Silicon Promotes Agronomic Performance in Brassica napus Cultivated under Field Conditions with Two Nitrogen Fertilizer Inputs

Philippe Laîné,Cylia Haddad,Jean-Claude Yvin,Mustapha Arkoun,Philippe Etienne

doi:10.3390/plants8050137

Abstract

To limit the environmental pollution associated with intensive nitrogen (N) fertilizer usage, alternative cultural practices must be considered for crops requiring high N inputs such as rapeseed. In this context, the effects of silicon (Si) supply on the agronomic performance of rapeseed cultivated under field conditions with two N fertilizer levels (60 and 160 kg ha−1) were studied. Results showed that Si supplied in the form of silicic acid (12 kg ha−1) has no effect on the agronomic performance of plants cultivated with the lower N input. In contrast, in plants fertilized with 160 kg N ha−1, Si supply promotes the preservation of green leaves (until the flowering stage) and at harvest stage, increases biomass, yield, and seed micronutrient concentrations (especially cobalt and iron). The agronomic indexes show that the increase in seed yield is related to a better uptake of N from the soil by Si-treated plants, but is not an improvement in N mobilization towards the seeds. This study showed that Si supply combined with high N inputs (160 kg ha−1) improves usage of N fertilizer and yield. The possibility that a Si supply could allow for a reduction in N input without altering the yield of rapeseed is discussed.

Highlights

Silicon (Si) is the second most abundant element in the soil after oxygen and comprises about 28%of the Earth’s crust [1,2]
Silicic acid is taken up by plants via aquaporins belonging to the Nodulin-26-like intrinsic proteins 2 (NIP2) group with a G-S-G-R SF pore (NIP-III aquaporins) known as the Si influx transporter (Lsi1) [5,6].Vascular plant species have different abilities to take up and accumulate Si, leading to classification into three groups according to the Si concentration: “strong accumulators”, such as rice, with a Si content reaching 15% of dry weight (DW), “intermediate accumulators”, such as rye, oats, or wheat, with a Si content comprising 1%–3% of DW, and “weak Si accumulators” like rapeseed with a Si content of less than 0.1% of DW [7,8,9,10]
Si ha−1 ) with the lower nitrogen input (60 kg N ha−1 ) had no significant effect on the growth, yield, or seed quality of rapeseed cultivated under field conditions (Figures 2 and 3A; Table 2)

Summary

Introduction

Silicon (Si) is the second most abundant element in the soil after oxygen and comprises about 28%of the Earth’s crust [1,2]. Silicic acid (Si(OH)4 ), the soluble form of silicon available for plants is very scarce in most soils Silicic acid is taken up by plants via aquaporins belonging to the Nodulin-26-like intrinsic proteins 2 (NIP2) group with a G-S-G-R SF pore (NIP-III aquaporins) known as the Si influx transporter (Lsi1) [5,6].Vascular plant species have different abilities to take up and accumulate Si, leading to classification into three groups according to the Si concentration: “strong accumulators”, such as rice, with a Si content reaching 15% of dry weight (DW), “intermediate accumulators”, such as rye, oats, or wheat, with a Si content comprising 1%–3% of DW, and “weak Si accumulators” like rapeseed with a Si content of less than 0.1% of DW [7,8,9,10]. Si application reduces the severity of fungal diseases such as powdery mildew in barley [12] and other

Objectives

Methods

Conclusion