Characterizing phosphorus losses and optimizing agricultural practices for phosphorus sustainability on the Qinghai–Tibetan plateau

Abstract

Phosphorus (P) losses on the Qinghai–Tibetan Plateau (QTP) have increased prominently over the past few decades, adversely affecting the P sustainability of alpine ecosystems. However, the assessment of current P losses and the optimization of agricultural practices for P sustainability on the QTP remain inadequately explored. To bridge these knowledge gaps, we developed an integrated framework incorporating multivariate data, life-cycle assessment, safe and just operating space, and a linear optimization model. Our results reveal that the total P losses on the QTP amount to 15.22 kt P year⁻¹, with livestock systems contributing more than twice as much as crop systems. Furthermore, about 10 % and 16 % of the areas exceeded the safe boundaries of P losses for loose and strict objectives, respectively. The optimization model demonstrates that reorienting the distributions of crops and livestock could substantially reduce P losses, with a maximum reduction potential of 67.42 % while mitigating 69.91 %–82.61 % of safe boundary transgressions for P losses to surface water. Our findings underscore the challenges and opportunities in achieving P sustainability on the QTP to meet the growing human food demands while safeguarding alpine ecosystems.