Võ Thị Gương, Lê Quang TRí, Thái Trường Giang (trang 36-41)
Từ khoá: tính chất, tính chất hoá lý, môi trường đất, môi trường nước, nuôi tôm, lúa, Thới Bình, Cái Nước, Đầm Dơi, Cà Mau
Chemical properties of soil and water in shrimp ponds at Ca Mau province
Experiment was in 2002-2003 in one shrimp cultivation cycle on 2 systems of shrimp monoculture and shrimp rice system rotation. Results: bottom soil pH of shrimp ponds in potential and actual acid sulfate soils were dropped below 5 after drying. Soil salinity was increased up to 41.cm-1 at the end of shrimp cycle. Organic matter content in shrimp pond was gradually increased in potential acid sulfate soil. Labile organic N which is easily decomposed to release N available tended higher in shrimp ponds on acid sulfate soils compared to those in alluvial soils. Water quality was not different in both shrimp cultivation systems. Dissolved oxygen, pH, COD, BOD, total suspended solid, total dissolved solid were recorded in an optimum range for shrimp growth during dry season. Other factors need to be improved: salinity, alkalinity. Nitrogen and phosphorus nutrients were low led to low chlorophyll-a content, meaning of effect to natural food chain in ponds. Hydrogen sulfide was found 0.03-0.71ppm, not suitable for shrimp.