Ridge-furrow plastic film mulching effectively mitigates water scarcity on the Loess Plateau, but its long-term sustainability is questionable. Strip intercropping offers a more water-efficient alternative to traditional monocropping. To investigate the dynamics of water-use and crop productivity under different strip intercropping systems, a three-year field experiment (2018–2020) was conducted. Four maize-based intercropping systems (maize-pea, M/P; maize-millet, M/G; maize-potato, M/S; maize-wheat, M/W) were compared with monocropping maize (MM). Crop yield, water consumption, water equivalent ratio (WER), land equivalent ratio (LER), and economic profit were analyzed. The soil water content was varied with season, soil layer, and cropping system. Maize-wheat intercropping (M/W) extracted water from below 140 cm depth. In contrast, monocropping maize under plastic film mulching showed a soil water deficit only in the 20–60 cm layer, and only at the end of the 2018 growing season. Regarding crop yield, the monocropping maize system (MM) achieved a yield of 9,732 kg ha -1 , while the maize-based intercropping systems (except M/S) showed yield reductions of 27.8–32.1% relative to MM. In contrast, LER and WER increased by 2.9–20.3% and 2.4–17.6%, respectively. Compared with monocropping maize, maize-potato intercropping (M/S) achieved higher crop yield and net income, whereas maize-pea intercropping (M/P) exhibited lower yield but greater water savings (ΔWU) and a higher input-output ratio (1.91). Despite a moderate input-output ratio, M/S showed superior performance in yield, net revenue, and water equivalent ratio (WER). These findings indicate that appropriate intercropping systems, especially M/S, can reduce soil water consumption while improving economic returns and land use efficiency. Based on a comprehensive assessment of crop productivity, economic benefit, water use efficiency, and land use efficiency, maize-potato intercropping is recommended as the most effective and sustainable system for rainfed farming on the Loess Plateau. • Strip intercropping can replace traditional maize monocropping under water-limited conditions. • Maize-potato intercropping is the recommended system in rainfed farming of the Loess Plateau. • Strip intercropping did not significantly increase soil water consumption. • Soil water depletion only occurred in a dry year with monocropping maize.
Zhang et al. (Fri,) studied this question.