树盘施肥区域大小对15 N吸收利用及桃幼树生长的影响

摘要

[Objectives]In this study, the effects of fertilization area size on absorption and utilization of nitrogen and suitable fertilization pattern in peach orchard were evaluated to provide the beneficial reference for peach cultivation production.[Methods]Two-year-old peach trees, Spring Snow, and 15 N isotope tracer technique were used to investigate the effects of fertilization area changes on the absorption and the utilization of 15 N and growth of young peach trees. The tree plate was evenly divided into four areas in the horizontal direction using the tree backbone as a center. Seven treatments was designed, including 1/4, 2/4, 3/4 and 4/4 root zone fertilization, fixed root-zone fertilization, root-zone alternative fertilization and the no fertilizer treatment. Peach tree stem was regularly measured during growing season, and the plant was collected and subdivided into abover-ground and under-ground parts corresponding to fertilization area and non-fertilization area at the end of the test. Above-ground part is subdivided into shoot, leaf and stem corresponding to different root area, and under-ground part is subdivided into coarse roots (≥0. 2 cm diameter ) , fine roots ( <0. 2 cm diameter ) , and dry matter biomass of different organ is weighed.[Results]The result showed that the nitrogen utilization rate in the 4/4 root zone ( full tree plate) is 4. 16%, which is respectively 3. 62, 1. 65 and 1. 24 times of those in the 1/4, 2/4 and 3/4 root zones. The nitrogen utilization rate in the fixed root-zone fertilization is 1. 24 times of that in the root-zone alternative fertilization. After the local fertilization treatment, Ndff value in the root system and 15 N distribution rate in fertilization area are significantly higher than those in the non-fertilization area. There are no significant differences between the15 N distribution rate and Ndff value in above-ground part from new born organ in the fertilization area and the non-fertilization area. The total root try matter in fertilization area is less than that in the non-fertilization area. Generally, the plants growing in the full tree plate fertilization have the maximum growth rate , the plants growing in the fixed root-zone fertilization and the root-zone alternative fertilization are similar in the growth rates. The plant growth rate in the 4/4 root zone ( full tree plate) is 0. 57 cm/month, which is respectively 1. 19, 1. 14 and 1. 04 times of those in the 1/4, 2/4 and 3/4 root zones. [Conclusions]Nitrogen utilization rate and plant growth rate in the full tree plate fertilization are the highest, i. e. the uniform fertilizer treatment is recommonded for nutrient utilization and morphogenesis of young peach trees.%【目的】探讨树盘施肥区域大小对氮素吸收与分配的影响以及适合桃园的施肥模式,以期为桃树栽培生产提供有益的参考。【方法】在大田栽培条件下,以2年生“春雪”桃为试材,以主干为中心,在水平方向把树盘均匀分为东西南北4个区,设置1/4、2/4、3/4、4/4根区施肥以及固定根区施肥和根区交替施肥,以不施肥处理为对照,共7个处理。生长季定期测定桃树干茎,试验结束时,破坏性整株取样,解析为各施肥区与非施肥区对应的地上部和地下部,地上部解析为对应根区的枝、叶和干；地下部解析为对应根区的粗根(直径>0.2 cm)和细根(直径≤0.2 cm),烘干后测定各部分干重。应用15 N同位素示踪技术,研究树盘施肥区域大小对15 N吸收利用及桃幼树生长的影响。【结果】4/4根区(全树盘)施肥氮肥吸收利用率为4.16%,分别为1/4、2/4、3/4根区施肥的3.62倍、1.65倍和1.24倍；固定根区施肥氮肥吸收利用率是根区交替施肥的1.24倍。局部施肥处理,施肥区根系的Ndff值高于非施肥区根系的Ndff,差异显著；施肥区根系的15 N分配率高于非施肥区根系的15 N分配率,差异显著；施肥区对应的地上部新生器官的15 N分配率和Ndff值与非施肥区对应的地上部新生器官的15 N分配率和Ndff值均无显著差异。施肥区的根系总干重均小于非施肥区根系的总干重。总体以全树盘施肥处理植株生长速率最大,4/4根区(全树盘)施肥植株生长速率为0.57 cm/month,分别为1/4、2/4、3/4根区施肥的1.19倍、1.14倍和1.04倍；根区固定施肥与根区交替施肥处理植株生长速率无显著差异。【结论】全树盘施肥氮肥吸收利用率最高,植株生长速率最大,即均匀施肥有利于桃幼树对养分的吸收利用,利于桃幼树形态建成,促进树体生长发育。