But Peruvian guano is especially rich because coastal Peru has a really dry climate.

但秘鲁的鸟粪特别丰富， 因为秘鲁沿海地区气候非常干燥。

But what was so special about Peruvian guano that made it different from the other things they’d tried?

但是，秘鲁鸟粪有何特别之处使其与他们尝试过的其他东西不同？