Compost suppresses Pythium ultimum

In controlled studies, soil amended with 20% compost consistently suppressed Pythium ultimum, a soil dwelling pathogen that is part of the disease complex black root rot.  Cucumber seeds are highly susceptible to P. ultimum and were used as indicators of suppression.  Percent germination of seedlings suggests the level of suppression achieved by each treatment.  Soil […]

Compost can affect soil salinity

Two types of finished compost, manure compost and spent mushroom compost, both significantly increased soil salinity.  However, with sufficient irrigation, the spike in electrical conductivity was reduced to within optimal levels by January (1.5 months after compost incorporation) and possibly earlier.  In a field with deficit irrigation, high EC levels were still measured in soil […]

Compost buffers soil pH

In all of our field trials, compost significantly buffered soil pH .  When soil pH was low-mid 6, compost amended plots raised the pH to low-mid 7, and when the soil pH was closer to 8, it lowered it to mid-7.  Below are two examples from different fields.