临安市近30年农田土壤地力演变状况

临安市近30年随着种植业结构、耕作制度、施肥习惯和作物产量等变化，引起农田土壤地力演变。据20世纪80年代初期第2次土壤普查和2008—2010年耕地地力调查数据前后比较，临安市农田土壤肥力已发生了很大变化，其变化结果表明，土壤pH呈下降趋势，耕层厚度变浅，有机质、全氮含量下降，碱解氮含量基本稳定，速效磷含量呈上升趋势，土壤钾含量缺乏。为提高作物产量和改善土壤地力，农田土壤应积极推广使用秸秆还田，推广测土配方施肥技术等技术措施，是提高作物产量和改善土壤地力长期有效的途径。

A Change in Farmland Fertility in Linan City for Nearly 3 Decades

With a change in planting structure, cropping system, fertilization practice and crop yield in Lin＇ an City for nearly 3 decades, a change in farmland fertility followed. By comparing soil nutrients and some other soil properties in the farmland analyzed in the farmland fertility investigation conducted between 2008 and 2010 and the second soil census taken in the early 1980s, we found a significant change in farmland fertility in Lin＇ an City, with a result of decreased soil pH value, the thinned plough horizon, a fall in the contents of organic matter and total nitrogen, along with relatively stable contents of available nitrogen, an increasing trend in the content of available phosphorus and deficiency in available potassium. According to the analysis results above, we recommended that the practice of rice straw returned to the farmland and soil testing-based formula fertilization should be promoted as a long-term effective farming technique to increase the yield of crops and improve farmland fertility.