白于山区仁用杏基地建设探讨

根据杏属3个树种杏(鲜食杏)、仁用杏和西伯利亚杏在白于山区的树体生长量,根系分布,不完全花比例,花期不遇及花期遭遇霜冻时的坐果率和经济产值比较,认为仁用杏可作为该区的生态环境建设的搭配树种,不可列为基地建设树种。

陕北白于山山区仁用杏引种观测与评价

Armeniaca vulgaris × A. sibirica is a new almond-apricot species of Armeniaca genus in Baiyushan mountainous area of northern Shaanxi that introduced from Zhuolu County, Hebei Province 12 years ago. After 11 years investigated and observed, the florescence of A. vulgaris × A. sibirica is the earliest and the shortest compared with A. vulgaris , A. vulgaris var . ansu and A.sibirica ; the number of non-harvest year caused by frost is the most; number of root is the least, and root distribution is lowest and narrowest; trunk diameter, height, and crown diameter are the least; almond is changed smaller and smaller with the tree age increased; production of stone is lower than A. vulgaris var . ansu and A.sibirica ; in small hilly region and medium mountain regionⅠ, production value is lower than A. vulgaris and higher than A. vulgaris var . ansu and A.sibirica ; in medium mountain regionⅡ, production value is lower than A. vulgaris var . ansu and A.sibirica ,very lower than A. vulgaris . A. vulgaris × A. sibirica shouldn’t be a dominating species in Baiyushan mountainous area.

退耕还林(草)以来陕北白于山区植被覆盖与土壤侵蚀强度变化

为了研究白于山区土壤侵蚀特征,基于MODIS-NDVI和Landsat影像、DEM和土地利用数据,分析了白于山区2000-2018年植被盖度时空变化规律,并结合坡度和土地利用资料评估了退耕还林(草)工程以来的土壤侵蚀强度变化状况。结果表明:(1)白于山区植被覆盖呈显著增加趋势,年均NDVI增幅为0.065/10 a(p<0.01);(2)白于山区NDVI具有明显的空间分异性,高植被覆盖区主要集中在吴起县,低植被覆盖区主要集中在定边县西部和靖边县中部;受到地形因子的影响,NDVI分别在海拔1250~1400 m,坡度50°~56°范围内达到最大值,且阴坡植被覆盖大于阳坡;(3)白于山区植被盖度整体呈显著增加趋势,植被退化面积与恢复面积分别占研究区面积的3.18%,64.20%;(4)白于山区轻度侵蚀和中度侵蚀的面积减少,但强烈侵蚀、极强烈侵蚀和剧烈侵蚀的面积增加;(5)土壤侵蚀强度减弱的面积占总面积的51.30%,主要集中在吴起县,农耕地面积的减少是土壤侵蚀改善的主要原因。