The herb and essential oil yields parameters were
recorded at the time of harvest. The essential oil content
in the fresh herbage was estimated by hydrodistillation
method using Clevenger’s apparatus. The quality of essential
oil was determined by GLC using a 2 m 3 mm
stainless steel column packed with 10% FFAP on 80/100
chromosorb WHP. Hydrogen was used as carrier at 30
ml/min. Oven temperature was programmed from 100 to
200 C. Compounds were identified by the technique
of coinjection followed by retention time of standards
obtained from M/s S.H. Kelkar & Co. Ltd., Mumbai,
India. The nitrogen content in the plant samples was
estimated by the micro-kjeldhal method (Jackson, 1973).
Uptake of N was computed using the dry matter yield
and its N content. Apparent recovery of N was
calculated as equal to uptake of N from treated
plots uptake of N from control plots 100/amount of
fertilizer N applied. After carrying out Bartlett’s test
for homogeneity of variance, the two years data were
pooled and statistically analysed for herb and essential
oil yields (Panse and Sukhatme, 1978).