Background Bermudagrass (Cynodon dactylon) has a long history as an excellent forage grass, and salt stress will inhibit its growth and development. In order to minimize the damage, it is necessary to continuously develop innovative technologies and management strategies. Results This study evaluated the salt tolerance of new Bermudagrass strains 'FB2019R101' and 'FB2019R105' compared to commercial varieties 'Wrangler' and 'A12359' under simulated soil salinity conditions through seawater irrigation. Through correlation analysis of growth, physiological, and nutritional indicators, and principal component analysis, core indicators and weights for salt tolerance evaluation were identified. The salt-tolerant varieties were 'FB2019R101' and 'FB2019R105'. Under salinity stress, the plants of Bermudagrass varieties with salt tolerance suffered less damage as a whole, which could better regulate the osmotic balance inside and outside cells, accumulate more nutrients and have stronger ability to resist salt damage. The expression level of salt-tolerant variety CdCINV1, CdSPS1, CdSUS5, and CdSWEET6 was up-regulated under salt stress. CdCINV1, CdSPS1, CdSUS5 can promote the transformation of sucrose into glucose and fructose in Bermudagrass under salt stress, and CdSWEET6 can promote the accumulation of fructose. Conclusions 'FB2019R101' and 'FB2019R105' exhibited higher salt tolerance, with minimal impact on their biomass, physiological, and nutritional indicators under salt stress. The comprehensive evaluation revealed a salt tolerance ranking of 'FB2019R105' > 'FB2019R101' > 'Wrangler' > 'A12359'. This study provides significant reference for the bioremediation of coastal saline soils and promotes research on the application of Bermudagrass under salt stress conditions. CdCINV1, CdSPS1, CdSUS5, and CdSWEET6 can improve the salt tolerance of plants by regulating the changes of carbohydrates.

Amaranth (Amaranthus hypochondriacus L.) is a potential forage crop with a high yield and crude protein (CP) content; however, establishment methods need to improve for the crop to be less sensitive to typhoons. Optimal establishment, cultivation, and utilization in amaranth were examined in a variety of seasons and methods of establishment in 2021-2023. Four methods were examined: (1) direct seeding in rows, (2) direct seeding in spots, (3) soil seed balls, and (4) transplant pretreatment methods under a randomized blocked design (n = 3). Sowings every month from April to August were applied only in 2021, while establishments in April, May, and August with both pretreatment methods were applied in 2022 and 2023. The establishment in August successfully escaped damage from typhoons. The direct seeding of either rows or spots showed marginal success in establishment compared to stable establishment in pretreatment methods. In 2022 and 2023, the highest yield and CP content were achieved in soil seed balls plots in April and in both pretreated plots sown in August, respectively. The quality of silage fermentation showed a high pH, ranging from 4.52 to 6.39, due to the high CP content in 7.59-18.36% dry matter (DM). Sowing in April or August established with soil seed balls can avoid typhoon damage to have stable forage yields and can be processed with a favorable quality of amaranth silage in the region.

Agricultural practices enhancing soil organic carbon (SOC) show potential to buffer negative effects of climate change on forage grass performance. We tested this by subjecting five forage grass varieties differing in fodder quality and drought/flooding resistance to increased persistence in summer precipitation regimes (PR) across sandy and sandy-loam soils from either permanent (high SOC) or temporary grasslands (low SOC) in adjacent parcels. Over the course of two consecutive summers, monoculture mesocosms were subjected to rainy/dry weather alternation either every 3 days or every 30 days, whilst keeping total precipitation equal. Increased PR persistence induced species-specific drought damage and productivity declines. Soils from permanent grasslands with elevated SOC buffered plant quality, but buffering effects of SOC on drought damage, nutrient availability and yield differed between texture classes. In the more persistent PR, Festuca arundinacea FERMINA was the most productive species but had the lowest quality under both ample water supply and mild soil drought, whilst under the most intense soil droughts, Festulolium FESTILO maintained the highest yields. The hybrid Lolium x boucheanum kunth MELCOMBI had intermediate productivity and both Lolium perenne varieties showed the lowest yields under soil drought, but the highest forage quality (especially the tetraploid variety MELFORCE). Performance varied with plant maturity stage and across seasons/years and was driven by altered water and nutrient availability and related nitrogen nutrition among species during drought and upon rewetting. Moreover, whilst permanent grassland soils showed the most consistent positive effects on plant performance, their available water capacity also declined under increased PR persistence. We conclude that permanent grassland soils with historically elevated SOC likely buffer negative effects of increasing summer weather persistence on forage grass performance, but may also be more sensitive to degradation under climate change.