Sławomir Józef Krzebietke

The proper fallowing of soil maintains or even improves its yield potential. The aim of this research was to compare five methods of soil protection with high production potential on the yield and quality of strategic plants. The tested methods consisted of five variants: bare fallow—BF; natural fallow—NF; fodder galega (Galega orientalis Lam.)—FG; a mixture of fodder galega (Galega orientalis Lam.) with smooth brome (Bromus inermis)—FG+SB; and smooth brome (Bromus inermis)—SB. The soil had been set aside for 9 years, after which time the fallows were terminated and the fields were cropped with winter oilseed rape, winter wheat, and spring wheat in three consecutive years. After the end of fallowing, the content of Nog. and Ctot., pH, and forms of available macro- and microelements in the soil were determined. The influence of each type of fallow on the yield of seeds/grain, straw, total protein, crude fat, and the content of macronutrients in the seeds/grain and straw of the grown crops was determined. Regarding the yields of the crops, the best solution was long-term soil protection via sowing fodder galega or a mixture of fodder galega and smooth brome. A field previously maintained as a fallow with these plants (singly or in combination) could produce over twice-as-high yields of wheat and oilseed rape as those harvested from a field established on bare fallow. The yields of the cereals and oilseed rape obtained in this study prove that food security and environmental protection issues can be reconciled. The methods for protecting farmland temporarily excluded from agricultural production presented in this paper correspond perfectly to the framework of the Green Deal for Europe. Arable land excluded from cultivation can be used to overcome new challenges facing modern agriculture.

The aim of this incubation experiment was to evaluate the effect of Tenebrio molitor L. frass on selected chemical and microbiological properties of acid peat. The optimal rate of mealworm frass in the substrate for growing ornamental trees and shrubs was determined. Acid peat was fertilized with frass or urea at five nitrogen (N) rates: 0, 50, 100, 200, and 400 mg dm−3. Mineral N content and electrical conductivity increased, and calcium content decreased in peat with increasing N rates. Similarly to urea, frass increased the ammonification rate at the beginning of incubation and the nitrification rate from the second week of incubation. Higher frass rates increased the abundance of plant-available nutrients (N, P, Mg, K, and Na) in acid peat. Frass undesirably decreased the counts of bacteria with antagonistic activity against soil-borne plant pathogens. Regarding the abundance of functional genes, the optimal N rate was 100 mg dm−3, which promoted the growth of N-fixing and chitinolytic bacteria. Higher N rates promoted the development of aerobic spore-forming bacteria, which produce antibiotics that can be used as biocontrol agents. Moderate fertilizer rates contributed to N accumulation in bacterial biomass. These preliminary findings, which indicate that insect frass can partially replace mineral fertilizers, are promising and can be used in pot and field experiments testing various plant species.