The effect of supplementation of the soil-like substrate with wheat straw mineralized to different degrees on wheat productivity in closed ecosystems

Abstract

Successful incorporation of soil-like substrate (SLS) into biotechnical life support systems is often complicated by the necessity to maintain the balance between flows of mineral elements taken up from the substrate by growing plants and mineral elements added to the SLS as components of mineralized plant inedible biomass. An imbalance between these two flows can be caused by the addition of recalcitrant plant waste such as wheat straw. The purpose of this study was to determine whether the availability of essential nutrients to be taken up by the roots of the wheat plants grown on the SLS could be enhanced by supplementing the SLS with the products derived from wheat straw subjected to different levels of physicochemical mineralization in the aqueous solution of hydrogen peroxide. Different degrees of straw mineralization were achieved by using different ratios of the aqueous solution of hydrogen peroxide to straw. The study showed that supplementation of the SLS with insufficiently oxidized products of physicochemical mineralization of straw resulted in a decrease in the grain yields. The inhibitory effect of the straw subjected to physicochemical oxidation increased with a decrease in the degree to which the straw had been oxidized. Only supplementation with the straw mineralized to the highest possible degree did not inhibit plant growth and development, and the crop yield in that treatment was higher than in the other treatments.