Field management practices drive ecosystem multifunctionality in a smallholder-dominated agricultural system.

• Soil biodiversity is positively related to agroecosystem multifunctionality. • Management practices are most important driving factors of multifunctionality. • High multifunctionality depends on high inputs of straw residues, organic and inorganic fertilizers. • Management practices are determined by smallholders' socioeconomic factors. Agroecosystems provide multiple goods and services that are important for human welfare. Despite the importance of field management practices for agroecosystem service delivery, the links of socioeconomic factors, management practices and ecosystem multifunctionality have rarely been explicitly evaluated in agroecosystems. Here we used a county-scale database with 100 farmer households and their farmlands, and analyzed the relative importance of management practices, soil abiotic environment and soil biota on multifunctionality under three distinct ('smallholder's viewpoint', 'sustainable soils' and 'equal weight') scenarios. Furthermore, we also analyzed the effect of smallholders' socioeconomic factors on management practices. Our results found that smallholders' high inputs of fertilizers and agrochemicals were associated with their high agricultural income and less farmland area, but total land area had a positive effect on straw incorporation. Total soil biota index was positively related to multifunctionality, however, management practices (fertilizer input, agrochemical input, organic fertilizer amount and straw incorporation) had stronger effect on multifunctionality than that of soil biota or the abiotic environment. Their strength varied with distinct scenarios. Our work suggests that increasing organic materials (organic fertilizers and crop residues) and decreasing agrochemicals are beneficial for maintaining or increasing ecosystem multifunctionality in smallholder-dominated agroecosystems. Moreover, improving management practices of smallholders needs to take into account the effects of their socioeconomic factors. [ABSTRACT FROM AUTHOR]