Building better "batteries..."
In the course of one of my innumerable trips to Viet Nam before the war ended, I went to the province of Chau Duc in the south of the country on the Cambodian border. It is largely inhabited by Cambodians, and I think they must be credited with the astonishing agricultural invention which I found there.
In brief, Chau Duc is approximately bisected by a long canal. I was traversing the canal with a young American army officer then serving as liaison in Chau Duc. I was completely astonished by the regular occurrence of what appeared to be dead palm trees, which furthermore seemed to have had their dead leaves reattached to their trunks. I asked what these were, and the young officer replied that they were "batteries." Still bewildered, I asked for an explanation. He told me that they were artificial refuges provided by the villagers for bat colonies, because the local farmers consider bat guano invaluable fertilizer. He further said that the villagers would fight one another if any attempt was made to establish a new "battery,"because the maximum useful number had already been established along the canal. And sure enough, as the dusk fell, we saw bats pouring out of the "batteries"and flying up and down the canal in great numbers to take the insects that also came out with the dusk.
Joseph Alsop, now retired, was a long-time columnist for the Washington Post.