不同水肥一体化方式对苹果氮素吸收利用特性及产量和品质的影响

以‘嘎啦/八棱海棠’为试材,借助¹⁵N同位素示踪技术,研究了撒施(T₁)、滴灌施氮(T₂)和渗灌施氮(T₃)对嘎啦苹果氮素吸收利用、分配特性和产量品质的影响,以期进一步完善苹果园水肥一体化技术,挖掘提高氮素利用率的途径。结果表明: T₃处理苹果叶片的叶面积、叶绿素和氮含量显著高于T₁和T₂处理。各时期土壤矿化氮(N_min)含量在20~40 cm土层表现为T₃＞T₂＞T₁处理,在0~20 cm土层表现为T₂＞T₃＞T₁处理。同一器官的Ndff值(树体各器官从肥料中吸收到的¹⁵N占该器官全氮量的比例)在各时期均以T₃处理最高,T₂其次,T₁处理最低。果实成熟期的树体¹⁵N利用率表现为T₃＞T₂＞T₁处理,其中T₃处理的树体¹⁵N利用率为24.2%,分别是T₂和T₁处理的1.19和1.65倍。果实成熟期T₁处理的¹⁵N分配率在营养器官最高,T₂处理在贮藏器官最高,T₃处理在生殖器官最高。各处理的单果重、产量、可溶性固形物、硬度、可溶性糖及糖酸比均以T₃处理最高,T₂其次,T₁处理最低。渗灌施氮处理显著促进了嘎啦苹果树体叶片生长和氮素利用,并提高了果实产量和品质。

Effects of different integration of water and fertilizer modes on the absorption and utilization of nitrogen fertilizer and fruit yield and quality of apple trees

We examined nitrogen use efficiency of ¹⁵N-urea of 15-year-old ‘Gala’ apple trees by broadcast fertilization (T₁), nitrogen fertilization with drip irrigation (T₂) and nitrogen fertilization with subsurface irrigation (T₃), to further improve the water and fertilizer integration technology for apple orchard and to improve nitrogen utilization efficiency. The results showed that leaf area, chlorophyll, and leaf nitrogen content of leaves were significantly higher in T₃ treatment than those in T₁ and T₂ treatments. Soil mineral nitrogen content (20-40 cm) in each period followed the order of T₃>T₂>T₁, while that in 0-20 cm followed an order of T₂>T₃>T₁. The Ndff value at organ level (the contribution rate of the ¹⁵N amount absorbed by various organs of the tree to the total nitrogen content of the organ) was the highest in T₃ treatment in each period, followed by T₂ and T₁ treatments. The utilization rate of ¹⁵N in the fruit ripening period followed an order of T₃>T₂>T₁. The ¹⁵N utilization rate of T₃ reached 24.2%, being 1.19 and 1.65 times of T₂ and T₁, respectively. The ¹⁵N distribution rate in the fruits during the fruit maturity stage was the highest in T₁ treatment, while that in the storage organs was the highest in T₂ treatment and that in the reproduction organs was the highest in T₃ treatment. The single fruit weight, yield, soluble solids, hardness, soluble sugar and sugar-acid ratio were the highest in T₃ treatment, followed by T₂ and T₁ treatments. In summary, nitrogen application by percolation irrigation (subsurface application) significantly promoted leaf growth and nitrogen utilization of apple tree, and improved fruit yield and quality.