Dry-matter output contrasts and reference emergy performance in grassland restoration: A site-level assessment of selected no-tillage reseeding projects in northern Xinjiang, China.

Grassland restoration performance depends not only on engineering interventions but also on local reference conditions and resource-use patterns. We assessed 14 no-tillage reseeding projects in northern Xinjiang (3 meadow, 7 steppe, 4 desert) by integrating four renewable environmental inputs, five budget categories, and concurrent reference- and engineering-area dry-matter and vegetation surveys in a site-level reference emergy framework. Meadow sites had the highest median reference-area output (8.391 × 1010 sej m-2), reference emergy yield ratio (EYRref = 3.796), reference emergy sustainability index (ESIref = 2.274), and marginal reference return (MEYref = 1.566), and the lowest environmental loading ratio (ELR = 1.359). Steppe sites had the largest median relative output contrast (ΔY = 245.7%). None of the nine grassland-type comparisons was significant after Holm adjustment, so these patterns describe the sampled sites. Engineering-minus-reference medians were +38.6 percentage points for total cover, +0.93 operational taxa per quadrat for richness, and +0.182 for Shannon diversity; all were significant after Holm adjustment, but none of six prespecified associations with ΔY or ESIref was significant. MEYref was positively associated with ESIref (ρ = 0.855, Holm-adjusted P = 0.00045), whereas ΔY-ESIref was positive but uncertain (ρ = 0.376, P = 0.187); formula-preserving diagnostics showed compatibility with shared calculation components. Overall, meadow sites combined higher output and marginal return with lower purchased-input loading, steppe sites showed the largest output contrast without a corresponding rise in ESIref, and desert sites had lower median performance. Under fixed-output assumptions, seed had the greatest influence on ESIref followed by labor. These findings support joint consideration of local reference conditions, vegetation responses, and input efficiency in differentiated restoration review.