Soil structure as a significant indirect factor affecting crop yields

The use of organic amendments for improving soil properties including soil structure is crucial for sustainable soil management. In this study, two organic materials (1. compost, and 2. farmyard manure) both at a rate of 44 t ha-1 as well as their combination were applied to a Hortic Calcaric Fluvisol (Slovakia) to evaluate the soil physical properties to test the potential of these amendments for soil amelioration under gardening conditions. The results showed that the addition of organic amendments did not have any significant effects on bulk density, total porosity, soil moisture and aeration, but their application influenced the total contents of dry-sieved aggregates as well as water-stable aggregates. The highest content of dry-sieved macro-aggregates was in compost > farmyard manure + compost > farmyard manure > control (unfertilized). The stability of aggregates was higher in compost and farmyard manure + compost treatments than in farmyard manure compared to control. Also, better soil structure stability evaluated by vulnerability coefficient was in farmyard manure + compost and compost than in farmyard manure. The highest contents of soil organic carbon and humic substances were found in the farmyard manure + compost treatment and then compost > farmyard manure > control. In compost, farmyard manure and farmyard manure + compost treatments, cabbage yield increased by 52, 22 and 72%, respectively compared to control treatment. Cabbage yields linear also increased as a result of increasing of soil organic carbon and humic substances.