mg/kg,老烟区已累积偏高,且有继续上升趋势,对烟叶生产不利;速效钾K₂O平均189.15 mg/kg,总体水平较高,有上升趋势,但也有水平偏低的;交换性镁Mg平均139.5 mg/kg,约一半土壤偏低;速效硼B0.31 mg/kg,普遍缺乏或偏低;有效钼Mo平均0.24 mg/kg,约1/3缺乏;速效硫、钙、锰、铁、铜含量偏高,而含氯量偏低。烤烟施肥应减氮减磷稳钾,普遍施硼,因土施镁。在土壤pH<5.5时,应适施石灰,调节酸度。有机无机相结合,适当改变氮肥形态防治土壤进一步酸化。实施科学施肥确保植烟土壤可持续利用。 

Soil fertility status and evolution trend under long-term flue-cured tobacco cultivation in Dali prefecture of Yunnan

Soil survey was conducted in flue\|cured tobacco production area in Dali prefecture of Yunnan province. 506 surface layer soil samples were taken representing 85% of total tobacco production land for soil fertility quality assessments. Data from this survey was compared with that from the second national soil survey done in 1983. Results indicated that soil fertility quality has been changed significantly under long term flue\|cured tobacco production. Soil organic matter content was C 27.7g/kg in average and there was a trend of decrease.For example, there were about 56.8% in 1983 but only 36.0% in 1999 of total soil samples with soil organic matter content of C >30g/kg. Average soil pH was 6.47,it also showed a trend of acidification. Soil available P was in a trend of increase.It was 27.2mg/kg P\-2O\-5 in average in some old tobacco production area and was too high to produce quality tobacco leaf. Soil available K was K\-2O 189.2mg/kg in average and there was a trend of increase as well. However, available Mg, B, Mo and Cl those secondary and trace nutrients were in the trend of deficient. The main driven forces leading to the soil fertility quality degradation in this area were unbalanced organic and inorganic fertilization, unbalanced macro\| and micro\|nutrients input. Long term over use of inorganic compand fertilizer and less or none organic fertilizers resulted in soil organic matter depletion and soil buffer capacity reduction. Large amount of ammonium N input and leaching of cations promoted soil acidification. N,P and K accumulation may induce the relative deficient of secondary and micro\|nutrients. Practical counter measures for improvement of these degraded tobacco soils were recommended.