We used to grow the same crops even before acquiring a bio-digester. By comparison, I can say without a shadow of doubt that their yields have improved given that the soil fertility that has also been improved by bio-slurry. The thickness of crops like maize is totally different from what we were used to and their colour is deep green. Plants take longer to wilt in dry conditions compared to those grown without bio-slurry. This is evidence enough that soil with bio-slurry retains more moisture than that without.
