板蓝根耗水特性和其产量及品质对膜下滴灌调亏的响应

研究旨在通过大田试验了解水分调亏对膜下滴灌板蓝根生长、耗水规律、产量、水分利用效率及品质的影响。于2018年在甘肃河西中部的民乐县益民灌溉试验站开展板蓝根水分控制试验,在板蓝根苗期和肉质根生长期保持充分灌水,营养生长期和肉质根生长期分别进行不同梯度(轻度、中度和重度)的水分调亏处理,并测定各项生长指标、产量、水分利用效率和品质。结果表明:(1)营养生长期和肉质根生长期中度和重度水分调亏显著降低了板蓝根株高、叶片数、主根长和主根直径,且降幅随调亏程度的加剧而增大,而轻度水分调亏与对照组无显著差异。(2)板蓝根在营养生长期和肉质根生长期各处理的耗水量呈现出随着水分调亏程度的加重而逐渐降低趋势,与对照相比降低显著(P<0.05);耗水强度变化次序为营养生长期和肉质根生长期(约3.0 mm/d)>肉质根成熟(约1.5 mm/d)>苗期(约1.0 mm/d)。(3)营养生长期轻度水分调亏处理的板蓝根产量与水分利用效率最高,分别达到8475.38 kg/hm^2和23.33 kg/(hm^2·mm),营养生长期和肉质根生长期连续轻度水分调亏处理次之,其余水分调亏处理产量和水分利用效率均有所下降,且与对照组之间差异显著(P<0.05)。(4)在营养生长期和肉质根生长期轻中度连续水分调亏有利于靛蓝、靛玉红、(R,S)-告依春、多糖含量的提高,且与对照组差异显著(P<0.05),重度水分调亏处理各项指标均最低。因此,综合分析板蓝根产量、水分利用效率和品质可知,最优控水处理为营养生长期和肉质根生长期连续轻度水分调亏,即该阶段土壤相对含水率为65%~75%,可作为河西冷凉灌区板蓝根种植的最佳灌水策略。

Responses of Water Consumption Characteristics, Yield, and Quality of Isatis tinctoria to Mulched Drip Irrigation Under Water Deficit

The effects of water deficit (WD) on the growth, water consumption, yield, water use efficiency, and quality of Isatis tinctoriaunder-mulche drip irrigation were studied by a field experiment. In 2018, the I.tinctoria water control experiment was carried out at the Yimin Irrigation Experimental Station in Minle County, Gansu Province. The seedling stage and the fleshy root growth period were fully flooded, and different gradients (mild, moderate and severe) WD treatment were carried out in the vegetative growth period and the fleshy root growth stage , and various growth indicators, yield, water use efficiency and quality were determined. The results showed that: (1)In the period of vegetative stage and fleshy root growth, the moderate and severe water deficit significantly reduced the plant height, leaf number, main root length, and main root diameter, and the declines increased with the raising WD level, While the mild WD treatment showed no significant difference compared with control group. (2)The water consumption of I. tinctoria in the period of vegetative and the fleshy root growth decreased gradually with the increasing of WD regulation, which was significantly lower than the control group (P<0.05). The order of water consumption intensity change was that: the vegetative and the fleshy root growth (about 3.0 mm/d) > the fleshy root maturity (about 1.5 mm/d) > the seedling (about 1.0 mm/d). (3)In the vegetative period, the mild WD treatment (V₁G₀) had the highest yield and water use efficiency, reaching 8 475.38 kg/hm² and 23.33 kg/(hm²·mm), respectively, and the treatment of V₁G₁ followed, and yield and water use efficiency of the remaining treatments decreased significantly (P<0.05). (4) In the vegetative stage and the fleshy root growth stage, mild and moderate continuous WD was beneficial to the indigo, indirubin, (R, S)-goitrin, and the polysaccharide content was significantly different from the control group (P<0.05). The indicators of severe WD treatment were the lowest. Therefore, comprehensive analysis of I. tinctoria yield, water use efficiency and quality,the optimal water-control treatment is the continuous slight WD in the vegetative growth period and the fleshy root growth period(V₁G₁), That is to say, the relative water content of the soil during this period is 65%~75%, which can be used as the optimal irrigation strategy for the planting of I. inctoria in the cool irrigation area of Hexi.