退耕还林不同人工林类型对土壤养分的影响

对内蒙古敖汉旗2006年退耕还林的樟子松纯林、山杏纯林、山杏沙棘混交林和荒草地（对照）不同深度的土壤养分状况进行研究,结果表明：3种人工林的土壤有机质和碱解氮含量明显增加,山杏沙棘混交林中沙棘林带表层的速效磷含量明显增加,山杏纯林浅层的速效钾含量明显增加;3种人工林和荒草地的土壤养分随着土壤深度的增加而降低,表层土壤养分条件较好,说明土壤养分具有很强的表聚性;3种人工林与荒草地相比都不同程度地提高了土壤养分水平,樟子松纯林和山杏沙棘混交林中沙棘林带的土壤养分条件较好.

Effects of conversing farmland to forest on soil nutrition in different forest type

In this study, the soil nutrition was investigated in P/nus sylvestris var. mongolica pure plantation, Prunus sibirica pure planta- tion, P. sibirica and Hippophae rhamrdodes mixed plantation, and naturally restored grassland （as control） in Aohanqi which were con- versed farmland to forest in 2006. The results indicated that：the conlents of soil organic matter and alkafi-hydrolyzable N were in- creased significantly in three plantations. In mixed forest, the available P was increased in H. rhamn/odes. The available K was in- creased in shallow soil in Prunus sibirica plantation.The soil nutrition in plantations and grassland were decreased with the increasing of soil depth, and displayed soil surface gathering characteristics.The contents of soil nutrition were higher in the three kinds of planta- tion than in grassland. And the nutrition situations were better in Pinus sylvestris var. mongolica pure forest and H. rhamn/odes of mixed forest.