水肥配比对大枣氮素分布及利用效率的影响

Effect of the Ratio of Water-Fertilizer Nitrogen Distribution and Utilization Efficiency in Jujube Trees

为研究水肥耦合对矮化密植大枣氮素分布及利用效率的影响,以13 a树龄的大枣为试材,采用15N示踪法,进行大田试验,设置3个灌溉水平:正常水量(70%～80%田间持水率FC)、轻度水分亏缺(50%～60%FC)和中度水分亏缺(40%～50%FC); 3个施肥水平:高氮420 kg/hm2、中氮330 kg/hm2和低氮240 kg/hm2,共9个处理。试验结果表明:在相同的肥料配比下,轻中度水分胁迫可增强大枣植株对氮肥的吸收能力,在相同水分处理条件下,不同肥料配比对15N丰度影响较小,差异未达到显著水平。相同肥料配比下,轻中度水分胁迫可提高器官的肥料贡献率值;同时植株的氮肥利用率也最高;经过此次试验研究发现,灌溉水量为900 mm、施氮肥420 kg/hm2的水肥处理为最优组合,建议在大枣生产管理中按此配比进行水肥管理,增加氮素积累,以提高氮肥利用率,保障树体营养生长。该研究可为矮化密植大枣实施有效的滴灌施肥管理提供理论依据。

In order to study the effect of water and fertilizer coupling on the nitrogen distribution and utilization efficiency of jujube trees,the jujube of 13 a age was used as test material,the15 N tracer method was used for the field experiment,three irrigation levels,including normal water（ 70% - 80% FC）,mild water deficit（ 60% - 70% FC） and moderate water deficit（ 50% - 60% FC）,and three fertilization levels,including high nitrogen（ 420 kg/hm2）,medium nitrogen（ 330 kg/hm2） and low nitrogen（ 240 kg/hm2）,totaling 9 treatments were set.The results showed that： under the same fertilizer ratio,light and moderate water stress could enhance the uptake of nitrogen fertilizer in jujube plants; under the same water condition,the ratio of different fertilizers had a certain effect on the15 N abundance,and the difference did not reach the significant level; under the same fertilizer ratio,light and moderate water stress could increase the fertility rate of the organ;at the same time,the nitrogen use efficiency of the plant was the highest. According to the results,it is suggested that the irrigation water quantity of 900 mm with the nitrogen fertilizer of 420 kg/hm2 is the best fertilizer and water ratio; the fertilizer and water management should be carried out in the management of jujube to improve the utilization of nitrogen fertilizer rate,increase nitrogen accumulation,and protect the tree vegetative growth. The study can provide theoretical basis for effective drip irrigation and fertilization management of dwarf close planting jujube.