Impact of Environmental Factors on Seed Germination and Seedling Emergence of White Clover (Trifolium repens L.)

Lei Chu,Lingling Chen,Muthukumar Bagavathiannan,Suraj Sapkota,Patrick E Mccullough,David Jespersen,Yiping Gao,Jialin Yu

doi:10.3390/agronomy12010190

Abstract

White clover (Trifolium repens L.) is cultivated as a forage crop and planted in various landscapes for soil conservation. There are numerous reports of failed white clover stands each year. A good understanding of the seed germination biology of white clover in relation to environmental factors is essential to achieve successful stand establishment. A series of experiments were conducted to investigate the impacts of light, temperature, planting depth, drought, and salt stress on seed germination and the emergence of white clover. White clover is negatively photoblastic, and seed germination averaged 63 and 66% under light and complete dark conditions 4 weeks after planting (WAP), respectively. Temperature affected the seed germination speed and rate. At 1 WAP, seeds incubated at 15 to 25 °C demonstrated a significantly higher germination rate than the low temperatures at 5 and 10 °C; however, the germination rate did not differ among the temperature treatments at 4 WAP. The results suggest that white clover germination decreases with increasing sowing depths, and the seeds should be sown on the soil surface or shallowly buried at a depth ≤1 cm to achieve an optimal emergence. White clover seeds exhibited high sensitivity to drought and salinity stress. The osmotic potential and NaCl concentration required to inhibit 50% seed germination were −0.19 MPa and 62.4 mM, respectively. Overall, these findings provide quantifiable explanations for inconsistent establishment observed in field conditions. The results obtained in this research can be used to develop effective planting strategies and support the successful establishment of white clover stands.

Highlights

White clover (Trifolium repens L.), a plant species in the Fabaceae family, typically grows as a creeping, mulch-branched perennial [1]
White clover is often included in perennial ryegrass (Lolium perenne L.) pastures [6,7]
The objective of this research was to examine the effects of light, temperature, seeding depth, drought, and salinity on white clover seed germination and seedling emergence

Summary

Introduction

White clover (Trifolium repens L.), a plant species in the Fabaceae family, typically grows as a creeping, mulch-branched perennial [1]. Due to its high crude protein content, white clover is widely cultivated as a legume forage crop [3,4,5]. White clover is often included in perennial ryegrass (Lolium perenne L.) pastures [6,7]. This mixed system provides highquality livestock feed [5] while simultaneously improving soil fertility since legumes can fix atmospheric nitrogen with symbiotic bacteria [8]. In China, white clover is often cultivated alone as a substitute for low-maintenance turfgrasses [11] or intercropped into an orchard or vineyard as a cover crop for the purpose of soil conservation [12,13]

Objectives

Methods

Results