不同生育期水分亏缺耦合施氮量对花生光合特性和品质的影响

为探究不同生育期水分亏缺和施氮量对花生光合特性、产量及品质的影响,于2020和2021年设置测坑裂区试验,研究充分灌溉（IF,灌水下限为田间持水率的70%～75%）和调亏灌溉（IRD,花针期和饱果期控水下限均为田间持水量的55%～60%）下,施氮量（0（N0）、50（N50）、100（N100））kg/hm2）对花生光合速率、蒸腾速率、产量及品质的影响。研究结果表明,与充分灌溉相比,花针期调亏灌溉降低了花生叶片光合速率和蒸腾速率;结荚期复水后,由于补偿效应,调亏灌溉处理的光合速率和蒸腾速率均高于充分灌溉。调亏灌溉耦合100 kg/hm2氮肥处理（IRDN100）显著提高了花针期和结荚期的光合速率和蒸腾速率（P?0.05）,且花生产量最高,较传统水氮处理（IFN100）2 a平均提高了13.4%（P?0.05）。与传统水氮处理相比,IRDN100处理生产的花生具有相对较高的蛋白质、油脂、油酸、亚油酸含量及油亚比,即出油量和储存品质均较好。因此,IRDN100处理不仅能节水增产,还能改善花生品质,可为干旱半干旱地区实现花生节水提质增效生产目标提供理论参考。

Effects of water deficit in different growth stages coupling with nitrogen application rates on photosynthetic traits and quality of peanuts

Regulated deficit irrigation has been ever increasingly utilized to cope with the limited irrigation water resources for better crop production. This study aimed to explore the effects of water deficit in different growth stages with the nitrogen application rates on the photosynthetic characteristics, yield, and quality of peanuts. A split-plot experimental design was conducted in the lysimeters at the Experimental Farm of College of Water Conservancy of Shenyang Agricultural University, Shenyang, China, during the 2020 and 2021 peanut growing seasons (May to October). An investigation was made on the effects of nitrogen application rates (0 (N0), 50 (N50), and 100 kg/hm2 (N100)) on the photosynthetic rate, transpiration rate, yield, yield components, and quality of peanut under different levels of water deficit (full irrigation, IF, the lower limit for irrigation was 70%~75% field capacity; regulated deficit irrigation, IRD, the lower limit for irrigation at the flowering and pod filling stages was 55%~60% field capacity)). The soil moisture content was monitored at the 5-day interval during the peanut growing season. The photosynthetic rate and transpiration rate of peanut leaves were determined at the flowering and pod setting stages, respectively, using the Li-Cor 6400 portable photosynthesis measurement system. Three pieces of leaves were selected for determination each time. After harvest, the peanut yield and yield components were determined at the 14% moisture on a per-plot basis. The Near Infrared Quality Analyzer was also utilized to determine the peanut quality, including the protein, oil, oleic acid, linoleic acid content, and Oleic-Linoleic ratio (O/L). The clustering analysis was performed to identify the correlations between the different peanut quality traits under different irrigation and nitrogen treatments using the "pheatmap" package in R studio software. The results showed that the regulated deficit irrigation reduced the photosynthetic rate and transpiration rate of peanut leaves at the flowering stage, compared with the full irrigation. After rehydration at the pod setting stage, the photosynthetic rate and transpiration rate in the regulated deficit irrigation treatment was higher than those in the full irrigation due to the compensatory effect. The N100 significantly increased the photosynthetic rate and transpiration rate under regulated deficit irrigation at the flowering and pod setting stages, compared with the non-nitrogen control. Consequently, the regulated deficit irrigation significantly increased the peanut yield, 100 fruit weight, and 100 kernel weight, compared with the full irrigation. The highest peanut yield was achieved in the regulated deficit irrigation coupled with the 100 kg/hm2 nitrogen fertilizer treatment (IRDN100), which was 13.4% higher than that of the traditional water and nitrogen treatment (IFN100) (two-year average). The peanut produced in the IRDN100 treatment presented a relatively higher protein, oil, oleic acid, linoleic acid content, and O/L, indicating better oil output and storage quality. Therefore, the IRDN100 treatment can be expected to save water for the high peanut yield and quality. The finding can provide a theoretical reference for the water-saving, quality-improving, and efficiency-increasing in peanut production in arid and semi-arid areas.