The Effect of Organic Biostimulants on Beneficial Soil Microorganism Activity

Abstract

Organic biostimulants and organic fertilizers can improve soil health for various horticultural crops. The objectives of these experiments were to determine if biostimulants beneficially increase soil microorganism activity in soilless medium, and additionally measure the impact of synthetic and organic fertilizers with blackstrap molasses on plant nutrient uptake nutrient runoff. It was hypothesized that the addition of biostimulants will increase soil microbe activity. Evolution of soil carbon dioxide was measured by comparing different rates (0, 15, 30, and 45 mL/3.8 L of water) of blackstrap molasses using a randomized block design with 3 replications in nursery containers. Also, a second study using St. Augustinegrass and tomatoes fertilized with organic and synthetic fertilizers was evaluated with and without a biostimulant rate (30 mL/3.8 L of water). The plants were arranged in randomized complete block design with 6 replications. Soil biostimulants did significantly increase the microorganism activity at the 0.05 level. The highest rate of blackstrap molasses improved soil biological activity over a 4-week period. Additionally, fertilizer combined with molasses did show significant increases in soil microbiology for over 5 weeks for both tomatoes and St. Augustinegrass. Molasses increased soil microbial activity but not plant nutrition. Organic fertilizer though resulted in higher levels of phosphorus, calcium, magnesium, and sulfur in plant tissue. Further research is being conducted to measure the influence of biostimulants on the breakdown of composting plant matter. Organic fertilizer slightly increased soil water pH but reduced nutrient load pollution based on a 7-day nutrient effluent study. Total nutrients (nitrates, P, Ca, Mg, and S) runoff was significantly less than synthetic fertilizer. Organic fertilizer reduced nutrient dumping in waste effluent. Organic fertilizers can improve nutrient use efficiency.

The Effect of Molasses Application on Soil Biological Indicators and Maize Growth of Different Tillage Soil

“…Molasses application suggests a positive effect on the soil enzymes activity inducing nutrient and carbon cycling in this study; however, the sole application of molasses was not yet able to contribute sufficient nutrition for the plant growth. This result aligns with the result of Waguespack et al (2022), in which molasses increased soil microbial activity but not plant nutrition. Another investigation by Expósito et al (2022) suggested that increasing molasses concentration reduced the weight of dry shoots and fresh roots of tomatoes.…”

“…Many studies across the world have reported that the addition of soil organic amendment induces the soil's biological properties as well (Kotroczó et al, 2012;Koishi et al, 2020;Bartkowiak et al, 2022;Wydro et al, 2022) Among the soil organic amendments, molasses, a byproduct of the sugarcane industry containing macro and micronutrients (likes N, P, K, Ca, Mg, and Fe), has been applied in arable land to improve soil fertility (Madejón et al, 2001;Srivastava et al, 2012;Pyakurel et al, 2019;. The increase in soil microbial activity due to the molasses application was also noted by Waguespack et al (2022). Furthermore, another study by Omara et al (2022) indicated that the addition of molasses incline dehydrogenase activity.…”