黄土丘陵沟壑区林草间作对土壤养分的影响——以甘肃省庄浪县为例

Soil nutrient dynamics affected by tree intercropping with grass in the loess hill and gulch area:A case study in the Zhuanglang County of Gansu Province

以不同林草间作模式为对象,以相同立地条件下的农田作为对照,对林草间作地土壤养分变化进行了测定分析,结果表明:在黄土高原丘陵沟壑区实施林草间作,在一定程度上有利于提高土壤养分含量和营养水平.5种间作模式对土壤养分含量和营养水平的影响程度大小依次为:山杏×紫花苜蓿>山杏×红豆草>油松×紫花苜蓿>油松×红豆草>沙棘×紫花苜蓿;林草间作对土壤有机质和土壤全氮含量的影响较为显著,而对土壤全磷、全钾含量的影响相对较小;从影响的土层深度看,林草间作对40 cm以上土壤养分含量的影响要比对60 cm层的影响更为明显.

The tree intercropping with grass has been widely applied at the project of converting farmland to woods in the loess hill and gulch area. The objective of this research was to investigate the dynamics of soil nutrients under tree intercropping with grass in comparison with farmland. The results indicated that tree-grass intercropping had increased soil nutrient contents and nutrient level in certain degree. The effect degree of intercropping patterns on soil nutrient and level arranged as follows： Prunus. armeniaca var. ansu intercropping with Medicage. sativa, Prunus. armeniaca var. ansu intercropping with Onobrychis viciae f olia , Prunus. tabulae f ormis intercropping with Medicago sativa , Prunus tabulae f ormis intercropping with Onobrychis viciae f olia , Hippophae rhamnoides subsp, sinensis intercropping with Medicag sativa. The intercropping had more prominent impact on soil organic matter and total nitrogen than on total phosphorus and total potassium,and it had more prominent impact on the soil nutrient contents at the soil layer of 0-40 cm depth than 40-60 cm depth.