Biodynamic preparation 501 must be applied at least once per crop cycle to all harvested Biodynamic-certified crops. 501 is the horn silica, consisting of ground quartz or other minerals of high silicon dioxide content, mixed with water and placed in a cow horn and buried in the soil from spring to fall, afterward retrieved and stored in a sunny location. The resulting preparation is stirred in water and sprayed in the early morning hours as a fine mist over plant foliage.
In September of 2024, a Literature Review titled “Silicon, An Emergent Strategy to Lighten the Effects of (A) Biotic Stresses on Crops” was published in the Journal of Agronomy and Crop Science. This study examined plant response to the application of Silicon (Si) demonstrated in recent published studies. Some of the paper’s conclusions, grouped by category, are shown below.
Leaves
+ Improvement to leaf structure
+ Increase of transpiration rate
+ Increase of photosynthetic rates
+ Improvement of water use efficiency
+ Increase in soluble sugars
Root and Soil
+ Improvement in physical and chemical properties of soil
+ Increase in water and nutrient uptake
+ Increase in root mass and density
Biotic and Abiotic Stress
+ Protection against biotic and abiotic stresses increased
+ Increase of defenses against pests and diseases
+ Decrease in heavy metal toxicity
+ Increase in drought tolerance
+ Decrease in salinity stress
Plant Performance
+ Improved germination
+ Improved water use efficiency
+ Improved antioxidant activity
+ Increased total antioxidant capacity and total phenols
+ Increased yields
+ Increased Si concentration
+ Decreased incidence of powdery mildew and brown rot