In the process, it also leaves behind castings that, according to the book Step by Step Organic Vegetable Gardening, are “five times as rich in nitrogen, phosphorus, and potassium [as] the surrounding soil. ”
Un, kā bija teikts kādā avotā, slieku pārstrādātā augsne ir ” piecas reizes bagātāka ar slāpekli, fosforu un kāliju nekā pārējā augsne ”. ( Step by Step Organic Vegetable Gardening.)