Effect of NPK 16-16-16, poultry-mushroom waste compost and their combinations on growth and yield of okra

Abstract

A pot experiment was conducted to study the effects of poultry-mushroom waste compost (PMWC), NPK 16-16-16 (NPK) and their combined applications on vegetative growth and yield of okra [Abelmoschus esculentus (L.) Moench] during June-November 2014. The experiment included nine treatments: Unfertilized control (T1), NPK 2.5 g/kg (T2), NPK 5 g/kg (T3), NPK 10 g/kg (T4), NPK 2.5 g/kg+PMWC 120 g/kg (T5), NPK 5 g/kg+PMWC 120 g/kg (T6), PMWC 60 g/kg (T7), PMWC 120 g/kg (T8) and PMWC 240 g/kg (T9). Results showed that all fertilizations increased growth and yield of okra compared with no fertilization. 10 g/kg NPK (T4) greatly inhibited the growth of plant height before 30 days after sowing (DAS) and leaf growth before 15 DAS, with maximum numbers (19.17) of flowers and minimum fruit-setting rate (35.26%). 5 g/kg NPK combined with 120 g/kg PMWC (T6) advanced maximum growth rate of plant height and most greatly enhanced early flowering. T9 with 240 g/kg PMWC obtained maximum numbers (9.83) of fruits. Individual applications of NPK (T2, T3 and T4) significantly promoted more fallen leaves and higher defoliation ratio at 90 DAS over other treatments and decreased the fruit-setting rate as increasing NPK levels. Individual applications of PMWC increased plant height, leaf number and fruit number with increasing PMWC levels. As mentioned above, application of 240 g/kg PMWC is recommended in south-eastern China for its highest yield, low cost of production and maintenance of soil fertility.