Chemical properties and sustainability of rice soil in rice-shrimp farming in Baclieu
2009
Lam Van Khanh, Ngo Ngoc Hung; Nguyen Bao Ve; Nguyen Thanh Tuong
Rice-shrimp farming is a special cultural system in seasonally saline areas. Rice-shrimp farming may give highly profitable land use practice, in turn, soil and water environment may become degraded. Rice grain yield in Bac Lieu only reached about 3-4 t ha-1 and at some years, a thousand ha of the rice area which belong to rice-shrimp system were unharvested. The surveys on soil and water have been conducted in Bac Lieu during August 2007 to June 2008 at four agro-ecosystems with existence of rice-shrimp farming, pH of canals, fields and soil surfaces were at suitable range for rice cultivation. Ece of rice fields varied with irri-gated EC.,At Phuoc Long, soil Ece was high at beginning of the rice crop (12 mS cm-1) and remained high at harvest (8 mS cm-1). These Ece values were not suitable for rice growth and therefore less suitability for rice production. The use of saline water to rise shrimp at Phuoc Long after many years has caused high soil ESP and SAR and the soil could be grouped as saline-sodic soil. There is the need to have field research related to mitigate saline-sodic situation in rice-shrimp farming.
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