Evaluation of Different Shallow Groundwater Tables and Alfalfa Cultivars for Forage Yield and Nutritional Value in Coastal Saline Soil of North China

Abstract

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.

Distinct rhizosphere soil responses to nitrogen in relation to microbial biomass and community composition at initial flowering stages of alfalfa cultivars

“…This characteristic can affect the content of crude protein, biomass of alfalfa plants, and soil N content. The crude protein content of alfalfa is relatively high (over 20% in its stems and leaves; Elfaki and Abdelatti, 2016 ), with significant differences generally found among different cultivars ( Wang et al, 2022 ).…”

Effects of nitrogen application on winter wheat growth, water use, and yield under different shallow groundwater depths

“…Shallow groundwater exists in many regions ( Babajimopoulos et al., 2007 ), such as arid and semi-arid regions, the Yellow River basin in North China Plain, farmlands near irrigation districts, etc . ( Wang et al., 2009 ; Zhu et al., 2018 ; Lai et al., 2022 ; Wang et al., 2022 ). Soil capillary voids and crop roots absorb shallow groundwater to replenish crops and dissipate into the atmosphere, which affects crop growth and yield ( Liu et al., 2016 ; Soylu and Bras, 2022 ).…”