LAUSR

BACKGROUND Water shortage is the main factor affecting agricultural production in the vast arid and semi-arid areas of northern China. Using proper irrigation methods can optimize the efficiency of water use and improve the quality of agricultural products. This study investigated the effect of different irrigation levels on the quality of 'Honeycrisp' apples grown in the Loess Plateau of northern China. RESULTS Different irrigation levels were applied to the 'Honeycrisp' apple trees via root irrigation using ceramic emitters that provide saturation levels of 75%θf -90%θf (S1, where θf is the field capacity), 60%θf -75%θf (S2), 45%θf -50%θf (S3), and no irrigation treatments (CK). Compared to the apples from the CK group, the water content, transverse diameter, individual fruit weight, and titratable acid content of S1 and S2 group apples increased significantly. However, their hardness, soluble solids, and total sugar content decreased significantly. The phenolic acid content of apples also changed with the irrigation levels. The chlorogenic acid content of apples increased with increased irrigation volume, while the hyperoside, protocatechuic acid, and caffeic acid content decreased. Total phenolic and flavonoid contents of fruits were the highest in S2 group apples. They also had the strongest ABTS and DPPH free radical scavenging capacities. CONCLUSION The volume of irrigation applied through ceramic emitters significantly impacted the quality of 'Honeycrisp' apples grown in loess areas. Considering water conservation and improving fruit quality, the most suitable ceramic root irrigation level was observed to be 60%θf -75%θf (S2). This article is protected by copyright. All rights reserved.