(.EFFECT OF SOURCE AND LEVEL OF PHOSPHORUS FERTILIZER ON YIELD AND QUALITY OF COMMON BEAN (Phaseolus vulgaris L

Abstract

Two separate field experiments on common bean (Phaseolus

vu/guris L)cv. Nebraska were carried out to study the effect ofP-level (0, 24

.32.and 40 kg P2 0s /fed.) within P-source (SP. MAP and DAP) as well as tim and frequency of P-application on grov\th. dry seed yield and its components and chemical composition of common bean plants. Experiments were carried out under field conditions offann ofthe Horticultural Services Unit, Ministry of Agriculture of Egypt at Moshtohor, Kaliobya during the two summer seasons of 1998& 1999. Experimental design \vas split-plot in the first experiment and a complete randomized block design in the second one. Results showed that:

First experiment:

Adding Phosphonts fertilizer at 32 kg P:O; /fed. as diammonium phosphate (DAP) gave higher growth, dry seed yield per plant or feddan '' ith higher NPK content of common bean plants as compared with rate supplied with superphosphate (SP) and monoammonium phosphate (MAP) '' ithin all studied levels of P-fertilizer. This treatment increased dry seed yield /feddan by 20.2 and 37.4 (% more than SPat the same level: 32kg P:ORecl . in both seasons of 1998& 1999, respectively. Second experiment:

Studies showed that adding superphosphate (SP) at 3-split applications,

50kg SP at pre- planting +100 kg SP at germination stage +50 kg SPat llO\\ering stage. gave higher plant growth. dry seed yield with better yield components and higher composition of NPK in common bean than those n.:ccived SP at one or two times with or without sulpher application at the same level of200 kg SP I feddan.