Review on the fully mulched ridge-furrow system for sustainable maize production on the semi-arid Loess Plateau

The fully mulched ridge-furrow (FMRF) system has been widely used on the semi-arid Loess Plateau of China due to its high maize (Zea mays L.) productivity and rainfall use efficiency. However, high outputs under this system led to a depletion of soil moisture and soil nutrients, which reduces its sustainability in the long run. Therefore, it is necessary to optimize the system for the sustainable development of agriculture. The development, yield-increasing mechanisms, negative impacts, optimization, and their relations in the FMRF system are reviewed in this paper. We suggest using grain and forage maize varieties instead of regular maize; mulching plastic film in autumn or leaving the mulch after maize harvesting until the next spring, and then removing the old film and mulching new film; combining reduced/no-tillage with straw return; utilizing crop rotation or intercropping with winter canola (Brassica campestris L.), millet (Setaria italica), or oilseed flax (Linum usitatissimum L.); reducing nitrogen fertilizer and partially replacing chemical fertilizer with organic fertilizer; using biodegradable or weather-resistant film; and implementing mechanized production. These integrations help to establish an environmentally friendly, high quality, and sustainable agricultural system, promote high -quality development of dryland farming, and create new opportunities for agricultural development in the semi-arid Loess Plateau.