Affiliation:
1. College of Agricultural Sciences São Paulo State University (UNESP) Botucatu São Paulo Brazil
2. Center of Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Botucatu São Paulo Brazil
3. Faculty of Agricultural Sciences of Vale do Ribeira (FCAVR) São Paulo State University (UNESP) Registro São Paulo Brazil
Abstract
AbstractThe response of sweetpotato [Ipomoea batatas (L.) Lam.] to potassium (K) can vary based on soil K availability and the rate and timing of K application. This study evaluated the effects of K application rate and timing on leaf K concentration and yield attributes of sweetpotatoes grown in tropical sandy soils with different K availabilities. Treatments had three rates (60, 120, and 240 kg ha−1 K2O) and four timings (pl, the full rate at planting; pl‐1.3, 1/2 rate at planting plus 1/2 at 1.3 months after planting [MP]; pl‐3, 1/2 rate at planting plus 1/2 at 3 MP; pl‐1.3–3, 1/3 rate at planting plus 1/3 each at 1.3 and 3 MP), including a control (without K application). The benefits of K timings and application rates on sweetpotato yield were greater in K‐deficient soils with the maximum yield of sweetpotato (25.8–34.3 Mg ha−1) at the estimated rate of 153–179 kg ha−1 K2O in three application times. In soil with medium exchangeable K, the maximum total root yield (28.5–34.2 Mg ha−1) occurred at an optimum estimated rate of 113–122 kg ha−1 K2O. In soils with high exchangeable K, K application rates reduced the yield of roots or starch, and no K deficiency occurred in the unfertilized K treatments. To obtain high storage root and starch yields in sweetpotatoes grown in K‐deficient tropical sandy soils, there should be three K applications, and K application rates should be based on K levels already available in the soil.
Funder
Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Subject
Agronomy and Crop Science
Reference44 articles.
1. The Potassium Cycle and Its Relationship to Recommendation Development
2. Potassium nutrition of sweet potato;Byju G.;Advances in Horticultural Science,2005