Transformation of Terraces with Irrigation Systems: Profitability and Water Savings in Potato Crop (Solanum tuberosum L.)

Abstract

In recent decades, climate change has intensified the challenges in agriculture, increasing the incidence of water and heat stress during critical stages of the crop cycle. It includes the exacerbation of the seasonality of rainfall and temperature. This significantly affects their development and yield. In addition, climate change has reduced irrigation water availability, highlighting the need to evaluate joint strategies to increase water productivity. These strategies include the implementation of irrigation systems, the use of terraces, and the application of deficit irrigation (DI). In this context, the present research aims to evaluate the irrigation water productivity (WPirri) and the economic water productivity (EWP) of the combined use of DI through a pressurized irrigation system in terraces of the southern highlands of Peru for a potato crop. The treatments included L0: traditional surface irrigation with irrigation depth equivalent to 100% ETc, L1: drip irrigation with irrigation depth equivalent to 100% ETC, L2: drip irrigation with DI at 75% ETc, and L3: drip irrigation with DI at 50% ETc. The DI treatments (L2 and L3) were implemented by forming stolons (60 DAS). As a result, L2 allows saving irrigation water of 3930 m³ ha−1 compared to L0 and 1164 m³ ha¯¹ compared to L1. It means a WPirri of 6.15 ± 0.35 kg m−3 allowing a commercial yield (CY: 27.15 ± 1.47 t ha¯¹) statistically similar to L1 (WPirri: 5.45 ± 0.34 kg m−3; CY: 30.14 ± 1.83 t ha¯¹) and higher than the traditional surface irrigation (WPirri: 2.63 ± 0.23 kg·m−3; CY: 21.62 ± 1.99 t ha¯¹). This water saving meant a net income of 3097.04 ± 435.52 USD ha¯¹ for L2, close to L1 (4421.12 ± 724.24 USD ha¯¹), and much higher than L0 (1664.50 ± 834.24 USD ha¯¹). The results suggest that using drip irrigation systems in terraced crops optimizes water savings, maintains yields and profitability, and could promote the modernization of terraces in rural environments.