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以两年生红富士/平邑甜茶为试材,采用田间小区试验及15N同位素标记示踪法,研究了低氮(50 kg·hm-2)和中氮(100 kg·hm-2)条件下分别种植3种牧草(白三叶、黑麦草和鼠茅草)对苹果幼树生长及15N–尿素吸收、利用的影响。结果表明,春梢停长期,与单作苹果相比,种植牧草后苹果植株生物量、吸氮量及15N肥料利用率显著降低,这在低氮处理下尤为明显;而到秋梢停长期,与单作苹果相比,种植牧草后苹果植株生物量、吸氮量、15N肥料利用率及根系活力显著提高。至秋梢停长期,0~20cm土层15N丰度及总氮含量为种植白三叶>种植鼠茅草>种植黑麦草>单作苹果,而在20~40 cm及40~60 cm土层15N丰度及总氮含量为单作苹果>种植黑麦草>种植鼠茅草>种植白三叶,表明种植白三叶、黑麦草和鼠茅草降低了氮素的淋溶损失,有利于氮肥的保持,从而提高氮肥利用率,促进苹果幼树的生长。
The two-year-old Red Fuji / Pingyi sweet tea were used as materials to study the effects of low nitrogen (50 kg · hm-2) and medium nitrogen (100 kg · hm-2) on field plot and 15N isotope labeling The effects of three kinds of herbage (white clover, ryegrass and rat thatch) on the growth and 15N-urea absorption and utilization of young apple trees were respectively studied. The results showed that compared with monoculture apples, the shoot biomass, N uptake and 15N fertilizer utilization rate of apples decreased significantly after spring shoots were stopped, especially under low nitrogen treatments. However, Compared with monoculture apple, the plant biomass, N uptake, 15N fertilizer utilization rate and root vitality increased significantly after planting forage. In the long-term stand, the 15N abundance and total nitrogen in 0 ~ 20cm soil layer ranged from white clover> planted shrubs> planted ryegrass> monoculture apples, while in 20-40 cm and 40-60 cm soil layers The abundance and total nitrogen content of white clover were planted monocotyledons> ryegrass> ryegrass> white clover, which indicated that the planting of white clover, ryegrass and rat grass reduced the leaching loss of nitrogen and was favorable for the maintenance of nitrogen fertilizer. Thereby increasing the utilization of nitrogen fertilizer and promoting the growth of young apple trees.