水稻品种和砷污染对土壤溶解性有机碳氮的影响

EFFECTS OF RICE CULTIVARS AND ARSENIC POLLUTION ON SOIL DISSOLVED ORGANIC CARBON AND NITROGEN

选取有机质含量和pH不同的2种水稻土(黄泥田和红泥田),通过盆栽实验研究砷(As)污染条件下,种植9个水稻品种对土壤溶解性有机碳(DOC)和溶解性有机氮(DON)含量的影响,分析水稻品种、As污染和土壤类型的相对影响与交互作用。结果表明,水稻品种显著影响了土壤DOC和DON的变化,在水稻收获后,DOC平均含量的大小顺序为杂交稻(41.09±0.92 mg kg-1)>籼稻(38.10±1.53 mg kg-1)>粳稻(37.74±1.37 mg kg-1);DON平均含量的大小顺序为粳稻(2.94±0.40 mg kg-1)>杂交稻(2.61±0.42 mg kg-1)>籼稻(1.45±0.17 mg kg-1)。As污染降低了土壤DOC和DON的含量,但不同品种水稻的响应不同。与对照相比,As污染条件下,黄泥田和红泥田中DOC平均含量分别下降了14.4%和11.1%,DON平均含量分别下降了65.0%和44.7%;DOC在种植杂交稻后降幅最小,而DON在种植籼稻后降幅最小。在两种水稻土中,黄泥田的DOC和DON平均含量高于红泥田,在没有As污染条件下,分别高22.4%和45.8%,这与黄泥田有机质含量和pH高有关。水稻品种、As污染和土壤类型对DOC和DON变化的影响不同,3个因子对DOC变化的相对贡献率分别为7.7%、15.5%和27.6%,对DON变化的相对贡献率分别为14.7%、24.2%和2.0%。

A pot experiment was carried out using two types of paddy soils （yellow and red paddy soil） different in soil organic matter and pH, and 9 rice cultivars （three hybrid, three indica and three japonica） for exploration of effects of rice eultivars and arsenic （As） pollution on contents of DOC （dissolved organic carbon） and DON （dissolved organic nitrogen） in the soils and interactions among the three factors, rice cultivar, As pollution and soil type. Results show that rice cuhivars displayed a significant impact on content of DOC and DON in the soils, and followed a decreasing order of hybrid rice （41.09 ±0.92 mg kg 1） 〉 indica rice （38. 10 ± 1.53 mg kg-1） 〉japonica rice （37.74 ± 1.37 mg kg-1） in terms of DOC, and of japonica rice （2.94±0.40 mg kg-1） 〉 hybrid rice （2.61 ±0.42 mg kg-1） 〉 indica rice （ 1.45 ± 0. 17 mg kg-1 ） in terms of DON. As pollution decreased DOC and DON contents in the soils, but the effect varied with the rice cultivar. Compared with CK, As pollution decreased DOC by 14.4% and 11.1% and DON by 65.0% and 44.7% , in yellow and red paddy soils, respectively, and the least decline of DOC was in soils cultivated with hybrid rice, while that of DON was in the soils cultivated with indica rice. The average contents of DOC and DON were 22.4% and 45.8% higher, respectively, in the yellow paddy soils than in the red paddy soils without As pollution, which was attributed mainly to the higher organic matter content and pH in the yellow paddy soils. Rice species, As pollution and soil type differed in their effects on soil DOC and DON, and was responsible for 7.7% , 15.5% , and 27.6% of the variation of DOC, while 14.7% , 24.2% , and 2.0% of DON, respectively.