我国北方风蚀区冬油菜抗风蚀效果

河西走廊地区属我国北方风蚀区,通过对河西走廊冬油菜、冬小麦、麦茬和春播等4种主要农田地表类型(处理)进行风洞模拟实验,比较各个处理的抗风蚀效果.结果表明:冬油菜、冬小麦、麦茬和春播4种处理地表的粗糙度分别为4.2、4.1、3.9和0.7;起动风速分别为14、13、12 m · s~(-1)和6 m · s~(-1);平均风蚀模数分别为22.3 、23.3、42.5 kg · hm~(-2) · h~(-1)和543.6 kg · hm~(-2) · h~(-1);输沙率分别为0.1、0.1、0.2 g · m~(-2) · min~(-1)和23.3 g · m~(-2) · min~(-1).依据粗糙度、起动风速、风蚀模数和输沙率评判,4种主要地表类型的抗风蚀效果依次为,冬油菜＞冬小麦＞麦茬＞,春播最差.因此,推广冬油菜、冬小麦等越冬作物的种植是解决我国北方风蚀区农田土壤风蚀、土地沙漠化以及根治沙尘暴尘源的有效途径和措施.

Wind erosion-resistance of fields planted with winter rapeseed in the wind erosion region of Northern China

Wind erosion is very severe in some regions of Northern China. This study was conducted to determine wind-resistance of fields planted with winter rapeseed using a simulated wind tunnel experiment. Treatments included four typical farmland surfaces, i.e., winter rapeseed, winter wheat, wheat stubble without crop, and spring seeding of rapeseed; all being in Hexi Corridor, Northern China., The results showed that the degrees of roughness for winter rapeseed, winter wheat, wheat stubble and spring seeding were 4.2, 4.1, 3.9, and 0.7, respectively; starting wind speeds were 14, 13, 12, and 6 m?s-1, respectively; mean values of modulus of wind erosion were 22.3, 23.3, 42.5, and 543.6 kg?hm-2?h-1, respectively; and the rates of transportation were 0.1, 0.1, 0.2, and 23.3 g?m-2?min-1, respectively. Furthermore, by that the roughness and the starting wind speed change from bigger to little, and that the modulus values of wind erosion and rates of transportation change from little to bigger, Based on these four parameters described above, the wind erosion-resistance of these four farmland surfaces can be ranked in order of: winter rapeseed > winter wheat > wheat stubble > spring seeding. Our results suggest that in order to reduce soil wind erosion, desertification and the sources of sand and dust storms, in the windy regions of Northern China, one should firstly adapt those crops living through the winter periods, including winter rapeseed and winter wheat, especially winter rapeseed; and secondly one should decrease the area of spring seeding as much as possible; and thirdly spread wheat stubble area to the areas where spring wheat has been traditionally planted using tillage practices.