BEIJING, Feb 28 (Reuters) - Base metals mostly lost ground on Wednesday after U.S. Federal Reserve Chairman Jerome Powell's pledge to stick with gradual increases in interest rates boosted the dollar and top metal consumer China's manufacturing growth slowed more than expected. "Fed Chair Powell's testimony to the House Financial Services Committee was supportive of the USD as he indicated that the recent market swings have not changed the Fed's policy going forward," brokerage Marex Spectron wrote in a note. A stronger dollar makes metals more expensive for holders of other currencies, weighing on prices. FUNDAMENTALS: * SHFE COPPER: The most-traded April copper contract on the Shanghai Futures Exchange slipped 1.4 percent to close at 52,590 yuan ($8,311.34) a tonne, posting a 1 percent drop for the month. * LME COPPER: Three-month copper on the London Metal Exchange edged down 0.4 percent to $6,991.50 a tonne by 0712 GMT, extending Tuesday's 1.3 percent dip to slip below the $7,000 a tonne mark. * USD: The dollar stood near a three-week high against a basket of currencies on Wednesday after Fed Chairman Powell's upbeat views on the U.S. economy bolstered bets on further interest rate hikes this year. * CHINA: Growth in China's manufacturing sector in February slowed more than expected to the weakest in over 1-1/2 years as Lunar New Year holidays disrupted business activity and tougher pollution rules curtailed factory output. * OTHER METALS: Shanghai zinc, nickel and lead ended down 1 percent, 0.4 percent and 1.5 percent, respectively. Only aluminium closed in positive territory, rising 0.6 percent, although it still registered a drop of 1.9 percent for the month. * ALUMINIUM: London aluminium was also up, by 0.2 percent, "supported by LME warrant cancellations once more and the widening backwardations in the nearby spreads," Malcolm Freeman, CEO of Kingdom Futures, wrote in a note. Cancelled warrants are orders to take metal out of a warehouse. * ALUMINIUM: The U.S. Commerce Department said on Tuesday it had made a final determination that imports of aluminium foil from China are being sold in the United States at less than fair value and producers are benefiting from subsidies from Beijing.