Effects of different nutrition supply on growth, nitrogen uptake and partitioning of pot cultured nectarine

【Objectives】 Nitrogen partitioning coordinates with growth center of fruit trees, obvious differences in the N partition exist between organs of growing center and non-growing center with traditional base plus dressing fertilizer method. Use of controlled release fertilizer and drip fertilization make a steady nutrition supply comes true. Effects of different nutrition supply methods on potted culture nectarine growth, nitrogen uptake and partitioning at the same amount of nitrogen fertilizer input were studied for better understanding of new fertilization technology in nectarine production. 【Methods】 One-year old nectarine trees (Prunus persica Batsch, var. nectarine) of cv. Luxingyihao were planted in pots filled with 40 L of siliceous sand. Steady nutrition supply (SS) was obtained through packing fertilizer inside a bag with holes. Non-steady nutrition supply (nSS) was from the conventional splitting application of commercial fertilizer. Shoots were divided into two parts (upper and lower parts) as their location in stems. Nitrogen uptake and partitioning of upper and lower shoots after 30 days and 150 days of the processing were determined with 15N isotope tracer technique. 【Results】 Thirty days and one hundred and fifty days after the steady nutrition supply, the biomass amounts of nectarine plants are 63.49 g per tree and 160.74 g per tree respectively, the ratios of upper and lower part shoots biomass are 1.8 and 1.3 respectively, and the longest lengths of new shoots are 169.73 cm per tree and 306.55 cm per tree respectively. One hundred and fifty days after different fertilization methods treated, the differences in the new shoot length and their biomass among the treatments are significant and extremely significant, respectively. The biomass of upper shoots under the steady nutrition supply is increased by 98% between two sampling intervals, the biomass amounts under the non-steady nutrition supply and the control are increased by 93% and 42%, respectively, and the biomass amounts of lower shoots under the steady nutrition supply, non-steady nutrition supply and control are increased by 177%, 45% and 8%, respectively. During this period the ratios of upper to lower biomass of the control treatment, nutrition non-steady supply and nutrition steady supply are changed from 5.0 to 6.6, 2.8 to 3.7 and 1.8 to 1.3, respectively. The plant nitrogen uptake amounts under the steady nutrition supply are 12.7 and 76.9 mg per plant at the 30 days and 150 days after the processing, and those are 4.0 and 27.3 mg per plant treated with non-steady nutrition supply. The highest nitrogen use efficiency is obtained with the steady nutrition supply treatment, which reaches 12.96%, and that with the non-steady nutrition supply only reaches 4.6%. The nitrogen contents in upper shoots and leaves and the percentages of nitrogen derived from fertilizer are higher than those in lower shoots and leaves. The differences in nitrogen concentration of shoots and leaves between the upper part and lower part are extremely different (P0.01) 150 days after the treatment. The nitrogen derived from fertilizer and the nitrogen concentration are same between upper and lower shoots and leaves of the same plant, and are different at P0.01 of the steady and non-steady treatments when sampled after processing 150 days. Partitioning ratios of the nitrogen uptake between upper and lower are significantly different under the steady and non-steady nutrition supply treatments and are 1.54 and 4.03 respectively. 【Conclusions】 Compared with non-steady nutrition supply, the polar growth is little, and nitrogen uptake increases, nitrogen recovery rate increases, and the nitrogen partitioning difference between growth center and non-growth center decreases under the nutrition steady supply.