Effects Of Soil Organic Matter On Growth,Physioloy And Mineral Element Absorption Of Young Apple Tree

China is the world’s largest producer of apple, which occupies an important position in the world production of apple. Northwestern loess plateau, one of the most important regions in the production of apple in China, belongs to arid and semi-arid area where in low use efficiency of fertilizer and water is one of the biggest limiting factors impacting sustainable development of the apple industry. Therefore, it is a vital importance to research the utilization of fertilizer in apple orchard. In this study, we choose 3-year-old potted‘Nagafu No.2’apple(Malus domestica Borkn. cv. Red Fuji) trees on Malus Robusta rootstocks with M26 inter-stock as the test material, apply four kinds of levels(1.5%, 2%, 2.5% and 3%) of soil organic matter and nitrogen fertilization, to investigate the effects on apple seedlings growth, physiology and absorption of mineral elements. The main results are as follows:1. It was found that when the concentration of soil organic matter is 3%, the chlorophyll content, specific leaf weight, root activity, soil microbial bacteria and actinomycetes,accumulation of mineral elements in the leaves of apple saplings, photosynthetic rate, the maximum photochemical efficiency(Fv/Fm) of light system in the apple leaves and the relative electron transport rate(ETR) increased significantly, while soil microbial fungi and non-photochemical quenching(NPQ) dramatically reduced.2. After applying the same amount of urea(32g/strain) on 3% level of soil organic matter concentration, the chlorophyll, specific leaf weight, photosynthetic rate, root activity,the amount of microbial fungi and actinomycetes as well as the accumulation of mineral elements showed the best effect, which also dispalied good interaction effect between organic matter and N interaction, while the quantity of microbial bacteria declined.3. It was found in this study that there was no threshold of the soil organic matter during growth of apple saplings. Soil organic matter can not only provide some nutrients that the plants need, but also directly or indirectly affect the mineral elements absorption of apple saplings. It is speculated that the high soil organic matter can reduce the application of fertilizers, and it can be appropriately combined application of phosphate and potassium fertilizer during growth process of apple saplings.