Soil Microbial Diversity and Activity Value Test

KIWITA
Jan 15
3 min read

Updated: Jan 18

About the Soil Microbial Diversity and Activity Value Test

In the past, it was believed that good soil that does not develop soil-borne diseases contained many special and highly effective microorganisms. However, investigations conducted by national and prefectural research institutions have revealed that good soil does not necessarily contain special microorganisms, but rather that a wide diversity of microorganisms is present and highly active.

Based on this understanding, research was conducted to evaluate the diversity and activity of microorganisms in soil, leading to the development of the “Soil Microbial Diversity and Activity Value.”This index quantifies how vigorously soil microorganisms decompose various organic substances, providing an objective and scientific method for evaluating the biological quality of soil.

Test Samples

Commercial potting soil and planters were used to cultivate Japanese radish sprouts (hatsuka-daikon), and the soil after cultivation was tested.
During cultivation, irrigation water sprayed onto each planter was supplemented with water-soluble silica ultra-concentrated solution (for agriculture and livestock use).
Four irrigation conditions were used:
- Tap water only
- 1,000× dilution
- 3,000× dilution
- 5,000× dilution

Test Results

Sample	Soil Treatment	Soil Microbial Diversity & Activity Value	Deviation Value
Soil A	Tap water only (No silica added)	959,225	54.9
Soil B	Silica solution (1,000× dilution)	914,201	53.6
Soil C	Silica solution (3,000× dilution)	1,146,263	60.0
Soil D	Silica solution (5,000× dilution)	978,054	55.4

Based on accumulated data held by the testing organization, the above values are generally interpreted as follows:

700,000–1,000,000: Soil management is relatively successful
1,000,000–1,300,000: Rich soil; crops are flavorful and less prone to disease

Note:The deviation value indicates how far a given value deviates from the average (50) within the population.

Discussion

From the results above, the soil treated with the 3,000× dilution exceeded a value of 1,000,000, indicating that good soil development had been achieved.The 1,000× dilution showed the lowest value, suggesting that this concentration may be slightly too strong. Based on these results, we consider 3,000× to 5,000× dilution to be the recommended guideline range.However, the optimal dilution may vary depending on soil condition, soil type, crop, and region. When using the water-soluble silica ultra-concentrated solution (for agriculture and livestock use), please apply it at an appropriate dilution rate.

Soil A: Tap Water Only