Management of soil physical health and carbon dynamics in maize cultivated field through organic amendments

Pakistan is situated in the most intensively colonized zone of the world. With the passage of time, farmer land holdings are decreasing due to the increasing population. To feed this increasing population the available lands had been cultivated intensively even using brackish water. The use of brackish water for this intensified cultivation is the chief cause of soil particle disintegration resulting in a poor structure. To address this problem a series of experiments were conducted using organic amendments [Farm Manure (FM), Poultry Manure (PM) and Molasses (MO)] maintaining soil water level at 75% of available water contents (AWC). The recommended dosage of mineral fertilizers was applied and maize hybrid Shahanshah was used as a test crop. Addition of farm manure as treatment resulted in better water-stable aggregation (40.68 and 39.91%), soil total organic carbon (12.64 and 12.09 g kg^-1), saturated field hydraulic conductivity (27.85 and 27.04 mm h^-1), infiltration rate (26.07 and 25.38 mm h^-1), total porosity (0.49 and 0.48 m³ m^-3). Similarly, plant agronomic parameters i.e. grain yield (9.47 and 9.21 Mg ha^-1) and water use efficiency (11.13 and 10.83 kg mm^-1 yr^-1) were calculated highest in farm manure treatment plots that were significantly greater than control but were found statistically at par with other treatments. It was concluded that organic matter addition yields better soil structure that results in proper aeration, water retention, root penetration ultimately achieving yield goals along with saving up to 25% irrigation water as indicated from the correlation analysis.