Fish processing by-products utilization for soil amendment purposes

Abstract

Microbial biomass carbon and nitrogen in tested soils have been increasing along with fish bones application but not so drastically as microbial abundance. In amended agricultural soils the microbial biomass nitrogen was more than 2 times and carbon more than 3 times higher than in forest soils. Two soils differing in pH value and in the texture have been taken for the experiment settlement - medium heavy loam and sandy loam. In order to examine the possibilities of fish processing wastes to improve soil properties, the methodology was elaborated, and the experiment started. Thus, after the preparation of fish bones, their powder was obtained and when mixed with the soil, it was placed into the special vegetative pots of 5 1 in volume up to the thickness of 25 cm. The experiment has designed in 4 variants and 6 replications. The results obtained show that fish bones application has significantly influenced the increase of available phosphorus, mineral, nitrate and ammonium nitrogen content in the both experimentally tested soils. In general, the noticeable higher positive impact of fish bones application was observed in the sandy loam (forest) soil. The fish bones application have had positive effect on the content of available potassium, calcium and available sulfur in the medium heavy loam soil as well as on the content of available potassium, calcium, magnesium, total nitrogen and available sulfur in the sandy loam soil. In the case of magnesium and total nitrogen content, the increase was significant. Also, the fish bones application has decreased the acidity of sandy loam (forest) soil by 0.1-0.3 unit. Neither the amount nor the time of fish bones application did show any noticeable impact on soil pH value, magnesium and total nitrogen content in medium heavy loam soil. The organic carbon content remained unchanged both in medium heavy loam and sandy loam soils. Fish bones application has significantly influenced the increase of microbiota abundance in medium heavy loam (agricultural) as well as in sandy loam (forest) soils. However, the significantly by 2-9 times higher abundance was estimated in amended agricultural soils.