河套灌区代表性地下水盐分与灌水量对枸杞产量及品质的影响

为明确不同微咸水水质下枸杞种植效益较高的灌水量范围,揭示枸杞干果产量、外观品质、营养品质在微咸水不同盐浓度和灌水量下的变化规律,该研究对河套灌区不同代表性地下水盐分与灌水量组合下的枸杞干果产量、外观品质、营养品质进行综合评价。基于L8（41×24）正交表在河套灌区开展2 a田间试验,共设置8个处理,灌水量为4个水平（60、70、80和100 mm）,典型盐（NaCl、CaCl2、NaHCO3、Na2SO4）浓度设置为2个水平（分别按研究区地下水中离子浓度的1、2倍水平调配）。结果表明：1）干果产量、百粒干质量、果形指数、鲜干果比、黄酮含量受灌水量影响较大;产量、总糖含量受NaCl影响较大,随NaCl升高而降低;类胡萝卜素、甜菜碱、氨基酸总量受CaCl2影响较大,随CaCl2浓度升高而升高。2）综合评分发现,高灌水、高CaCl2的T8处理营养品质贴合度Cpi和种植效益贴合度Ci最高,而高灌水、高NaCl浓度的T5处理两指标均最低。Ci分别与Ca2+、Na+浓度极显著正、负相关（P<0.01）,与Cl-显著负相关（P<0.05）。Ca2+主要促进枸杞营养品质发展,与黄酮、类胡萝卜素、甜菜碱、氨基酸总量极显著正相关,Na+、Cl-主要抑制产量、外观品质,分别与干果产量、百粒干质量极显著、显著负相关。3）高斯回归发现,Na+、Ca2+、Cl-浓度分别为34.8～38.8、15.3～15.6、50.9～55.9 mmol/L的微咸水较适宜,单次灌水96.9～97.9 mm下种植效益贴合度Ci>0.7;基于与Ci显著相关的Na+、Ca2+、Cl-浓度,提出了不同离子条件下枸杞种植效益较高的灌水量。研究结果可为河套灌区因地制宜利用微咸水、提高枸杞种植效益提供科学依据。

Effects of representative groundwater salinity and irrigation amount on the yield and quality of Lycium barbarum in the Hetao Irrigation areas

Abstract: Lycium barbarum fruit is widely used as a medicinal food in China. This study aims to clarify the effects of brackish water irrigation amount and salt ion composition on the yield, appearance quality, and nutritional quality of the Lycium barbarum. An optimal amount of brackish water was also determined under different water qualities, according to the comprehensive score after irrigation simulation. A L8 (41×24) orthogonal test was carried out with the "Ningqi No.1" Lycium barbarum as the test material. Eight orthogonal treatments included the four irrigation levels (60, 70, 80, and 100 mm) and two concentrations (according to 1 or 2 times of ion concentration in groundwater in the study area) of NaCl, NaHCO3, Na2SO4, and CaCl2. The optimal levels of each factor were obtained and scored for each index, including the yield, 100 grains dry mass, and nutritional quality. The greatest correlation with the comprehensive score was selected as the salt ions. A gaussian regression model was established for the sensitive ion concentration and comprehensive score Ci, in order to obtain the optimal irrigation quantity range under different water quality using the screening program. The water quality and irrigation quantity scheme achieved higher scores than before. The results showed that there were significant effects of the brackish water irrigation amount and the concentrations of NaCl, NaHCO3, Na2SO4, and CaCl2 on the yield, dry mass of 100 grains, and nutritional quality. In the yield and appearance quality, the irrigation amount presented the most significant effects on the dry fruit yield, dry mass of 100 grains, fruit shape index, and dry fruit ratio. The maximum yield and dry mass of 100 grains were achieved at the irrigation amount of 70mm, and 100 mm, respectively. The NaCl effect on the dry fruit yield was higher than that of the rest salts. The maximum yield was reached at the N1 level. In the nutritional quality, the concentration of CaCl2 was dominated by the total amount of carotenoids, betaine, and amino acids, the highest of which was C2 (0.24%, 15.2 g/kg, and 11.67 g/100g, respectively). NaCl was determined as the total sugar, the highest which was the N1. The highest amount of flavonoids was obtained at the irrigation amount of 100mm. The comprehensive score showed that the T8 (W4, C2, HC1, N1, and S2) treatment with the high water. The CaCl2 presented the highest nutritional quality (Cpi=0.895), and planting benefit (Ci=0.719). The T5 treatment with the high water and NaCl was the lowest (Cpi=0.172, Ci=0.200). Ci was very negatively correlated with the concentration of Na+ (P<0.01), and Cl- (P<0.05), whereas, there was a very significant positive correlation with the concentration of Ca2+ (P<0.01). Ci was significantly positively and negatively correlated with Ca2+ and Na+ concentrations, respectively, and negatively correlated with Cl-. Gaussian regression showed that the brackish water with the concentrations of Na+, Ca2+, and Cl- of 34.8-38.8, 15.3-15.6, and 50.9-55.9 mmol/L were better suitable for irrigation, compared with the planting benefit fit Ci>0.7 with 96.9-97.9 mm in the single irrigation. The optimal irrigation amount was achieved under different water quality: In the Cl- content of 63.02-81.50 mmol/L, the Na+ contents were 18.55-30, 30-35, 35-40, 40-53, and 53-55 mmol/L, where the optimal irrigation amount was 91-98, 82-98, 77-83, 77-99, and 96-98 mm. In the Cl- content of 81.50-99.11 with the Na+ contents of 18.55-30 and 35-55 mmol/L, the optimal irrigation amount was 97-99 and 69-77 mm. In the Na+ content of 30-35 mmol/L with the Ca2+ concentrations of 8.77-13.00 and 13.00-17.54 mmol/L, the optimal irrigation amount was 74-98 and 78-82 mm. The findings can provide a scientific basis to utilize the brackish water for the better planting benefits of Lycium barbarum in the Hetao Irrigation area.