The regulation and management of ecosystem services are fundamental for sustainable development in mountain areas. Although no obvious vertical band spectrum exists in Taihang Mountain region, vertical differentiation of ecological characteristics in the region is obvious. The ecosystem characteristics of vertical differentiation were analyzed using 4 typical ecological indices (land use, temperature, net primary productivity, and water yield). The ecosystem service functional pattern was determined based on analysis of the ecosystem services value per unit area. The 2 ecosystem critical zones of vertical differentiation (500–600 m and 1400–1500 m) were determined. The mountain area was divided into 3 ecological zones—sub-alpine zone (>1500 m), mid-mountain zone (600–1400 m) and hilly zone (<500 m). The ecosystem services functional pattern was as follows: provisioning services was the main ecosystem services function in the hilly zone, 4 ecosystem service functions were equally important in the mid-mountain zone, regulating, supporting and cultural services were the main ecosystem service functions in the sub-alpine zone. The model of ecosystem service regulation and management in 3 ecological zones was built based on the functional patterns to promote sustainable development.

Introduction: Alfalfa (Medicago sativa L.) has significant feed value and ecological improvement function of marginal land. The difference in the maturity period of seeds in the same lots may be a mechanism of environmental adaptation. Seed color is a morphological trait associated with seed maturity. A clear understanding of the relationship between the seed color and seed stress resistance is helpful for seed selection for marginal land.Methods: This study evaluated the seed germination parameters (germinability and final germination percentage) and subsequent seedling growth (sprout height, root length, fresh and dry weight) of alfalfa under different salt stress, measured the electrical conductivity, water uptake, seed coat thickness, and endogenous hormone content in alfalfa seeds with different colors (green, yellow and brown).Results: The results showed that seed color significantly influenced the seed germination and seedling growth. The germination parameters and seedling performance of brown seeds were significantly lower than that of green and yellow seeds under different salt stress. The germination parameters and seedling growth of brown seed declined most obviously with the aggravation of salt stress. The results suggested that brown seeds were less resistant to salt stress. Seed color had a significant effect on electrical conductivity, and it indicated that the yellow seeds had higher vigor. The seed coat thickness of various colors did not differ significantly. The seed water uptake rate and hormone content (IAA, GA3, ABA) in brown seeds were higher than that in green and yellow seeds, while the (IAA+GA3)/ ABA in yellow seeds were higher than green and brown seeds. The alterations in seed germination and seedling performance among seed colors are likely due to the combination effect of the content and balance between IAA+GA3 and ABA.Discussion: These results could improve the understanding of stress adaptation mechanisms of alfalfa and provide a theoretical basis for screening alfalfa seeds with high stress resistance.

Alfalfa (Medicago sativa L.) production is affected by many factors, including management practices, soil conditions, and the environmental elements of the target area. Varietal differences, in terms of agronomic performance and forage yield, among 50 alfalfa cultivars under six harvest systems following regrowth were evaluated during the growing season of 2019–2020 under non-irrigated rainfed conditions in a coastal saline-alkali soil region of North China. Days to harvesting, plant height, canopy area, growth rate, and forage yield were assessed to rank the cultivars. Furthermore, the key factor influencing the regrowth of the second year after over-wintering was identified based on the growth status before over-wintering by using the Boston Matrix method. Results showed significant (p < 0.05) differences among cultivars and harvests regarding plant height, canopy area, and forage yield. Alfalfa forage yield ranged between 24.2 t ha⁻¹ yr⁻¹ and 32.7 t ha⁻¹ yr⁻¹. The highest forage yield was obtained in cultivar Guochan No.1, and was lowest in cultivar Magnum 601. Forage yield reached the greatest values for the first harvest, and then decreased gradually and changed stably. The forage yield of the third, fourth, fifth, and sixth harvest ranged from 3.4 t ha⁻¹ to 4.3 t ha⁻¹ (averaged across 50 cultivars), which represented 10.8% to 15.2% of the annual total forage production. We also observed that forage yield correlated strongly, but negatively, with the growth rate. According to subordinate function value analysis, Womu No.1, WL440HQ, Weston, Surprise, and WL354HQ proved optimum cultivars for general cultivation in this coastal area. In future, development of alfalfa cultivars with improved regrowth and tolerance to heavy saline-alkali soil and early spring drought would be necessary to increase forage yield under rainfed conditions in coastal saline-alkali areas of North China.

Freshwater shortage and soil salinization are the major constraints for alfalfa (Medicago sativa L.) growth in coastal salt–alkali soil of North China. In this study, we analyzed the effects of shallow groundwater tables and alfalfa cultivars on forage yield and nutritional value. A field simulation experiment was conducted during the growing season of 2019–2021 with three groundwater depths (80, 100, and 120 cm) and five alfalfa cultivars (Magnum 551, Phabulous, Zhongmu No. 1, Zhongmu No. 3, and WL525HQ) under subsurface pipe systems. Alfalfa forage was harvested six times in total during the growing season. Results revealed significant variation among alfalfa cultivars for forage yield at each shallow groundwater depth. The greatest forage yield was recorded in cultivar Phabulous (32.2 and 35.9 t ha⁻¹ in 2020 and 2021) when planted at 100 cm shallow groundwater depth. Forage yield during the first harvest was 24.6–25.7%, exhibiting the highest ratio of the total annual yield. The effects of shallow groundwater depth, cultivar, and their interaction were significant (p < 0.01) on the turn-green ratio of alfalfa. Cultivar Zhongmu No. 1 had the highest turn-green ratio at the 100 cm groundwater depth, while cultivar WL525HQ showed the lowest turn-green ratio at each groundwater depth. Moreover, crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content were also significantly affected by shallow groundwater depth, cultivars, and their interaction at different harvests. Cultivars Magnum551, Zhongmu No. 1, Zhongmu No. 3, and Phabulous furnished the highest CP, while cultivar WL525HQ performed the poorest in terms of CP in this study. These results propose that planting the cultivar Phabulous at a groundwater depth of 100 cm could be a suitable agronomic practice for alfalfa forage production in the coastal salt–alkali area of North China.