休耕水稻田蓄水对土壤肥力影响试验

主要探讨水稻田休耕期间蓄水对休耕后土壤肥力之影响。选择两块水稻田区,在水稻收割后,将田区翻耕一次。一田区以人工连续灌溉,蓄存水量于田区;另一田区则为天然蓄水。在每一田区四边及中央处,以10cm为一层采取土样,取至60cm。再将每一层土样气干后,通过0.42mm筛网土样混合,分析田区同一层在不同时段与不同深度下之pH值、电导度值、有机质、全氮、有效磷、钙离子、镁离子、钾离子及钠离子之变化。试验结果显示:休耕后水稻根系腐化,造成土壤有机质以及有效磷显著的增加。蓄水后天然蓄水田区有机质和有效磷分别增加51%及88%,连续蓄水田区分别增加13%和69%。而天然蓄水田区镁、钾、钠分别降低35%、24%和47%,连续蓄水田区分别降低29%、14%及41%。     

WHITHER CHINA'S MARKET ECONOMY? THE CASE OF LIJIN ZHEN

ABSTRACT. Soon after Deng Xiaoping became China's premier in 1978, a program of reform and openness was initiated. Its goals were to introduce free-market mechanisms into the command economy, to eliminate Mao-era inefficiencies, and to bring China to parity with developed countries of the West and to a leadership role among Asia's newly industrialized countries. Drastic changes quickly transformed China's planned economy into one of mixed-market socialism. Although the economic achievements have been impressive and commendable at the national and provincial levels, questions have been raised as to the role of economic reform and openness in the growth and development of Chinese cities. To answer them, we examine Lijin Zhen, the seat of Lijin County, Shandong Province.