Effect of compost rates and time of application on growth, yield and chemical composition of snap beans, Phaseolus vulgaris L.

A field experiment was conducted at Agricultilral Experimental and Research Station, Faculty of Agriculture, Cairo University, Giza, Egypt in the two summer successive seasons 2008 and 2009. The present work aims to study the response of snap bean to different rates of compost and time of application in comparison with two different sources of inorganic fertilizers. The experiment included 8 treatments, the recommended mineral fertilizer (MF) as a control, Natural fertilizer (NF) ,i.e. 4,6 and 8 tons of compost as organic sources were applied once through soil preparation (O). These treatments were applied at two equal splits at soil preparation and 30 days after sowing (S). The same rate of (N: P: K (50:45:60) kg / fed) was applied either in MF or NF treatment. The N source in both treatments was ammonium sulfate, super phosphate (P) and potassium sulfate (K) in MF treatment and phosphate rock (P) and natural potassium (K) in NF treatment. Results showed that MF, NF, 4 tons compost O and S treatments produced significantly taller plants in combined over seasons. The highest value of plant height was obtained by the MF treatment. The lowest compost rate (4 tons /fed) S surpassed all treatments in early yield of snap beans pods. Both recommended mineral fertilizer and 4 tons splitting applications of compost significantly yielded the highest total yield. The compost treatments applied at two equal splits of the three different rates produced higher early yield and total yield in comparison with the corresponded rates added once in combined over seasons. Meanwhile, No significant differences were detected between all treatments for pod length, pod weight and number of branches per plant. The plant treated with 4t/fed organic fertilizer had the highest NPK percentage compared to 6 and 8 t/fed. The plants treated by 8 tons compost O possessed the highest values of leaves total chlorophyll. Higher values of fresh and dry weight of roots, stems and leaves were produced in the plants which received the lowest rate of compost in combined over seasons.