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

Shichao Wang,Xiaojing Liu,Asif Ameen,Lipu Han,Dong Fang,Kai Guo,Xiaolin Li

doi:10.3390/life12020217

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.

Highlights

Soil salinization and alkalization have become more serious in numerous coastal regions throughout the world [1]
In order to more fully understand the variation of forage yield, nutritional value, and turn-green ratio in alfalfa, the objectives of this study were to the following: (1) compare the biomass production and forage nutritional value of alfalfa cultivars planted at different shallow groundwater depths; (2) reveal the effects of different shallow groundwater depths and cultivars on the turn-green ratio of alfalfa in the second year after planting
To maintain a higher alfalfa yield, our results suggest that Magnum551 and Phabulous could prove the best cultivars to be planted in this saline region of North China at a shallow groundwater depth of 100 cm (Figure 3)

Summary

Introduction

Soil salinization and alkalization have become more serious in numerous coastal regions throughout the world [1]. Saline–alkali soil is unfavorable for agricultural productivity, but is unfavorable for water storage and soil nutrient availability, inevitably leading to drought [2]. Both drought and salt–alkali stress adversely influence crop growth via restricted water uptake and the presence of excessive salt [3,4]. The underlying saline groundwater in this area provides abundant water resources for agricultural production [10] and has a large potential for exploitation and use. The use of shallow groundwater has become an important measure to relieve agricultural freshwater scarcity [11]. Agricultural water demand will have to rely on shallow saline water to meet the crop water requirements in the future

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Discussion

Conclusion