Effect of sowing date and potassium fertilization on growth, yield and chemical composition of Foeniculum vulgare mill plants

Two field experiments were carried out during the seasons of 2003/2004 and 2004/2005 at the Experimental Farm of Fac. of Agriculture at Moshtohor, Benha Univ. to investigate the effect of four sowing dates (15/10, 30/10, 15/ 11 and 30/11), four treatments of K oxide (control, two sprays, three sprays and four sprays) and their interaction on the growth, yield and chemical composition of Foeniculum vulgare Mill plants. A split plot design with three replicates for each treatment was used and each replicate contained 30 plant (15 hill). The main plots were devoted to the four sowing dates and the sub plots were devoted at random to the foliar spraying with 1.5 % of potassium oxide. Plant growth parameters such as plant height, fresh and dry weights of leaves and branches as well as fruit yield/plant and per feddan were recorded and fruit quality was estimated by measuring volatile oil % and its main components. Leaves were chemically analyzed to determine N.P.K. and total carbohydrates percentage. The results obtained showed that the sowing date at 30/11 gave the tallest plants, heaviest fresh and dry weights of leaves and branches as well as increased fruit yield per plant and per feddan and oil percentage compared with all the other treatments for sowing dates, also increased total carbohydrates, N,P and K % in plant leaves compared with the different sowing date treatments. Potassium fertilization at the high rate (four sprays during growth season) increased plant growth, fruit yield and chemical composition as compared with the lower rate. The interaction between late sowing date (30/11) with the high level of K fertilizer gave the best results of plant growth, fruit yield and chemical composition compared with all the other treatments. The G.L.C. determination revealed the presence of each of L-limonene, anethole, a-pinene and chavicol compounds in the volatile oil of fruits. Fourth sowing date (30/11) plus fou r sprays of K at rate 1.5% attained 0.22, 12.25, 0.02 and 87.51% of a-pinene, L-litnonene, chavicol and anethole compounds in the volatile oil respectively.