关键词:

淡化海砂, 无土栽培, 南海诸岛

Abstract: Peat and rock wool needed frequent replacement, so it were not suitable as substrates in soilless culture for the South China sea islands because of the higher transportation costs. Sea sand, as local materials, was easy to draw and could be used as better substrates in soilless culture. There was no studies on using desalted sea sand as culture substrates in China. In order to clarify its feasibility, this experiment took 3∶1 coconut chaff and vermiculite mixed-substrates as the CK and treated desalted sea sand(T) to cultivate lettuce, and analyzed the morphological index, yield, nutritional quality and food safety indexes of lettuce. The result showed that: ① The yield of lettuce commercial products and total dry weight cultured in T were 14.93% and 49.73% higher than the CK, respectively. ② The soluble sugar content of lettuce cultured in T was 2.47% higher than the CK（0.37%）, while the nitrate nitrogen content was 1.77 mg/g lower than the CK（12.67 mg/g）. The differences were extremely significant（P＜0.01）. The differences in soluble protein and vitamin C contents of lettuce cultured in T were not significant with that of the CK. ③ There were no obvious differences in Ca, Fe, Mg, Zn contents between lettuce cultivated in T and the CK. The As and Cd contents of lettuce cultivated in T and the CK were all accord with the national standard. These results indicated that yield of lettuce cultivated in desalted sea sand was normal. Its nutritional quality was good and food safety was OK. It was feasible to use desalted sea sand as substrates in soilless cultivation.

Key words: desalted sea sand, soilless cultivation, the south China sea islands