Exploring alternative crop rotations to continuous winter wheat for agricultural intensification in the US central Great Plains

CONTEXT: Low productivity, yield stagnation, and reduction of water use, altogether with increased susceptibility to climate variability represent a challenge for agricultural producers in the United States (US) central Great Plains. In this context, a more holistic assessment of the cropping systems should be considered as a critical aspect for developing more sustainable rainfed agricultural systems in this region. OBJECTIVE: The objectives of this study were to: i) quantify the fallow precipitation storage efficiency for a continuous winter wheat rotation (traditional rotation), ii) analyze and compare glucose-equivalent yields and economic results for different cropping sequences, and iii) determine efficiency components of the rotation for components such as precipitation use efficiency (PUE) and nitrogen (N) partial factor productivity (PFPN) for different cropping sequences and N management. METHODS: A three-year field experiment (2019-2022) was conducted near Manhattan, Kansas (US), under rainfed conditions. Treatments included eleven crop rotations, combining forage and grain purpose crops, and two N management, standard and progressive. An economic analysis based on the yield data combined with historical budgets was developed to compare income, expenses, and economic margins of different cropping systems. RESULTS AND CONCLUSIONS: No -till summer fallow represented low (<20%) precipitation storage efficiency in the continuous winter wheat cropping system. In terms of cumulative dry matter and glucose -equivalent yields, greater overall productivity was feasible for more intensified systems and when forage crops were included in the crop sequence (e.g., -15 vs. -30 Mg glucose equivalent (GE) ha(-1), for wheat monoculture and forage purpose only rotations, respectively). However, cropping sequences with high frequency of forages had negative economic margins (US$ -1113 to US$ -626 ha(-1)), while winter wheat combined with grain double crop rotation attained the highest positive economic returns (US$ 571 ha(-1)). Finally, progressive N -management increased PFPN relative to the standard management (63.5 vs. 54.2 kg GE kg N-1, respectively) while maintaining PUE for several intensified crop rotations. SIGNIFICANCE: Expanding the adoption of more intensified and diversified cropping systems could increase resource capture and use efficiency and productivity in the dominant continuous winter wheat systems in the US central Great Plains.