Small soil wetted proportion and emitter flow rate of drip irrigation enhance potato yield by improving soil water and aeration in the sandy loam in arid Northwest China

Abstract

Creating an ideal soil microclimate through appropriate drip irrigation management practices is crucial for enhancing potato production. Field experiments were conducted during 2021 and 2022 in Wuwei, Gansu Province, Northwest China, with two soil wetted proportion levels (P1: 35 %, and P2: 55 %) and three emitter flow rates (F1: 1.3 L/h, F2: 2.0 L/h, and F3: 3.0 L/h). Results showed that for the same soil wetted proportion, soil water content was reduced in the 0–20 cm soil layer and increased in the 20–40 cm for F1 compared to F2 and F3, with no differences in the 40–60 cm depth. During the tuber initiation and bulking stages, the soil wetted proportion P1 increased soil oxygen saturation by 2.8 % and 0.7 % and reduced CO2 concentration by 26.7 % and 19.2 % in 2021 and 2022, respectively, compared to P2 in the 20–40 cm soil layer. The emitter flow rate F1 exhibited significantly greater soil oxygen (0.7–4.6 %) and lower CO2 concentration (16–46 %) than F2 and F3 in the 0–20 cm. Soil oxygen was significantly higher (0.5–2.1 %) and CO2 concentration was significantly lower (10–39 %) in the 20–40 cm in F1 than in F3. In the 0–40 cm soil layer, both the highest soil oxygen concentration and lowest CO2 concentration were observed for the P1F1 combination. The soil wetted proportion P1 increased average yield by 5.6 % in 2021 and 11.9 % in 2022 compared to P2, while F2 and F3 reduced yield by 2.4 % and 4.6 % in 2021, 4.1 % and 13.8 % in 2022 compared to F1. The soil wetted proportion P2 promoted source growth compared to P1 but limited sink expansion. Source capacity, sink growth, and average tuber growth rates decreased from F1 to F3. Overall, the 35 % soil wetted proportion and 1.3 L/h emitter flow rate are recommended for potato cultivation in sandy loam. This study clarified the importance of coordinating soil water and aeration by drip irrigation management to improve potato tuber production.