Abstract:

A total of 114 leaf samples from 20‘Xuxiang’kiwifruit orchards in central Shaanxi Province were analyzed for element concentration at the late fruit development stage in 2020，and at three stages of the leaf expansion，fruit enlargement and late fruit development in 2021. Based on the leaf norm values developed by high and stable yield and high quality，the leaf nutrient status was diagnosed using three methods：diagnosis and recommendation integrated system （DRIS），deviation from optimum percentage（DOP），and compositional nutrient diagnosis（CND）. Additionally，probability grading method，one derivative method of sufficiency range method，was used to determine the sufficient range of leaf elements for‘Xuxiang’kiwifruit. This study provides a scientific basis for annual nutrient resource management in‘Xuxiang’kiwifruit production. The results indicated that leaf element concentration was significantly different between various growth stages，and there were significant correlations between leaf element concentration and fruit yield，fruit quality as well as vine growth performance. Fourteen samples were selected as high-productivity populations from 114 samples，based on the functional relationships between leaf element analytic parameter and fruit yield，comprehensive fruit quality score as well as vine growth performance，established by CND cutoff method. The results from DRIS，DOP and CND indicated that，the remaining 100 leaf samples of low-productivity populations were deficient in Ca and Fe but excessive in Mn，Cl and P during the leaf expansion stage，deficient in N and Ca but excessive in Mg and Cl at the fruit enlargement stage，and deficient in Ca but excessive in Cl，Mn and N at the late fruit development stage. The sufficient ranges of leaf elements in ‘Xuxiang’kiwifruit were developed using probability grading method：at the leaf expansion stage，N 35-40 g · kg^-1，P 3.0-3.8 g · kg^-1，K 21-26 g · kg^-1，Ca 15-20 g · kg^-1，Mg 2.5-3.0 g · kg^-1，Cl 3.0-4.5 g · kg^-1，Fe 100-180 mg · kg^-1，Mn 50-80 mg · kg^-1，Cu 14-20 mg · kg^-1，Zn 21-30 mg · kg^-1 and B 32-45 mg · kg^-1；at the fruit enlargement stage，N 29-35 g · kg^-1，P 1.4-1.8 g · kg^-1，K 9-16 g · kg^-1，Ca 37-44 g · kg^-1，Mg 6.0-7.8 g · kg^-1，Cl 3.5-5.5 g · kg^-1，Fe 175-250 mg · kg^-1，Mn 85-200 mg · kg^-1，Cu 8.5-15.0 mg · kg^-1，Zn 15-30 mg · kg^-1 and B 55-85 mg · kg^-1；at the late fruit development stage，N 20-24 g · kg^-1，P 1.3-1.7 g · kg^-1，K 7-14 g · kg^-1，Ca 42-51 g · kg^-1，Mg 7-9 g · kg^-1，Cl 3-5 g · kg^-1，Fe 180-250 mg · kg^-1，Mn 80-160 mg · kg^-1，Cu 7-12 mg · kg^-1，Zn 20-45 mg · kg^-1 and B 52-67 mg · kg^-1.

Key words: kiwifruit, leaf nutrient diagnosis, diagnosis and recommendation integrated system, deviation from optimum percentage, compositional nutrient diagnosis, sufficiency range