Effects of some organic materials on bicarbonate extractable phosphate content of soils having different pH

This study was carried out to determine the effects of rice husk compost (RC), town waste compost (TW) and tobacco waste (TB) on bicarbonate extractable phosphate content (P) in soils having different pH levels under greenhouse conditions. Soil samples used in this study were taken from surfaces (0-20 cm) of agricultural fields around Samsun, Northern Anatolia. The experiment was conducted according to split plot design with four doses of organic matterials (0, 2.5, 5.0 and 7.5, %). After a month of mixing organic matterials into soils, lettuce were grown in the medias. According to the results, RC, TW and TB applications into acidic (Tepecik), neutral (Kampüs) and alkaline (Çetinkaya) soils increased extractable P content. It was observed that effectiveness of organic matterials changed depend on soil reaction, type and dose of organic matterials. All organic wastes were more effective on increment of bicarbonate extractable phosphate content in neutral soil pH when compared the other soil pH levels.