Integrated nutrient management in spring maize production in Nepal

The source of fertilizer significantly affects phenology and yield parameters of maize (Zea mays). A field experiment at Parbat, Nepal, investigated how organic, mineral, and integrated fertilizers affect spring maize (variety: Arun-2) phenology and yield during 2018–2019. The study employed a randomized complete block design with eight treatments and four replications including poultry manure (T1), farmyard manure (FYM) (T2), chemical fertilizer (synthetic inorganic chemicals that conventional growers use) (T3), vermicompost (T4), poultry manure + chemical fertilizer (T5), FYM + chemical fertilizer (T6), vermicompost + chemical fertilizer (T7), and a combination of poultry manure + FYM + vermicompost + chemical fertilizer (T8). Results showed that T8 had the shortest period to tasseling (75 days), while T5 had the longest (82.3 days). For physiological maturity, T3 recorded the shortest duration (117.6 days), whereas T5 had the longest (124.6 days). These differences were statistically significant (p < 0.05). T5 recorded the highest cob length (15.5 cm) and biological yield (6.9 tonne ha⁻¹), whereas T2 had the lowest (10.7 cm and 3.6 tonne ha⁻¹), also showing a significant effect. T4 had the highest grains per row (25.9), while T2 had the lowest (16.5) and the most sterile cobs per plot (16.7). T6 had the fewest sterile cobs (3.7). T8 produced the highest grain yield (3.1 tonne ha⁻¹), while T2 had the lowest (1 tonne ha⁻¹), with yield differences confirmed as significant. A combination of these results suggests that integrating organic and mineral fertilizers enhances maize maturity and grain yield, while using FYM alone reduces yield.