Real-time Continuous IoT-TT Spectrum as a Predictor of Plant Health and Fruit Quality in 'Soreli' Kiwifruit

Abstract

The kiwifruit, for which Italy is the second largest producer in the world, is derived from a fruit vine that requires a significant amount of water for proper growth and the production of high-quality fruit. This study aims to investigate the ideal irrigation strategy to ensure an adequate water supply for robust root development, vibrant foliage, and successful fruit production. To achieve this goal, three experimental plots of Soreli kiwifruit vineyards were subjected to different water regimes: full irrigation (100%) and two plots with 80% and 60% irrigation. Each irrigation group was equipped with an Internet of Things (IoT) TT Spectrum, which measured reflected spectrometer data in 12 bands. Additionally, a soil sensor was used to determine moisture content. Fruit quality analysis, including weight loss, soluble solid content, flesh color and firmness, titratable acidity, ascorbic acid, polyphenols and flavonoids, was conducted to correlate productivity with water availability. By analyzing the IoTTT Spectrum data for each kiwifruit plant, crucial indicators for assessing physiological status, health, and growth were examined. Maintaining a balance between leaf nitrogen content and photosynthetic capacity, with low AI and higher NDVI and CVI values, was used to determine the optimal irrigation level for each of the three plots. Furthermore, qualitative data obtained from fruits revealed that overwatering or underwatering kiwifruit plants affects yield production and fruit quality. Fruits subjected to full irrigation exhibited lower sugar levels compared to those under deficit irrigation. This study demonstrates that excessive or limited irrigation regimes negatively impact plant health and on the fruit quality