膜下滴灌调亏在提升河西绿洲洋葱产量及品质的应用

为探究膜下滴灌调亏对河西绿洲洋葱品质和产量的影响,以红宝903洋葱为试验材料,采用不同生育期和不同梯度调亏灌溉方式二因素随机区组试验设计,共9个处理。在每个生育期测定洋葱光合参数,收获后测定洋葱产量及品质。结果表明:(1)发叶和鳞茎膨大期水分亏缺显著降低了洋葱叶片净光合速率、蒸腾速率和胞间CO_2浓度,且降幅随水分亏缺程度加大而增大。(2)水分亏缺造成洋葱产量不同幅度降低,调亏处理中成熟期轻度水分亏缺产量最高(47 940 kg/hm~2),其次为苗期轻度水分亏缺(46 521 kg/hm~2),分别较充分灌溉降低5.93%和8.71%(P0.05)。(3)苗期轻度水分亏缺灌溉水利用效率最高(58.84 kg/m~3),成熟期轻度水分亏缺次之(52.60 kg/m~3),分别较充分灌溉显著提高36.14%和21.70%(P0.05)。(4)苗期轻度水分调亏处理的洋葱综合品质最佳,其紧实度、洋葱油、可溶性糖、可溶性蛋白、维生素C和丙酮酸含量较生育期充分灌溉提高3.06%,2.50%,10.40%,17.57%,4.35%和6.06%。因此,综合考虑产量、水分生产效率、产值及果实品质等指标,通过运用主成分分析法进行综合评价,表明洋葱最佳水分调控处理为苗期轻度水分胁迫,即在苗期保持土壤相对含水率70%～75%、其余生育期土壤相对含水率为80%～85%。该研究可为实现河西走廊绿洲灌区洋葱高效节水栽培和产业化发展提供理论与技术参考。

Application of Mulched Drip Irrigation Under Water Deficit in Improving the Productivity and Quality of Onion in Hexi Corridor

To uncover the effect of mulched drip irrigation under water deficit on the yield and quality of onion in Hexi corridor,a field experiment was conducted taking Hongbao 903 as study object. The experimental employed a two-factor randomized blocks design of mulched drip irrigation with different water deficit gradients in growth periods,which included nine treatments totally. Onion photosynthetic parameters in every growth period were measured,and the onion productivity and quality were determined after harvest. Results showed that: (1) Water deficiency (WD) in the development and bulbification stages obviously decreased net photosynthetic rate,transpiration rate and intercellular CO₂concentration,and the reduction increased with the raise of water deficiency. (2) WD decreased yield in different degree. Slight water deficit in ripening stage was the highest (47 940 kg/hm²),secondly in the establishment satge (46 521 kg/hm²),of which decreased by 5.93% and 8.71% (P>0.05) respectively compared with full irrigation. (3) Slight water deficit in the establishment period gave the highest irrigation efficiency (58.84 kg/m³),secondly in ripening stage (52.60 kg/m³),of which increased by 36.14% and 21.70% respectively compared with full irrigation. (4) The onion quality was the best under the treatments of slight water deficit in the establishment stage,indicated by the increased compactness,onion oil,soluble sugar,soluble protein,vitamin C and pyruvic acid,by 3.06%,2.50%,10.40%,17.57%,4.35% and 6.06% respectively,compared with full irrigation. Taking the productivity,water product efficiency,output value and fruits quality,etc. altogether,the principal component analysis was used for comprehensive evaluation. The slight water deficit in the establishment stage was an ideal stage for soil moisture regulation. There lative soil water content should be kept around 70%~75% in the establishment stage,and 80%~85% in others. These results could provide the theoretical and technical references for the water saving planting ofonion and its industrialization development.