玉米不同种植模式对坡耕地红壤团聚体的影响

Effects of different planting patterns of maize on red soil aggregates in sloping farmland

通过田间小区试验单作玉米、马铃薯//玉米间作,采集玉米在3个不同生育期(拔节期、大喇叭口期、抽雄期)的根系和土壤,测定根系分泌物中的有机酸、总糖和土壤团聚体状况,分析根系特征和根系分泌物对土壤团聚体的影响。结果表明,间作玉米根长、根体积、根表面积显著高于单作玉米(P<0.05)。玉米根系分泌总糖和总有机酸含量随生育期的推移而增加,间作显著提高玉米根系分泌总糖和总有机酸含量(P<0.05)。抽雄期,间作玉米比单作>0.25mm水稳性团聚体含量(R0.25)显著提高8.17%(P<0.05);团聚体几何平均直径(GMD)显著提高12.24%(P<0.05),分形维数(D)显著降低1.09%;团聚体破坏率(PAD)显著降低26.08%。玉米根系分泌总糖含量、总有机酸含量与R0.25、GMD、D、PAD呈极显著相关关系(P<0.01),玉米间作对改变玉米根系特征及根系分泌物中总糖和总有机酸含量、提高土壤团聚体的稳定性有很大影响。

Through the field plot test for monocropping corn, monocropping potatoes and corn intercropping potato, collection of corn in different development stages of the three (elongation stage, bell stage, tasseling stage) of root and soil, and determine the organic acid and total sugar in root exudates. And soil aggregate status, analysis of root characteristics and root exudates on soil aggregates. The results showed that the root length, root volume and root surface area of intercropping maize were significantly higher than those of monoculture maize(P<0.05). The total sugar and organic acid secreted by maize roots increased with the growth stage. Intercropping significantly increased the total sugar and organic acid secreted by maize roots (P<0.05). At tasseling stage, the water stable aggregate content(R0.25) of>0.25 mm in intercropping maize was significantly increased by 8.17% compared with that of monoculture maize(P<0.05). The geometric mean diameter(GMD) of aggregate was significantly increased by 12.24%(P<0.05), and the fractal dimension(D) was significantly decreased by 1.09%. The percentage of aggregate destruction(PAD) was significantly reduced by 26.08%. The total sugar and organic acid secreted by the root system of maize were significantly correlated with R0.25,GMD,D and PAD(P<0.01). Therefore, maize intercropping potato can change the characteristics of maize root system, increase the total sugar content and total organic acid content secreted by maize root system, and then improve the stability of soil aggregates.