库尔勒香梨树在不同生育期的氮肥利用率

Nitrogen utilization rate of Korla fragrant pear trees in different growth periods

【目的】研究库尔勒香梨树对氮素的吸收与利用特征,从而为香梨园的优化施肥、促使香梨树对氮素吸收和利用效率的提高及香梨产业的优质高效发展提供参考依据。【方法】设置不同的氮肥(N)用量(分别为0、150、300、450 kg·hm-2)处理(编号分别为N0、N1、N2、N3),分别采用农学差减法和同位素示踪法对6年生库尔勒香梨不同生育期的氮肥利用率进行分析。【结果】与不施氮肥的相比,施氮可显著促进库尔勒香梨树体的生长,尤其是对当年新生器官叶片和果实的生物量及氮素的吸收积累影响均较显著。在果实成熟期,树体地下、地上部分的干物质量和果实中的氮素净积累量、15N积累量及香梨产量,均以N2处理的为最高;而整株树体的氮素净积累量、15N积累量,均以N3处理的为最高。不同氮肥用量处理下库尔勒香梨树在不同生育期对氮肥的利用率,均表现为以农学差减法计算得出的值大于以同位素示踪法计算得出的值,但两者差别不大,且其变化规律相同。新梢旺长期,分别以差减法和示踪法计算得到的氮肥利用率,随着施氮量的增加均减小,其中N1处理的均最大。果实膨大期,随着施氮量的增加,分别以差减法和示踪法计算得到的氮肥利用率均表现出先增长后下降的变化规律,其中N2处理的均最大;以农学差减法计算得到的不同氮肥用量处理下库尔勒香梨树对氮肥的利用率为15.97%~18.10%,以15N同位素示踪法计算得到的不同氮肥用量处理下库尔勒香梨树对氮肥的利用率为14.32%~17.17%。果实成熟期,不同氮肥用量处理下库尔勒香梨树对氮肥的利用率的变化规律同果实膨大期的一致,也以N2处理的为最大;以农学差减法和15N同位素示踪法计算得到的库尔勒香梨树对氮肥的利用率分别为16.92%~20.99%和15.58%~20.19%。【结论】适量施氮能显著促进库尔勒香梨的树体生长及产量形成,并能提高氮肥利用率。研究结果表明:以氮肥施用量为300 kg·hm-2处理的库尔勒香梨在其成熟期的产量和氮肥利用率均最高。

【Objective】The nitrogen absorption and utilization characteristics of Korla fragrant pear trees was studied to provide reference for optimizing fertilization,promoting the nitrogen absorption and utilization efficiency,and developing the high-quality and efficient Korla fragrant pear industry.【Method】Different amounts of nitrogen fertilizer(N)treatment(0,150,300,450 kg·hm-2,equivalent to N0 N1,N2,and N3,respectively)were set up to analyze the nitrogen fertilizer utilization rate of 6-year-old Korla fragrant pear at different growth stages by agronomic subtraction method and isotope tracer method.【Result】Compared with non-nitrogen fertilizer application,nitrogen application significantly promoted the growth of Korla fragrant pear,especially on the biomass and nitrogen absorption and accumulation of leaves and fruits of the current year.At the fruit maturity stage,the dry matter of the underground and above ground parts,the net nitrogen accumulation and 15N accumulation of fruit and yield were the highest under N2 treatment,while the net nitrogen accumulation and 15N accumulation of the whole tree was the highest under N3 treatment.The nitrogen fertilizer utilization rate under different nitrogen application rates showed that the agronomic subtraction method was greater than the isotope tracer method at different growth stages,but the difference was not significant,and the variation was similar.In the new shoot growing stage,the nitrogen fertilizer utilization rate of the subtraction method and the tracer method decreased with the increase of nitrogen application rate,which was the largest under N1 treatment.At the fruit swelling stage,the nitrogen fertilizer utilization rates all showed firstly increasing and then decreasing with the increase of nitrogen application rate,among which,N2 treatment resulted the highest.The range of nitrogen fertilizer utilization rate under different nitrogen fertilizer treatments was 15.97%-18.10%by agronomic subtraction method,and the range was 14.32%-17.17%15N isotope tracer method.During the fruit maturity stage,the nitrogen fertilizer utilization rate under different nitrogen application rates was consistent with the swelling stage,and N2 treatment resulted the highest.The range of nitrogen fertilizer utilization rates obtained by agronomic subtraction method and 15N isotope tracer method was 16.92%-20.99%and 15.58%-20.19%,respectively.【Conclusion】Appropriate nitrogen application can significantly promote tree growth and yield formation,and improve nitrogen fertilizer utilization rate.In this experiment,under the condition of 300 kg·hm-2nitrogen fertilizer application rate,the yield and nitrogen fertilizer utilization rate of Korla fragrant pear at the mature stage are the highest.