ABSTRACT
A field experiment was conducted with native soil; sewage sludge (SS); horse manure (HM); chicken manure (CM); vermicompost, organic fertilizer and inorganic fertilizer mixed with the native soil. The soil in each of the seven treatments was also mixed with biochar and planted with eggplant. Eggplant fruits were analyzed for vitamin C, total phenols, and soluble sugars. The number and weight of fruits obtained from inorganic treatments were not significantly different from those obtained from organic fertilizer. Concentrations of total phenols were greatest (28 µg g-1 fresh fruits) in fruits of plants grown in vermicompost mixed with biochar compared to SS and HM amendments. Vitamin C was greatest (265 µg g-1 fresh fruits) in fruits of plants grown in soil amended with biochar compared to all other amendments. Plants grown in CM amended soil were 62% and 67% greater in size compared to plants grown in SS-biochar or vermicompost-biochar amended soil, respectively.
Subject(s)
Fertilizers/analysis , Fruit/chemistry , Manure/analysis , Solanum melongena/chemistry , Animals , Ascorbic Acid/analysis , Chickens , Fruit/drug effects , Horses , Phenols/analysis , Soil/chemistry , Solanum melongena/drug effects , Sugars/analysisABSTRACT
Two plant species, arugula (Eruca sativa) and mustard (Brassica juncea) were field-grown under four soil management practices: soil mixed with municipal sewage sludge (SS), soil mixed with horse manure (HM), soil mixed with chicken manure (CM), and no-mulch bare soil (NM) to investigate the impact of soil amendments on the concentration of glucosinolates (GSLs) in their shoots. GSLs, hydrophilic plant secondary metabolites in arugula and mustard were extracted using boiling methanol and separated by adsorption on sephadex ion exchange disposable pipette tips filled with DEAE, a weak base, with a net positive charge that exchange anions such as GSLs. Quantification of GSLs was based on inactivation of arugula and mustard myrosinase and liberation of the glucose moiety from the GSLs molecule by addition of standardized myrosinase (thioglucosidase) and spectrophotometric quantification of the liberated glucose moiety. Overall, GSLs concentrations were significantly greater (1287 µg g-1 fresh shoots) in plants grown in SS compared to 929, 890, and 981 µg g-1 fresh shoots in plants grown in CM, HM, and NM soil, respectively. Results also revealed that mustard shoots contained greater concentrations of GSLs (974 µg g-1 fresh shoots) compared to arugula (651 µg g-1 fresh shoots).
