探明镁元素对马铃薯产量的影响，为马铃薯生产中镁肥科学施用提供依据。以马铃薯品种庄薯3号和青薯10号为试验材料，设置了叶面喷施硫酸镁1.05、1.50、1.95 kg/hm2以及喷等量清水为对照4个处理，研究了不同处理对马铃薯株高、大中薯率和产量的影响。结果表明，喷施硫酸镁能有效促进马铃薯株高，提高马铃薯产量和大中薯率。庄浪县、渭源县试验点产量和大中薯率均以喷施硫酸镁1.50 kg/hm2最高，其中产量分别为28 667.17、57 223.39 kg/hm2，分别较清水喷洒增产6.7%、5.5%；大中薯率分别为84.3%、76.9%，分别较清水喷洒增加9.4、9.2个百分点。因此，在庄浪县和渭源县试验点喷施硫酸镁1.50 kg/hm2更有利于马铃薯株高、大中薯率和产量增加。可在马铃薯生产上推荐施用。

This study aimed to determine the appropriate phosphorus application rate for purple-leaf lettuce in the high-humid mountain areas of Lanzhou, providing a scientific basis for high-quality and efficient production as well as soil health improvement in lettuce production. 4 treatments were included: low phosphorus(144 kg/ha), medium phosphorus(180 kg/ha), high phosphorus (216 kg/ha), and a control (CK, no phosphorus application), and application rate effect on the yield and quality of purple-leaf lettuce were studied. Results showed that compared with the control, plant height, stem diameter, yield, free amino acid content in stems, and vitamin C content under phosphorus treatments were increased by 5.34% to 11.48%, 18.07% to 34.92%, 37.80% to 52.44%, 8.01% to 39.50%, and 4.08% to 12.91%, respectively. The medium phosphorus level (180 kg/ha) resulted in the highest values in plant height, stem diameter, single plant weight, yield, stem free amino acids, and vitamin C content, followed by the high phosphorus level (216 kg/ha). The nitrate content under the low phosphorus level (144 kg/ha) was 4.95% lower than the control, while the 180 and 216 kg/ha treatments increased nitrate content by 78.22% and 103.96%, respectively. In summary, the medium phosphorus level demonstrated the best performance in terms of key parameters, yield, and quality of purple-leaf lettuce in the high-humid mountain areas of Lanzhou. Under nitrogen application of 525 kg/ha and potassium oxide(K2O) of 375 kg/ha, the optimal phosphorus pentoxide(P2O5) application rate is 180 kg/ha, which is recommended for local adoption.

S532

甘肃省现代农业科技支撑体系区域创新中心项目(2021GAAS53)。