Olive Husk Compost Improves the Quality of Intensively Cultivated Agricultural Soils

Abstract

Abstract Organic amendments improve the quality of degraded cultivated agricultural soils. In this work, we examined the impact of an olive husk compost (OHC) on quality‐related physical, chemical and biochemical properties of intensively managed greenhouse soil. To this end, a completely randomized block experiment involving a single factor and two treatments (viz., annual application of OHC at 30 Mg ha −1 or no application) with three replications was used for 5 years. The effect of the compost was studied at two soil depths (0–10 and 10–25 cm) and two positions relative to crop rows (viz., on rows and between rows). Application of OHC increased soil organic matter (SOM) content, which is consistent with the low degradation rate of the compost in soil and confirms its usefulness as a source of organic C for soil. Increased SOM content resulted in decreased bulk density, and also in increased porosity and available water in the soil. The amendment was also an effective source of nutrients, particularly N, P, K and Ca, the last of which contributed to decrease exchangeable Na levels in the soil surface layer. The compost increased the activity of all enzymes studied except urease. This result can be ascribed to increased microbial activity, the presence of enzymes in the compost and their stabilization by organic matter and clay in the soil. Dehydrogenase and phosphatase were the individual enzyme activities in the soil, which were correlated with the largest number of soil properties favourably affected by OHC. Copyright © 2015 John Wiley & Sons, Ltd.