Irrigating for Sustainable Intensive Agriculture: Technological Approaches.

Abstract

Proper irrigation scheduling requires and accurate determination of when and how much to irrigate. This is crucial in a context of sustainable intensive agriculture, where management decisions have a great impact on crop development and production. The issue becomes specially challenging when the water available for irrigation is below the crop water requirements and a deficit irrigation strategy must be applied. Under these conditions, the choice of both the irrigation strategy and the scheduling irrigation method highly determines the success of irrigation. Here we focus on high performance methods to assess the crop water stress and to schedule irrigation, based on measurements in the soil, in the plant or in the atmosphere. We review both the fundamentals and characteristics of new sensors and related equipment, including installation, maintenance and data processing requirements. We pay especial attention to plant-based sensors related to sap flow, trunk diameter variations or leaf turgor pressure, due to the potential of using the plant as a biosensor for assessing water stress. Then we address how these methods should be combined with remote imagery, since identifying the spatio-temporal variability within the orchard, of soil and plant variables related to water stress, is crucial for precision irrigation. Finally, we address socioeconomic aspects related to the level of acceptance of these new methods by growers.