施氮对设施栽培金针菜产量、品质和钾吸收利用的影响

Effects of nitrogen application rate on yield, quality, potassium uptake and utilization of daylily(Hemerocallis citrina Baroni) in protected cultivation

【目的】明确施氮对设施栽培金针菜产量、品质和钾吸收利用的影响,为设施栽培金针菜的养分管理提供理论依据。【方法】以金针菜‘大乌嘴’为试验材料,于2015—2017年在江苏省宿迁市丁嘴镇江苏省农业科学院金针菜试验基地进行了田间试验。设5个施氮量处理(N0、50、100、150和200kg/hm^2,以N0、N50、N100、N150、N200表示)。在返青期、抽薹期和现蕾期采样分析了金针菜产量、品质和钾的吸收利用。【结果】增施氮肥提高了金针菜不同生育阶段的钾吸收量,以抽薹到现蕾期钾吸收量增量最大。与N0相比,N50、N100、N150和N200处理下的钾吸收量分别增加21.0%、67.6%、86.0%和103.8%,处理间差异达到显著水平。施氮改变了不同生育时段的钾吸收比例,使返青到抽薹期的钾吸收比例降低,抽薹到现蕾期的钾吸收比例升高,其中N200处理下效果最显著。增施氮肥降低了现蕾期生育后期钾浓度的下降速率,其中,N0、N50、N100、N150和N200处理下表示钾浓度降低趋势的b值分别为0.0051、0.0048、0.0045、0.0044和0.0042。随施氮量增加,钾吸收的边际效应呈先升高后降低趋势,而钾的生产效率呈直线降低趋势。N100、N150处理的金针菜积累的干物质和钾量在花蕾中的分配比例较高,钾浓度和钾累积量动态特征参数比较协调,利于产量形成,且VC、氨基酸、可溶性糖、黄酮和多酚含量相对较高;N200kg/hm^2处理导致金针菜产量增幅下降,氮素钾吸收边际效应和钾的生产效率降低,但秋水仙碱含量最高;低于N100kg/hm^2时,干物质和钾的总吸收量及经济系数较低,不利于高产形成。【结论】供试条件下,施用氮肥N100~150kg/hm^2可减缓金针菜生育期后期钾吸收的下降,提高钾吸收边际效应、钾的生产效率和金针菜的品质。

【Objectives】The purpose of this study was to identify the effects of nitrogen (N) application rate on yield, quality, potassium (K) uptake and utilization of daylily (Hemerocallis citrina Baroni) in protected cultivation, to provide theoretical support for nutrient management techniques in protected cultivation.【Methods】Experiments were conducted from 2015 to 2017 at the daylily experimental station of Jiangsu Academy of Agricultural Sciences (Dingzui Town, Suqian City, Jiangsu Province). The daylily cultivar used in the experiment was ‘Dawuzui’. Five application rates of N 0, 50, 100, 150 and 200 kg/hm^2 (expressed as N0, N50, N100, N150, N200) were designed. The yield, quality, K uptake and utilization of daylily were analyzed at the re-greening, bolting and budding stages.【Results】The N application increased the K uptake at all growth stages, and the largest increment occurred during bolting to budding stage. Compared to N0, the K uptake with N50, N100, N150 and N200 treatments significantly increased by 21.0%, 67.6%, 86.0% and 103.8%, respectively.Nitrogen application also changed the ratio of K uptake at the monitoring stages. The ratio of K uptake decreased from re-greening to bolting stage, while increased from bolting to budding stage, and N200 showed the most significant effect among the treatments. Increase of N application rate alleviated the K decrease rate at budding stage, the b values obtained in the treatments of N50, N100, N150 and N200 were 0.0051, 0.0048, 0.0045, 0.0044 and 0.0042, respectively. As the N application rate increased, the marginal effect of K uptake (i.e. increased amount of K uptake by 1 kg increase of N application) increased first and then decreased, and the daylily production efficiency of K descended steadily. In the treatments of N100 and N150, the daylily dry matter accumulation was high and more K was allocated to the reproductive organs, and the dynamic characteristic parameters of K concentration and accumulation were more optimized, which was beneficial for the yield formation and higher contents of vitamin C, amino acids, soluble sugars, flavones, and polyphenols. In the treatment of N150, the marginal effect of K uptake and production efficiency decreased, while the content of colchicine reached the highest. In treatments N0 and N50, the yields reduced, and K accumulation and economic coefficient of biomass of daylily decreased significantly, compared with other treatments.【Conclusions】Under the tested condition, nitrogen application rate of 100–150 kg/hm^2 could promote the accumulation and transport of K, alleviate the decrease rate of K uptake in the later growth stage of daylily, thus beneficial to the formation of yield and quality related compounds as result.