Finance Minister Chalongphob Sussangkarn said recently that Thailand's benchmark interest rate must be cut from 4.5 percent to encourage consumer spending and spur the slowing economy.   He also said Thailand needs "counter cyclical'' policies to jump-start the slowing economy. Chalongphob added that the recent reversal of many of the former prime minister's populist policies that showered cash on rural areas had caused "too much of a shock'' and stalled consumption, hurting businesses and the population.  "One of the main agendas is to inject more money into grass roots, but try to develop a system that will make it more prudent,'' he said. "Of course you cannot wait until everything is 100 percent prudent until you inject the money, otherwise people will be dead.''