Soil Nutrient Uptake by Non-Legume Plants

Plants require a variety of nutrients to grow and thrive, two of which are phosphorus and sulphur. Let's delve into the role these elements play in plant life.

Phosphorus, an essential nutrient that constitutes about 0.2% of a plant's dry weight, is divided into three forms in soil: plant-available phosphorus (in soil solution), sorbed phosphorus (attached to clay surfaces and metal oxides), and mineral phosphorus (primary and secondary phosphate minerals). The availability of phosphorus to plants is influenced by various processes such as mineralization, immobilization, adsorption, desorption, weathering, precipitation, and dissolution.

Phosphorus deficiency can reduce plant growth and development and potentially limit crop yield. Non-leguminous plants can obtain phosphorus from the soil, but factors such as organic matter, clay content, soil mineralogy, soil pH, temperature, and moisture can influence its availability.

Sulphur, another crucial plant nutrient, plays a vital role in amino acid formation, photosynthesis, and biological nitrogen fixation. Sulphur-deficient plants may exhibit short and/or spindly stems and yellowing of the young (top) leaves. Sulphur enters soils primarily through organic matter. To address sulphur deficiencies, farmers can apply sulphur fertiliser in three main types: sulphate-sulphur, elemental sulphur, and thiosulphate.

Hydrogen, while considered safe for use on plants, should be handled with caution due to its highly flammable nature. Hydrogen has been shown to have a range of beneficial effects on plants, including improving seed germination rates, regulating flowering time, and enhancing resistance to abiotic stressors. However, the exact mechanisms of how hydrogen acts on plants are not yet fully understood.

Plants that form symbiotic relationships with certain fungi to acquire nitrogen from the soil are mainly those engaging in mycorrhizal associations. However, it is important to note that nitrogen acquisition is primarily linked to symbiosis with nitrogen-fixing bacteria such as Rhizobia in legumes, not fungi.

Phosphorus deficiency and sulphur deficiencies can have detrimental effects on plant growth and yield. Understanding the role of these elements and how they interact with plants can help farmers and gardeners optimise their plant care practices.