Short-term effects of hazelnut husk compost and organic amendment applications on clay loam soil
The experiment was carried on a clay loam soil to examine the short-term effects of hazelnut husk compost (HHC) and organic amendments on selected soil physical properties between 2001 and 2003. The amendments were only applied in 2001. The experimental design was replicated five times as a randomized complete block with four organic amendments: HHC, peat, farmyard manure (FM), chicken manure (CM) and soil (control). Amendments were applied at rates of 0, 12.5, 25, 50, 75 and 100 tons ha-1 (dry weight) replicated. The effect on the soil's physical properties such as bulk density, water retention characteristics, pore ratio, structural stability, and soil organic carbon were determined. All amendments and their rates had a positive effect on the physical properties of the soil. HHC decreased the bulk density of soil. The effect depended on year since application. Moreover, HHC increased soil total porosity, the amount of water held at field capacity and wilting point of soil. The 75 ton ha-1 application was most effective. Its effects on these soil properties were more obvious at the end of the second year. HHC did not affect macropore/micropore ratio of the soil until the third year, due to an increase in micropore number. Although the effects of the other organic amendments on structural stability of soil were more obvious in the second year, the effect of HHC increased in the third year, due to its high C/N ratio. The 75 ton ha-1 application of HHC increased the structural stability of the soil the most. HHC had the highest organic carbon content. The effects of HHC on physical productivity of soil generally were clearer at the end of the second year. For this reason, it is recommended that HHC should be reapplied after two years as organic fertilizer. Further studies should be carried out to determine the long-term effects of HHC on physical productivity of soils.