In-plant probe of water potential for feedback controlled management of water status in fruit crops

Water is a critical and growing issue for our planet in both human use as well as the need for food production to feed a growing world population. Agriculture plays a dominant role in this challenge as the single largest user of water, accounting for an estimated 70% of all use by humans. There are 680 million acres of irrigated agriculture in the world (FAO) and 55 million acres of irrigated crops in the US alone. With climate change and increasing drought frequency, improving agricultural water use efficiency is truly a critical global issue. To optimize water use efficiency requires the ability to measure how much water stress the crop is experiencing and limit the amount of water used in irrigation without detrimental effects on crop yield or quality. Precision irrigation is one of weakest components of precision agriculture due to a lack of ways to directly monitor crop water stress. This project is a collaborative effort between nanotech engineering and applied plant science that has developed an innovative new technology, called a microtensiometer, for continuously monitoring water stress in plants. This is a micro-chip based on a well-understood principle of measuring the water. Due to the design and manufacturing method, this microtensiometer has a huge range of accurate measurement, faster equilibration times (seconds), and much smaller size than existing systems. Such a tiny sensor can be embedded directly inside the stems of plants, especially woody crops, and provide continuous real-time data on water stress wirelessly to growers. We have been testing the sensor inside grapevines, almond trees and apple trees and have proven that this technology works over many months in the harsh commercial field environments. The measurements give the same values as a current standard, but manual and slow, method. The continuous monitoring of crop stress will provide unprecedented actionable information to growers for efficient decision-making in smart management systems in multiple agricultural, forestry and ornamental uses. This will be key to improving irrigation efficiency, reducing environmental damage due to leaching, optimizing product yield and quality, and maintaining sustainability for irrigated crops.