Plant senescence is a critical life history process accompanied by chlorophyll degradation and has large implications for nutrient resorption and carbohydrate storage. Although photoperiod governs much of seasonal leaf senescence in many plant species, temperature has also been shown to modulate this process. Therefore, we hypothesized that climate warming would significantly impact the length of the plant growing season and ultimate productivity. To test this assumption, we measured the effects of simulated autumn climate warming paradigms on four native herbaceous species that represent distinct life forms of alpine meadow plants on the Tibetan Plateau. Conditions were simulated in open-top chambers (OTCs) and the effects on the degradation of chlorophyll, nitrogen (N) concentration in leaves and culms, total non-structural carbohydrate (TNC) in roots, growth and phenology were assessed during one year following treatment. The results showed that climate warming in autumn changed the senescence process only for perennials by slowing chlorophyll degradation at the beginning of senescence and accelerating it in the following phases. Warming also increased root TNC storage as a result of higher N concentrations retained in leaves; however, this effect was species dependent and did not alter the growing and flowering phenology in the following seasons. Our results indicated that autumn warming increases carbohydrate accumulation, not only by enhancing activities of photosynthetic enzymes (a mechanism proposed in previous studies), but also by affecting chlorophyll degradation and preferential allocation of resources to different plant compartments. The different responses to warming can be explained by inherently different growth and phenology patterns observed among the studied species. The results implied that warming leads to changes in the competitive balance among life forms, an effect that can subsequently shift vegetation distribution and species composition in communities.

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The objective of the present study was to evaluate the silage quality of forage soybean‐corn stover silage in the south of China. Forage soybean were combined manually with corn stover by ratios of R1 (25:75), R2 (50:50) and R3 (75:25) in fresh weight (FM) and ensiled in bag silos for 60 days at room temperature (20–25°C). All silages were treated without (control) or with lactic acid bacteria (LAB) inoculant (G, Lactobacillus plantarum and Lactobacillus buchneri, 105 cfu/g, of FM), cellulase (C, 0.02% of FM) and C + G. R1 silage had appropriate V‐score value with high lactic acid content and low pH value and ammonia‐N (NH3‐N) content, undetectable levels of propionic acid (PA) and butyric acid (BA). C and C + G reduced undesirable microorganisms of aerobic bacteria, yeasts and molds, resulting in improved nutritive value of R2 silage, as indicated by lower neutral detergent fiber and acid detergent fiber contents, and higher crude protein content, in vitro ruminal dry matter digestibility, gross energy and metabolizable energy values as compared to the control. Additives did not improve the quality of R3 silage with high pH value and NH3‐N content, BA and PA contents and undesirable microorganism counts. These results confirmed that high‐quality silage produced from mixtures (25:75) of forage soybean and corn stover in the south of China; additives (especially for C + G) could enhance the silage quality of forage soybean‐corn stover (50:50); and high proportion (>75%) of forage soybean was difficult to ensile.

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