Organic fertilizer sources improve the yield and quality attributes of maize (Zea mays L.) hybrids by improving soil properties and nutrient uptake under drought stress

In abiotic stresses, drought is the main problem in agricultural production which inhibits the plants to show off their genetic potential. Maize is not only the cereal crop of the world but also 3rd important cereal crop in Pakistan. Maize is drought-sensitive and affected at each growth and development stage. So, the organic amendment is not only the solution to mitigate the drought stress due to long-lasting moisture availability but also improves the growth, yield, quality, and nutrient uptake with improving soil properties. Therefore, a two-year field experiment during 2018 and 2019 was laid out at Agronomy Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan. Treatments included pre-screened maize hybrids: P-1429 (drought-sensitive) and Dk-6724 (drought-tolerant); pre-optimized levels of each organic fertilizer source (OFS); recommended chemical fertilizer source (CS), 10 t/ha biochar (BC), 10 t/ha farmyard manure (F.M) and 10 t/ha poultry manure (P.M); and irrigation regimes i.e normal irrigation (Ck) 100 % field capacity and severe drought (SD) 50 % field capacity. The Experiment was designed in a randomized complete block design (RCBD) with a split-split plot arrangement and was replicated three times. Irrigation regimes were put in the main plot, organic fertilizer sources were put in the subplot and maize hybrids were put in the sub-sub plot. Different agronomic growth and yield attributes, quality attributes, crop physiology, soil physical properties, nutrient uptake, and activity of antioxidant enzymes were assessed. It resulted that in organic fertilizer sources application, 10 t/ha poultry manure and farmyard manure followed by biochar improved the growth and yield of maize hybrids significantly, under normal irrigation and severe drought. These also improve the quality of maize by improving the nutrient uptake and soil physical properties like increasing the soil porosity and decreasing the soil bulk density during consecutive years 2018 and 2019. It was also noticed that the application of organic fertilizers mitigated the adverse effect of drought by the antioxidant defense system with the production of SOD, POD and CAT.