Evaluating Mustard Seed Meal for Weed Suppression in Borage (Borago officinalis L.) Cultivation

A field experiment was carried out in Felin Experimental Farm (2019) in Lublin region (Poland) in order to determine the effect of white mustard (Sinapis alba L.) seed meal (MSM) on weed density as well as on borage plant growth and yield under field cultivation. MSM scattered on soil surface at rates of 2 and 3 t ha(-1). when weeds emerged and a day before emergence of borage did not affect the number of borage seedlings but caused transient growth stunting and chlorosis of cotyledons and first leaves. However, final plant height, yield of above-ground parts, mericarp dimensions and weight, content of oil in mericarps, and oil composition were not significantly affected by MSM treatment. At harvest, MSM had decomposed completely, supplying considerable amounts of phosphorus, potassium, and magnesium to the soil, but did not affect its pH or organic matter content. MSM suppressed weed density by 37%-46% during the period of highest sensivity of borage to weed competition. Among dominant weeds occurring in the experiment, Gnaphalium uliginosum and Stellaria media were the most susceptible to MSM, while Amaranthus retroflexus and Galinsoga ciliata were mildly susceptible, Echinochloa cruss-galli and Poa annua were less susceptible, and the least susceptible species was Capsella bursa-pastoris. Obtained results show that MSM may have value for early season weed suppression in borage cultivation.