Soil biodiversity and crop diversification are vital components of healthy soils and agricultural sustainability

The fast-growing world population exerts great pressure on the land to produce enough nutritious food. It is projectedthat global population will be 50% greater than at present by 2050 and the demand for global grain will havedoubled[1]. The pressure further intensifies with the stresses resulting from climate change, associated extremeweather[2], and expansion of urbanization. Humanity has already transgressed three of the nine interlinked planetaryboundaries, and agriculture is the major driving force behind this development[3]. The agricultural system must betransformed to simultaneously provide global food security and environmental integrity[4]. To address thesechallenges, sustainability in agriculture must be enhanced[3,5]. This is particularly true for rapidly developingcountries such as China. While intensive, industrial agriculture achieved enormous successes, such as feeding 20%of the global population by producing 25% of the world’s grain with less than 10% of world arable land, theseachievements came at the expense of low resource use efficiency and environmental problems such as airpollution[6], water pollution[7], and soil acidification[8]. Agriculture in China is facing unprecedented challenges.In 2017, the Chinese government proposed Agriculture Green Development (AGD) as“a national strategy ofsustainable development; pursuing green development”, in line with the call of the United Nations SustainableDevelopment Goals AGD, emphasizing the development of a more sustainable agriculture and a greener eco-environment and food industry. To realize the goals of AGD and to alleviate the deleterious effects of intensiveagriculture, excessive use of external resource inputs, e.g., mineral fertilizers and agrochemicals, must be reducedand internal regulatory ecosystem processes must be promoted (Fig. 1). Ecological intensification is the strategy ofchoice to achieve these goals, as it focuses on managing and promoting ecosystem service-providing organismsand processes that make a quantifiable direct or indirect contribution to agricultural production[9]. The benefits ofecologically intensifying agriculture are achieved through greater reliance on biodiversity andecosystemservices[10], including the management of soils and their biota[11]. The regulation of internal soil ecosystem processhas been compared to the operation and relevance of the gut microbiome in the human body[12]. Soils providehabitat to a wealth and diversity of organisms, including microbes, invertebrates and vertebrates, adding up toseveral thousands of species per cubic meter of soil making it one of the most biodiverse habitats on earth[13]. Plantroots, the associated microbiome, and soil microbiota interact in a multitude of ways and collectively perform multiplefunctions, such as the enhancement of nutrient availability, prevention of pests and diseases, carbon storage, andimprovement of soil structure and water holding capacity[14]. Soil health, by definition, is the capacity of a living soil tofunction, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain orenhance water and air quality, and promote plant and animal health[15]. ..