Nanosilica improves morphogenic and chemical parameters of Megathyrsus maximus grass under phosphorus deficiency and excess stress in different soils

Abstract

Abstract In cultivated soils with pastures in different regions of the world, phosphorus (P) imbalances are recurrent. In addition to P deficiency, the occurrence of areas with excess P in the soil has increased, with damage to pasture production. This reality requires the search for thoughtful strategies such as the use of silicon (Si), which is an element known to attenuate stress in plants. However, the action of Si on morphogenetic and chemical characteristics of grasses forages cultivated in different soils is not known. Therefore, this study aimed to evaluate the effects of P deficiency and excess on morphogenetic and chemical parameters, and on the digestibility of Zuri guinea grass cultivated in Oxisol and Entisol, and to analyze whether fertirrigation with nanosilica can mitigate the damage caused by these nutritional stresses. P deficiency decreased tiller number and grass protein content, and increased lignin content, while P excess increased the percentage of dead material and lignin, and decreased the leaf:stem ratio of plants, and both stresses decreased dry matter (DM) production. Fertirrigation with Si promoted better tillering and protein in deficient plants. In the excess of P, Si reduced tiller mortality and the lignin content of the plants, increasing the leaf:stem ratio and DM production, also increasing the production of plants with P sufficiency, without affecting the digestibility of the grass. Thus, the perspective is that the use of Si can improve the growth and chemical characteristics of forage grasses under P stress, and optimize production in nourished adapted plants, confident for more sustainable pasture production.