Monitoring fruit growth online with smart farming

Smart Dendro: Apple and Tomatoe

Internet connected sensors measure fruit growth in real time. These data will be used to optimise the management of orchards and greenhouses.

Agroscope’s experience in dendrometry (measuring the development of plants and, by extension, of a specific organ, stem, trunk, fruit, etc.) continues through a partnership with the Swiss company JDC Electronics SA, based in Yverdon. Sensors developed specifically for fruit are currently undergoing development and testing at Agroscope in Conthey (D. Tran, C. Camps and P. Monney) as part of an INNOSUISSE project. These sensors using the Internet of Things (IoT) allow continuous remote monitoring of fruit expansion with a high degree of accuracy (±0.1mm).

The physiological state of the plant and its environment (water status, nutrient availability, weather conditions, etc.) play a crucial role in growth. The latter slows down or even reverses at the hottest time of day, as illustrated by observations made (see graphs) during the recent heat wave that struck Europe in late June 2019.

Smart Dendro Graphic: Apple - Tomatoe
Diameter and temperature of an apple and a tomato between June 27 and July 3, 2019
Small graph: diameter and temperature of a tomato from the beginning to the end of the growth

Apples grow during the night

Irrespective of the weather conditions, growth takes place daily in two phases: a phase of diameter increase, followed by a contraction phase of smaller measure. In apples, most of the growth happens during the night and up until mid-morning. Growth slows down at night, then speeds up during the morning and stops at midday.

Greenhouse tomatoes grow in the morning

In tomato plants grown in a controlled greenhouse environment, these contraction and expansion phases follow one another with sometimes greater amplitude. The expansion phase takes place from early morning until early afternoon. During this phase, a rapid linear growth rate takes place.

This approach makes it possible to characterise different growth dynamics between fruits species. These dynamics are subject to variations in environmental conditions, cultivation practices and potential stresses. The project goes on to study the potential of this tool as a decision aid to fine-tune the management of crop conditions (climate, irrigation, etc.).