CSX Corp. of Richmond reported a sharp drop in earnings for the first quarter, attributing the decline to further deterioration in the national economy and severe winter weather in the Midwest and Northeast.

The company reported a profit of $48.2 million ($1.16 a share) compared with earnings totaling $87.9 million ($2.14) in the first quarter of 1981.

Total revenue in the most recent quarter was $1.3 billion, a 2 percent decline from volume reported a year earlier. Transportation revenue for this year's first quarter was $1.2 billion, matching that of the comparable period a year ago.

CSX said commodity travel levels, except for the traditional seasonal increase last month, were flat during the quarter. It said general commodity carloadings were down 17 percent, compared to the first quarter of 1981.

Officials noted that in contrast to the first quarter of this year, the comparable 1981 period was a record quarter that benefited from stockpiling by utilities in anticipation of a coal miners' strike, and stronger general commodity traffic levels.

Coal traffic remained strong in this year's first quarter, although adverse weather conditions caused temporary closings of several mines and hampered dumping at export facilities during the first two months, CSX said.

Officials said they are encouraged by the current decline in diesel fuel prices which along with a firm cost control program will help hold down total railroad operating costs.

Input Business Machines Inc. of Frederick reported record sales but a steep decline in profits for the year ended Dec. 31.

For the year, net income was $65,112 (four cents a share) compared with $264,285 (20 cents) for 1980. Sales rose from $3.18 million to $3.86 million.

Four-quarter sales were up 71 percent, to $1.23 million. However, the company reported a loss of $143,922 (seven cents) in the fourth quarter last year compared to income of $5,063.