Business investment in new plants and equipment will fall by about one percent this year compared to 1981 but will be rising strongly in the second half of the year, according to a Commerce Department survey released yesterday.

A similar survey taken by the economics department of McGraw-Hill Publications Co., also released yesterday, indicated a larger 2.3 percent drop in investment.

The 500 companies responding to the McGraw-Hill survey in January and February said last year's large business tax cuts led them to raise their investment plans for 1982 by only $1 billion out of the total $345 billion they expect to spend. Corporate tax cuts, which were supposed to spur investment, will amount to nearly $10 billion this year.

The Commerce survey, which is broader than that of McGraw-Hill, indicated that businesses have revised downward their expectations for spending this year since the last survey conducted in November and December.

The deeply depressed motor vehicle industry expects to cut outlays on new plants and equipment this year by about 14 percent in real terms. Another hard-pressed industry, nonferrous metals, will cut its new investment by about 23 percent.

On the other hand, the iron and steel industry plans to increase its investment pace by about 20 percent in real terms, and the electrical machinery industry will not be far behind, with about a 14 percent gain.

Overall, the Commerce Department survey shows durable-goods manufacturers spending about 1 1/2 percent more this year than last after adjustment for inflation, while nondurable-goods makers will be cutting back by 3.1 percent.

In general terms, the Commerce Department survey is consistent with the Reagan administration's forecast of a strong economic recovery in the second half of the year. However, it also suggests that the general state of the economy and prospective markets for the goods that might be produced by new plants and machines are a much more significant factor in determining investment plans than the level of business taxes, analysts said.

The brightest news from the McGraw-Hill survey was that business anticipates a cash flow jump of 12 percent this year. "If this expectation materializes, companies should be in financial shape to increase capital outlays in 1983," McGraw-Hill said.

In a separate report, the Commerce Department said that manufacturing and wholesale and retail trade inventories fell a seasonally adjusted $2.1 billion in January compared with a revised drop of $3.4 billion in December.

During recessions, when sales fall, business executives try to bring their stocks back into line with sales by reducing orders and production of goods until they are well below current sales. Once excess inventories are worked off, production can be increased again even before sales pick up. That swing in production, which could be near, usually marks the end of the recession.