Thriving in a Changing Country : Performing: Singer Alan Jackson, who will appear tonight at Pacific Amphitheatre, concedes that career longevity in his field is no longer the sure thing it once was.

After Alan Jackson picked up two Academy of Country Music awards a few months ago--including at least one that everyone had conceded to Garth Brooks--he and Brooks ran into each other backstage at the Universal Amphitheatre, where they exchanged a few quiet words.

“The award that was most surprising to everybody, including myself, was the album of the year,” Jackson recalled this week. “His album (‘Ropin’ the Wind’) had sold a lot of records, and I think he was surprised not to win that. That’s what we were talking about backstage. ‘That’s the one I really wanted’ is what he said to me. I said, ‘Well I’m glad to have it too.’ ”

His excitement over the trophy he got for his “Don’t Rock the Jukebox” album, and another for the title single, goes beyond personal satisfaction. The current boom in country music’s popularity has increased the competition significantly: With new acts being signed at a fierce pace and established veterans suddenly put out to pasture, the conventional wisdom that once you’re established in the country market you’re secure forever no longer applies.

“I think as far as the fans go they’re still real loyal,” said Jackson, who headlines the Pacific Amphitheatre tonight and has his third album, “A Lot About Livin’ (and a Little ‘Bout Love”), scheduled for an Oct. 9 release.

“But I think the hardest part is gonna be with radio and the industry itself, keeping the fire going with them. Just because you had a hit last week, don’t think they’re gonna look at what you got out this week.”

Even a relative innocent such as Jackson--a 33-year-old Georgia native who prides himself on being “an average guy”--has felt the pressure.

“I think a year ago it was probably worse than now. I feel like I’ve kind of leveled off a bit. . . . It’s rolling a little easier now than it was a year ago as far as the pressure of keeping it going.

“A year ago I was at that point where I’d had a couple of hits and an album that was sellin’ real good, but I had another album coming out and didn’t know if it was gonna keep it goin’. Luckily it did.

“I think that was probably a harder time, because I’ve seen a lot of people come and go in this business real fast, and I think maintaining nowadays with all the competition’s going to be the toughest challenge. . . . The way country music is changing and growing, it’s a constant challenge to be creative or come up with the great songs.”

One increasingly prevalent way to meet that challenge is to write your own rather than rely on Nashville’s song factories.

Though Jackson says that he listens to everything that’s pitched to him by outside writers, he--along with such performers as Brooks, Vince Gill, Clint Black and Mary-Chapin Carpenter--is part of a significant movement in country music toward singers who also write their songs.

Well, some people feel it’s significant.

“I think it’s just a coincidence that it’s kind of hitting right now, I guess because there’s been so many new acts,” says Jackson, whose current No. 2 country single “Love’s Got a Hold on You” is his first hit that doesn’t bear his co-writing credit.

“I think it’s good that people are concentrating more on the songwriting. Country music was sort of in a slump a few years ago . . . because the songs may not have been the quality they should have been. And I think nowadays people are concentrating more on the songs and not just the artists. Radio is the same way. Finally radio is playing the best record, the best song, not so much some record just because some established artist’s name is on there.”

Alan Jackson and Diamond Rio play tonight at 7:30 at the Pacific Amphitheatre, 100 Fair Drive, Costa Mesa. $28.50. (714) 740-2000 (Ticketmaster).