Relative Effectiveness of Phosphorus and Potassium Along with Compost and Organic Acids on Maize Crop Grown in Calcareous Soil: a Multivariate Analysis

The present study aims to enhance the morpho-phsyiological traits, effective utilization of phosphorus and potassium, nutritional quality, and maize productivity using combinations of inorganic and organic amendments in alkaline calcareous soil. The inorganic fertilizers were applied as control (PK0), recommended PK (PKR), and 75% of PKR (PKR75) either alone or in combination with different composts; university compost (UC), NIAB compost (NC) and vermicompost (VC), and organic acids; citric acid (CA) and oxalic acid (OA). The results indicated a significant effect of treatments on morpho-physiological and biochemical attributes of maize during crop growth. Stomatal conductance (gs) and transpiration rate (E) increased up to 93% and 139%, respectively, over control when PKR75 was applied with NC + CA. While, photosynthesis and chlorophyll contents were maximum at PKR75 along with UC + CA. The PKR along with UC + CA increased grain yield (108%) and biological yield (98%) over control. Moreover, the respective treatment increased P content in straw and grain up to 100% and 122% over control (P content: 0.08 and 0.18%), respectively, while 14.3 and 21.2% higher over PKR treatment (0.14 and 0.33%), respectively. The maximum K accumulation in maize grains was noted with PKR combined with NC + CA which was further confirmed with principle component analysis. The results clearly suggest integrated use of mineral PK fertilizers along with composts and organic acids could be an effective strategy to increase P and K supply, and enhance qualitative and quantitative parameters of maize grown on calcareous soil.