Assessing almond response to irrigation and soil management practices using vegetation indexes time-series and plant water status measurements

Current water scarcity scenario has led to the implementation of sustainable agricultural practices intended to improve water use efficiency. The present work evaluates during three agricultural campaigns (2018–2020) the response of a young almond orchard to two management practices in terms by combining remote sensing indexes (Normalized Difference Vegetation Index, NDVI; and Soil Adjusted Vegetation Indexes, SAVI) and physiological/morphological measurement (stem water potential, Ψstem; trunk perimeter and canopy diameter). The management practices included (i) sustained deficit irrigation and (ii) soil management. Severe deficit irrigation resulted in lower vegetation indexes (VI) values, Ψstem and tree dimensions (13 %, 23 % and 14 % lower, respectively) than those obtained for full irrigation strategy; whereas moderate deficit irrigation did not affect any of the parameters analysed. The presence of vegetation cover in the inter-row resulted in a VIs increase (19–42 %) and in lower tree dimensions (reductions of 7–8 % for trunk perimeter and 0.34–0.37 m for canopy diameter) when compared to bare soil treatment, but did not have any influence on Ψstem. The present study proves the suitability of remote sensing and physiological measurements for assessing almond response to the different management practices.

This research was funded in the frame of the projects PRECIRIEGO RTC-2017–6365-2 financed by Agencia Estatal de Investigación with European Regional Development Fund co-funds; and the European Union H2020 project SHUI GA 773903. The research was supported also by the CajaMar Caja Rural Contract “Efficient use of water resources under climate change scenarios”. I. Buesa and J.M. Ramírez-Cuesta acknowledge the postdoctoral financial support received from Juan de la Cierva Spanish Postdoctoral Program (FJC2019–042122-I and IJC2020–043601-I, respectively). Authors acknowledge David Hortelano and José Luis Ruíz García for the help provided in the field measurements acquisition. This work represents a contribution to CSIC Thematic Interdisciplinary Platform PTI TELEDETECT.