College of Water and Soil Conservation, Beijing Forestry University, Beijing, PR China.
PLoS One. 2013 Jul 25;8(7):e70739. doi: 10.1371/journal.pone.0070739. Print 2013.
Agroforestry has been widely practiced in the Loess Plateau region of China because of its prominent effects in reducing soil and water losses, improving land-use efficiency and increasing economic returns. However, the agroforestry practices may lead to competition between crops and trees for underground soil moisture and nutrients, and the trees on the canopy layer may also lead to shortage of light for crops. In order to minimize interspecific competition and maximize the benefits of tree-based intercropping systems, we studied photosynthesis, growth and yield of soybean (Glycine max L. Merr.) and peanut (Arachis hypogaea L.) by measuring photosynthetically active radiation, net photosynthetic rate, soil moisture and soil nutrients in a plantation of apple (Malus pumila M.) at a spacing of 4 m × 5 m on the Loess Plateau of China. The results showed that for both intercropping systems in the study region, soil moisture was the primary factor affecting the crop yields followed by light. Deficiency of the soil nutrients also had a significant impact on crop yields. Compared with soybean, peanut was more suitable for intercropping with apple trees to obtain economic benefits in the region. We concluded that apple-soybean and apple-peanut intercropping systems can be practical and beneficial in the region. However, the distance between crops and tree rows should be adjusted to minimize interspecies competition. Agronomic measures such as regular canopy pruning, root barriers, additional irrigation and fertilization also should be applied in the intercropping systems.
在中国黄土高原地区，由于其在减少水土流失、提高土地利用效率和增加经济回报方面的显著效果，农林复合经营得到了广泛应用。然而，农林复合经营可能会导致作物和树木对地下土壤水分和养分的竞争，冠层的树木也可能导致作物光照不足。为了最小化种间竞争，最大限度地提高基于树木的间作系统的效益，我们通过测量苹果（Malus pumila M.）种植园（株行距为 4 m×5 m）中的光合有效辐射、净光合速率、土壤水分和土壤养分，研究了大豆（Glycine max L. Merr.）和花生（Arachis hypogaea L.）的光合作用、生长和产量。结果表明，在所研究的地区，对于两种间作系统，土壤水分是影响作物产量的主要因素，其次是光照。土壤养分的缺乏也对作物产量有显著影响。与大豆相比，花生更适合与苹果树间作，以在该地区获得经济效益。我们得出结论，苹果-大豆和苹果-花生间作系统在该地区是实用且有益的。然而，应该调整作物和树木行之间的距离，以最小化种间竞争。在间作系统中，还应该采取农业措施，如定期树冠修剪、根障、额外灌溉和施肥。
