Effect of different rates of nitrogen fertilizer on the growth and yield of Zucchini (Cucurbita pepo cv. Diamant L.) hybrid F1 in Rwandan high altitude zone

Abstract

Zucchini (Cucurbita pepo L.) is a newly introduced crop and is increasingly becoming an economically important vegetable crop in Rwanda despite of its low production due to insufficient or no fertilizer application. In view of this, a field research was conducted at Higher Institute of Agriculture and Animal Husbandry, Northern Province, Rwanda with the aim of determining the optimum nitrogen rate (Urea 46%) that could maximise Zucchini productivity. Two separate trials in a Randomized Complete Block Design with five treatments (0, 40, 80, 120 and 160 kg Nha -1 ) replicated four times were set up from September to November in 2011 and 2012. The parameters assessed were vegetative characteristics, yield and soil characteristics. The growth and yield was significantly (P � 0.05) affected by nitrogen nutrition. Plants subjected to 160 kg Nha -1 exhibited increase of about 22.9 - 55.9% in plant height; 28.0 - 29.4% in stem diameter; 26.6 - 39.7% number of leaves; 61.0 - 204.1% leaf area and 103.2 - 235.2% leaf are index compared to the control. Male and female flowers from plants subjected to 120 kg Nha -1 were more by between 13.9 - 30.8% and 7.5 - 63.5% respectively in contrast to the control. Biomass yield from 120 and 160 kg Nha -1 was about 99% higher than the control and about 15.9 tha -1 . Maximum edible fruit yield was realised from plants subjected to 120 kg Nha -1 which averaged at 11.3 tha -1 and 86.0% higher than the control and