The Mulch Robs Nitrogen Myth
...But this happens only if you incorporate mulch into rather than on top of soil. When you top dress your soil with mulch some nitrogen at the surface will be locked up, but this actually works to your benefit by inhibiting weed seed germination. Far from reducing nitrogen, as mulch decomposes it will actually increase the nitrogen content of your soil. This is one of the many benefits of using wood chips over inorganic mulches such as gravel. I so...