Biostimulants as a Response to the Negative Impact of Agricultural Chemicals on Vegetation Indices and Yield of Common Buckwheat (Fagopyrum esculentum Moench)

Abstract

Weed control during common buckwheat cultivation is hindered by the crop’s high sensitivity to agrochemicals. This study evaluates whether biostimulants (Asahi SL, Kelpak SL, B-Nine) could reduce the adverse effect of abiotic stress caused by these substances on buckwheat’s vegetation indices and yield. To this end, a four-factor field experiment was performed according to the 3 4−1 Box–Behnken design on chernozem soil with silt texture at the Experimental Station of the Agricultural University of Krakow (Poland, 50°07′ N, 20°04′ E). The results showed that calcium cyanamide fertilization was effective in reducing the abundance of dicotyledonous weeds by 39% and the dry weight of weeds per unit area by 20% relative to ammonium nitrate-fertilized sites. However, the most effective method of weed control was the application of metazachlor together with clomazone. The mixture of these active substances reduced the abundance of monocotyledonous weeds, dicotyledonous weeds, and dry weight of weeds by 83%, 40.5%, and 36.4%, respectively. The use of herbicides adversely affected the leaf area index (LAI). Nitrophenol treatment of buckwheat grown on soil fertilized with calcium cyanamide resulted in increased achene yield and number of seeds per plant compared to ammonium nitrate fertilization. The application of daminozide on chemically protected plants resulted in improved vegetation indices such as normalized difference vegetation index (NDVI) and soil plant analysis development (SPAD) compared to sites not exposed to herbicides.