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Abstract：
In the production of economic forests, there are common issues such as excessive application of water and fertilizer, redundant plant growth, and low economic benefits. Reasonable water and fertilizer management can not only help address these problems but also improve the absorption and use efficiency of water and fertilizer resources by plants, promoting the green and efficient development of the fruit and forestry industry. In order to explore a suitable water and nitrogen management mode for Lycium barbarum, field experiments were conducted in this study from 2021 to 2022. Specifically, four irrigation modes (according to the proportion ratio of soil moisture content to field moisture capacity θf, 45-55% θf (W1, severe water deficiency), 55-65% θf (W2, moderate water deficiency), 65-75% θf (W3, mild water deficiency), and 75-85% θf (W4, sufficient irrigation)) and four nitrogen application levels (0 kg·ha-1 (N0, no nitrogen application), 150 kg·ha-1 (N1, low nitrogen application level), 300 kg·ha-1 (N2, medium nitrogen application level), and 450 kg·ha-1 (N3, high nitrogen application level)) were set up to analyze the influences of water and nitrogen control on the plant height, stem diameter, chlorophyll content, photosynthetic characteristics and yield, and economic benefits of Lycium barbarum in the Lycium barbarum + Alfalfa system. The study results show that the plant height and stem diameter increment of Lycium barbarum increase with the irrigation amount, increasing first and then decreasing with the increase in the nitrogen application level. Meanwhile, the chlorophyll contents in Lycium barbarum continuously increase throughout their growth periods, with Lycium barbarum treated with W4N2 during all growth periods presenting the highest contents of chlorophyll. In a Lycium barbarum + Alfalfa system, the daily variation curve of the Lycium barbarum net photosynthetic rate presents a unimodal pattern, with maximum values of the daily average net photosynthetic rate and daily carboxylation rate appearing among W4N2-treated plants (19.56 μmol·m-2·s-1 and 157.06 mmol·m-2·s-1). Meanwhile, the transpiration rates of Lycium barbarum plants continuously decrease with the increased degree of water deficiency and decreased nitrogen application level. W1N2-treated plants exhibit the highest leaf daily average water use efficiency (3.31 μmol·s-1), presenting an increase of 0.50-10.47% in efficiency compared with plants under other treatments. The coupling of water and nitrogen has significantly improved the yields and economic benefits of Lycium barbarum plants, with W4N2-treated and W3N2-treated plants presenting the highest dried fruit yield (2623.07 kg·ha-1) and net income (50,700 CNY·ha-1), respectively. Furthermore, compared with other treatment methods, these two treatment methods (W4N2 and W3N2) exhibit increases of 4.04-84.08% and 3.89-123.35% in dried fruit yield and net income indexes, respectively. Regression analysis shows that, in a Lycium barbarum + Alfalfa system, both high yields and economic benefits of Lycium barbarum plants can be achieved using an irrigation amount of 4367.33-4415.07 m3·ha-1 and a nitrogen application level of 339.80-367.35 kg·ha-1. This study can provide a reference for improving the productivity of Lycium barbarum plants and achieving a rational supply of water and nitrogen in Lyciun barbarum + Alfalfa systems in the Yellow River Irrigation Area of Gansu, China, and other similar ecological areas.
摘要：
在经济林生产中,有常见的问题，如过度施用水和肥料，多余的植物生长，经济效益低。合理的水肥管理不仅有助于解决这些问题,而且可以提高植物对水肥资源的吸收和利用效率,促进果林产业绿色高效发展。为探索适宜枸杞水氮管理的模式,本研究于2021年至2022年进行了现场实验。具体来说,四种灌溉模式(根据土壤水分含量与田间水分容量的比例θf，45-55%θf(W1,严重缺水),55-65%θf(W2,中度缺水),65-75%θf(W3,轻度缺水),和75-85％θf（W4，充分灌溉）和四个氮素施用水平（0kg·ha-1（N0，无氮施用），150kg·ha-1（N1，低氮水平），300kg·ha-1(N2,中等施氮水平),并设置450kg·ha-1（N3，高氮施用水平））来分析水氮控制对株高的影响，阀杆直径,叶绿素含量，光合特性和产量，枸杞+苜蓿系统中枸杞的经济效益。研究结果表明，枸杞的株高和茎径增量随着灌水量的增加而增加，随着施氮量的增加先增加后减少。同时,枸杞的叶绿素含量在整个生长期不断增加，在所有生长期中，用W4N2处理的枸杞的叶绿素含量最高。在枸杞+苜蓿系统中，枸杞净光合速率的日变化曲线呈单峰型,在W4N2处理的植物中出现每日平均净光合速率和每日羧化速率的最大值（19.56μmol·m-2·s-1和157.06mmol·m-2·s-1）。同时,枸杞植株的蒸腾速率随着缺水程度的增加和施氮水平的降低而不断降低。W1N2处理的植物表现出最高的叶片日平均水分利用效率（3.31μmol·s-1），与其他处理下的植物相比，效率提高了0.50-10.47％。水氮耦合显著提高了枸杞植株的产量和经济效益,W4N2处理和W3N2处理的植物表现出最高的干果产量（2623.07kg·ha-1）和净收入（50,700CNY·ha-1），分别。此外，与其他治疗方法相比，这两种处理方法(W4N2和W3N2)的干果产量和净收入指标分别提高了4.04-84.08%和3.89-123.35%，分别。回归分析表明,在枸杞+苜蓿系统中，使用4367.33-4415.07m3·ha-1的灌溉量和339.80-367.35kg·ha-1的施氮量，可以实现枸杞植物的高产和经济效益。本研究可为提高甘肃引黄灌区枸杞植株的生产力,实现枸杞+苜蓿系统水、氮的合理供应提供参考,中国,和其他类似的生态区。
