Nutrient availability and pH level affect germination traits and seedling development of Conyza canadensis

Abstract

Reducing pesticide application in agricultural land is a major challenge for the twenty-first century. Responses of weed seed’s germination and seedling’s early development to chemical soil conditions around the seed may be a promising way to aid weed control in a no-till system. Thus, the objective of this work was to test, under controlled conditions, whether different chemical conditions affect the germination and development of horseweed [Conyza canadensis (L.) Cronquist]. We used, as treatment, solutions containing different nutrients (P, K, Ca, and Mg), separately and in combination, and at two pH levels (4.8 and 6.5). Phosphorus alone inhibited horseweed seed germination at ~ 7 times while had ~ 4 times reduction in final germination percentage and germination speed index for both pH tested. Other nutrients tested had a no-effect in germination speed index compared to the control treatment. Potassium alone or associated with other ions (P, Ca, and Mg) at pH 4.8 had a synergistic effect on seedling development (root and shoot length). In the same way, K associated with Mg was synergistic to the root length at pH 6.5. Seeds in the control treatment (distilled water) presented a high germination speed index at pH 6.5, while at low pH this parameter was higher when in association with KMg, PMg and Ca. The findings demonstrate that seed germination traits and seedling development of horseweed depend on nutrient kind exposure and pH conditions in the seed environment. This work suggests that adequate topsoil management (i.e., pH and nutrient availability) may aid to reduce weed germination, because, it consists of an important factor of weed occurrence in agricultural areas.

Efficacy of Agricultural and Food Wastes as the Growing Media for Sunflower and Water Spinach Microgreens Production

“…Although the 100% leaf-compost media had significantly higher N and Mg, the growth and yield of both microgreens were lower, and in the 50% leaf compost mixed with coconut coir dust (1:1 v/v of CD:LC), the significant differences of P, K, and Ca concentrations were not observed. Generally, it is well-known that nutrient exposures could lead to changes in metabolic seed mechanisms, which may involve seed-nutrient balance and physiological seed deterioration [33,34]. These mechanisms need to be explored in future studies to find each nutrient's influence on the germination process of microgreens.…”