Nutrient patterns can significantly influence the growth and development of fruit trees, especially fruit quality. In order to clarify the appropriate ratio of inorganic and organic fertilizers, six treatments with different ratios of cow manure and chemical fertilizers were set up in this study to evaluate the effects of different treatments on fruit yield, appearance quality, intrinsic quality and volatile substances. The results showed that, after replacing some chemical fertilizers with cow manure, the content of sugar, titratable acid, organic acid and aroma substance in the fruit increased, the fruit yield and colour did not change significantly, and the fruit weight per fruit decreased. Among the treatments of cow manure with chemical fertilizer, the fruits of 50% chemical fertilizer with 50% cow manure treatment had higher titratable acid (0.4%), malic acid (4.15 mg/g), sorbitol (0.51%), glucose (1.30%), fructose (5.81%) content and total aroma substance content (1047.82 μg/g) than chemical fertilizer alone. Compared to the fertilizer treatment alone, the application of cow manure instead of 50% of the chemical fertilizer had a positive effect on fruit quality.

Leaves directly reflect the nutritional status of apple tree growth. Though China is a major apple producer, existing data on standard apple leaves are usually simple records of selected varieties over discontinuous time periods, which cannot present a comprehensive or holistic view. Hence, it is particularly valuable to build an image and near infrared spectrum (NIS) dataset for standard leaves of apple varieties. The study collects high-definition images and NIS data of healthy standard leaves from over 170 apple varieties at a national apple resource repository, and processes and categorizes the data to build a dataset with a maximum coverage of apple varieties. In doing so, it is expected to provide statistical support for nutrient diagnosis and precise nutrient management of apple leaves.