The Chemical Composition of Turnip as Influenced by Some Pre-Emergence Herbicides

The influence of five pre-emergence herbicides, viz. nitrofen (2, 4-dich-lorophenyl-p-nitrodiphenyl ether), alachlor [2-chloro-2’, 6’-diethyl-N-(methoxy methyl) acetanilide], simazine (2-chloro-4, 6-bis (ethylaraine)-S-triazine], diuron [3-(3, 4-dichloro-phenyl)-l, 1-dimethylurea] and linuron [3-(3, 4-dichiorophenyl)-l-methoxy-l-methyl-l-methylurea] was studied on the chemical composition of turnip (Brassica rapa L.). When compared with the hand-weeded control herbicides did not show significant influence on percent dry weight and ash contents. Fat content was lowered by alachlor at 2.0 kg/ha and diuron at 0.25 and 0.37 kg/ha. Alachlor at 2.0 kg/ha, nitrofen at 1.87 kg/ha, diuron at 0.25 kg/ha and linuron at 0.25 kg/ha increased the percent protein content as compared with the weeded control. Except linuron all the herbicides caused an increase in both reducing and total water soluble sugars. The roots from the unweeded control showed significantly higher percentage of crude protein and sugars but a lower percentage of crude fibre than the weeded control.