101 Questions answered
Dry Sowing Challenges: Why Repellent Sands Delay Crop Establishment
We don’t know the full answer, but the theory is that mixing repellent soil when it is dry destroys any existing pathways for water to enter, so the soil wets up very slowly and non-uniformly, causing delayed and staggered germination.
Knife points can also contribute to this, because of how the soil moves when it is dry. Repellent soil is dry and sandy, so it flows or moves easily when disturbed. When the knife points run through the soil, it funnels the dry repellent soil into the furrow, putting more repellent soil around the seed, further impeding water supply in the seed zone.
