Effects of chemical and organic fertilizers on leaf area index, yield and yield components of pumpkin

To evaluate the effects of organic and chemical fertilizers on the leaf area index, yield and yield components of pumpkin, a field experiment was conducted based on RCBD with three replications during the 2010-2011 growing season at Gorgan University of Agricultural Sciences and Natural Resources, Iran. The treatments included N: (control), N1: 66-66-99 kg ha-1 NPK, N2: 132-132-198 kg ha-1 NPK, N3: 300-200-200 kg ha-1 NPK, H: 30 t ha-1 manure, HN1: (1/2 H + N1), HN2: (N2+ 1/2 H), HN3: (N3+ 1/2 H), C: 30 t ha-1 municipal compost, CN1:(1/2 C + N1), CN2: (1/2 C + N2), CN3: (1/2 C + N3) and HN: (1/2 C + 1/2 H). In this study, total dry weight, leaf area index, number of fruits per plant, number of seeds per plant, 1000-seed weight and seed yield were measured. The results showed that the application of chemical fertilizer (N3: 300-200-200 kg ha-1 NPK) decreased seed yield. The effect of manure and solid waste compost application was positive on both physiological indices and seed yield. Application of Chemical and combined fertilizers (N2: 132-132-198 kg ha-1 NPK and HN2: (N2: 132-132-198 kg ha-1 NPK + 15 t ha-1 manure) had a positive effect on all traits. The use of chemical fertilizer with FYM (HN2: (132-132-198 kg ha-1 NPK + 15 t ha-1 manure) produced the highest value of physiological indices and seed yield. In total, the results showed that the application of an NH2 treatment instead of chemical fertilizers, in addition to the considerable reduction of chemical inputs, can be a step towards achieving sustainable agriculture.