The Union Pacific Corp. yesterday reported a 45 percent increase in profits during 1979 and said that for the first time in the corporation's history, more than half of its earnings came from its energy and natural resources businesses instead of its railroad.

The Union Pacific Corp.'s net income for 1979 was $382.5 million, compared with $261.1 million in 1978. Earnings per share during 1979 rose to $8.02 compared with $5.55 in 1979.

A Union Pacific spokesman in Omaha, Barry Combs, said the record earnings reflected big growth in the natural resource business rather than any decline in the railroad.

The corporation rode a 27 percent fourth-quarter profit increase to year-end records.

Each of the corporation's four subsidiaries reported record profits. Total corporation revenues were $4.03 billion in 1979, a 35 percent increase over the $2.99 billion in 1978.

Champlin Petroleum Co.'s earnings climbed to $1.82.1 million, up 91 percent from the previous year; Union Pacific Railroad's net income was $150.7 million, an increase of 8 percent; Rocky Mountain Energy's net income was $37.2 million, up 35 percent, and Upland Industries' earnings more than doubled to $18.4 million.

National Steel Corp. yesterday reported a 13 percent increase in net income in 1979 over the previous year.

The nation's fourth-largest steelmaker said it earned $126.5 million ($6.56 a share) on sales of $4.3 billion last year. In 1978, the company earned $112.4 million ($5.85 a share) on sales of $3.8 billion.

"Earnings increased for the second consecutive year despite a slow start in the first quarter resulting from severe winter weather, illegal strikes by steel haulers, and lower fourth-quarter demand from the automotive market," said National Chairman George Stinson.

Stinson said steel orders for the 1980 first quarter are below those for the same period last year because of "the recessionary climate affecting most American businesses."

However, he said bookings are strong for tin mill products, oil country goods and railroad products.

National Steel will spend about $300 million in capital expenditures this year in equal portions for modernization, environmental and maintenance programs, Stinson said.

Bausch & Lomb Inc., the optical firm, earned $3.49 a share last year, up from $2.54 in 1978 on a rise in sales to $503.03 million from $441.68 million.

Net income rose to $41.23 million from $29.85 million.

Final quarter profit was $11.7 million (98 cents a share), on sales of $132.21 million compared with $8.46 million (72 cents a share) a year earlier on sales of $122.85 million.

The company said sales of contact lens products rose 17 percent for the year and 15 percent for the quarter but profit margins narrowed.

Ophthalmic products sales were about even with those of 1978 while sales of sun glasses and other consumer products were 15 percent higher and earnings from these jumped 33 percent because of improved price margins.

Avco Corp., the conglomerate, yesterday reported an 8 percent gain in profit for 1979 on a 12 percent rise in revenues.

Net income was $132.3 million ($8.56 a share) on sales of $1.93 billion compared with $122.7 million ($8.96 a share) in 1978 on sales of $1.73 billion. cThe drop in per share profit resulted from a significant increase in the number of shares outstanding.

Fourth quarter profit was $31.3 million ($1.77 a share) on sales of $520.6 million compared with $27.7 million ($1.89 a share) a year ago on sales of $462.8 million.

Chairman James R. Kerr said Avco's finance and insurance businesses and its manufacturing operations both contributed to the gains.