Adding organic matter to soil proved an efficient strategy for restoring soil fertility and improving crop dry matter – an indicator of yield potential. In this regard, evaluating the sources of organic matter (OM) (control, poultry manure [PM], farmyard manure [FYM], compost, and mungbean residues [MR]) to provide 120 kg N ha^-1 and effective microbes (EM) (0, 100, 200, and 300 L ton^-1 of OM) as 2% solution proceeded in field conditions during 2017–2019. The sowing of wheat seeds (cv. Pirsabak 2015) at 120 kg ha^-1 took place in the field using RCB design with four replications. Results showed that PM/FYM had delayed the phenology and improved the biomass-related parameters, dry matter (DM) accumulation, and crop growth rate (CGR) more than compost and MR. However, the results were more pronounced when applied with 300 L EM ton^-1 of OM from the PM. The maximum DM (55%) accumulation in plant parts occurred beyond 100 days after sowing (DAS). A marked increase in DM and CGR beyond 60 DAS and a reduction in CGR beyond 120 DAS appeared irrespective of treatments. In the case of EM, the 300 L ton^-1 revealed superior in terms of growth, DM accumulation, CGR, and delayed phenology. Structural equation modeling suggested that DM production gained a direct effect from crop phenology (46.1%) and crop stand (30.4%) but no indirect effect from crop growth (24.8%). In conclusion, the 300 L EM ton^-1 of OM applied to PM or FYM had improved the crop stand, development, and DM production in wheat.

Keywords: Wheat, structural equation model, poultry/farmyard manure, compost, mungbean residues, effective microbes, crop growth

Key findings: Phenology was delayed using PM and FYM, thereby increasing the plant growth and dry matter accumulation over compost and MR. Improved DM and CGR resulted from PM, FYM, and MR with higher levels of 300 L ton^-1 of OM versus compost with a lower level of EM (100 L ton^-1 of OM). More than 50% of dry matter accumulation occurs after spikes emergence. DM production was directly affected by crop phenology (46.1%) and crop stand (30.4%) but indirectly affected by crop growth (24.8%).