Abstract
A field experiment in a pineapple plantation at Lampung Province of Indonesia was conducted for 15 months to investigate the effect of rice husk and tapioca wastes (cassava bagasse and cassava peel) used as organic amendments, on soil physical and biological properties. The treatments included control, rice husk mulch, cassava bagasse mulch, cassava peel mulch, cassava peel-soil mixture and black polyethylene film mulch. The organic materials were applied manually at a rate of 30 kg m-2. The soil physical and biological properties at the initial and final stages of the experiment were measured and compared. The results showed that the moderate rate of rice husk’s decomposition process slightly increased SOM of surface layer that may had led to somewhat decreased particle density and available water content enhancement. On the other hand, cassava bagasse mulch decomposed within very short period after application and thus its roles especially in soil physical properties were no more noticeable in 15 months after its application. Due to the slow decomposition rate,15 months was probably too short for cassava peel to contribute in SOM enhancement as well as other soil physical properties. However, the application of investigated organic materials for soil amendment resulted in the more abundance earthworm populations, bulk density decreasing, and the increases of macro pores and WSA in general. The existence of earthworms in the soil is certainly contributed positive effects in the soil properties, especially physical soil properties. But which soil properties that were most affected by the earthworm activities cannot be concluded, since other factors such as soil microorganisms could also play a role in promoting soil properties enhancement.
