Silicon-The Most Underappreciated Element in Vegetable Production: A Comprehensive Review

Abstract

Silicon (Si) is the second most abundant element in the Earth's crust yet remains conspicuously absent from mainstream fertiliser programmes and nutrient management guidelines for vegetable crops. Although Si does not satisfy the classical criteria of essentiality for higher plants, an extensive and rapidly growing body of literature confirms that its supply confers remarkable benefits on plant growth, stress tolerance, disease resistance and produce quality. Vegetable crops represent a diverse and nutritionally indispensable component of global food systems, yet they are among the plant categories most frequently neglected especially when Si is considered during nutrition, partly because many vegetable species are classified as low Si accumulators. This review synthesises current knowledge on the geochemistry of Si in soils, the molecular biology of Si uptake and transport, and the multifaceted agronomic roles of Si specifically in vegetable production systems. Evidence from controlled experiments and field studies demonstrates that Si supplementation enhances vegetative growth, alleviates drought, salinity, heavy metal, and temperature stresses, suppresses soil-borne and foliar diseases, deters insect herbivory, and improves post-harvest shelf life and nutritional quality of vegetable produce. The review further examines the range of Si fertiliser sources and application modalities suitable for vegetable production, and situates Si management within broader frameworks of sustainable and low-input horticulture. Critical gaps in understanding — including the scarcity of field-scale trials for specific vegetable species, the absence of calibrated soil and tissue Si tests for horticultural crops, and limited mechanistic insight for dicotyledonous vegetables — are identified and discussed. The evidence collectively argues that Si deserves recognition not merely as a non-essential beneficial element but as a practically indispensable component of modern vegetable nutrition management.