Response of Black Nightshade to Different Cropping Systems and the Effect on Physiological Parameters and Mineral Composition

Abstract

In southern African countries, production of indigenous leafy vegetables is commonly practiced at home garden and/or commercial level due to their significant contribution toward eradication of hunger, food insecurity, and malnutrition. Black nightshade (Solanum nigrum L.) is among African leafy vegetable (ALV) highly recognised for its pharmacological and nutritive benefits. Several research have shown that ALVs can be cultivated in the open field or greenhouses, however, little information is available on the changes of the agronomical parameters and mineral composition. The aim of the study was to compare the physiological parameters and mineral composition of nightshade grown in the open field vs. greenhouse cropping systems. The results of the study revealed high-leaf area and relative chlorophyll content in the open field conditions while plant height and the number of leaves were reportedly higher under the greenhouse system. Minerals elements such as magnesium, copper, manganese, iron, zinc, and aluminium were significantly higher in the open field cropping system, while greenhouse cultivation recorded higher sulphur and boron. Notably, no significant amount was observed in calcium, phosphorus, potassium, and sodium between open field and greenhouse system. Furthermore, a significant amount of total nitrogen was reported in the open field, however, no significant difference was observed in moisture and ash content for both cropping systems. In conclusion, black nightshade cultivated in open field provided higher leaf chlorophyll, leaf area, and trace elements compared to greenhouse cultivation while macro minerals concentration had no significant difference in both cropping systems.