Assessment of yield and water productivity of clementine trees under surface and subsurface drip irrigation

Irrigation systems aimed to optimize water use efficiency in agriculture have become essential due to the increasing water limitations that agriculture is currently facing. Assessment of crop responses to different irrigation systems and strategies are therefore encouraged to find the most efficient options for each specific case. The main objective of this study was to assess the performance of a citrus crop under a surface (SI) and subsurface drip irrigation (SSI) with 7 (SI7, SSI7) or 14 emitters (SI14, SSI14) per plant, as well as a third SS treatment (SSIA), identical to SSI7 but equipped with and additional drip line buried between the tree rows. Evaluations were made in terms of yield, fruit composition, irrigation water productivity (IWP) and water savings. Results showed that, on average, water savings were 23.0% in the SSI treatment compared to the SI treatment without significant differences in either yield or fruit composition. IWP was higher in SI14, SSI14 and SSIA than in SI7 and SSI7 treatments. SSIA was the treatment with the lowest irrigation volumes and the highest yield and compared to SI7 allowed, over the three years, water savings in the range between 22.4 and 27.9%. Results from this study illustrate that there is opportunity to substantially save water in citrus production and that further research in this direction is needed to contribute to better optimize the water resources in agriculture.