Potassium sources impact on cassava plant productivity, quality and mineral composition

Abstract

In the mineral nutrition of plants, potassium is considered “the element of quality” of harvested products, and its lack or excess can cause decreased or loss of product quality. In this sense, the aim of the present study was to evaluate the productivity, root quality and mineral nutrient levels of the Pretinha cassava cultivar according to potassium sources and doses. Two sources (potassium chloride and potassium sulfate) and five K₂O doses (0, 30, 60, 90 and 120 kg of K₂O ha⁻¹) were tested, in a randomized block design, with five repetitions. After 11 months of sowing, five plants were manually harvested from the useful area of each plot and the number, diameter, firmness, root moisture and productivity were determined, in addition to the nutritional contents in different plant organs (leaf, stem and root and bark). Fertilization with potassium sulfate promotes higher root productivity, higher P and S levels in leaves and increased N and K levels in root barks. Potassium fertilization promotes a greater number of roots per plant, larger root diameter and greater external firmness, increased K content in plant organs and decreased Ca content in cassava leaves. The use of potassium chloride also increases Cl levels in cassava leaves.

Keywords:

• fertilization
• Manihot esculenta
• mineral nutrition
• potassium chloride
• potassium sulfate

Additional information

Funding

The authors wish to express their thanks and appreciation to State University of Northern Fluminense Darcy Ribeiro (UENF), Coordination of Improvement of Higher Education Personnel (CAPES), and Foundation Carlos Chagas Filho Research Support of the State of Rio de Janeiro (FAPERJ- <www.faperj.br>).