Potassium rates on the cationic balance of an Oxisol and soybean nutritional status after 8 years of K deprivation

Author(s)

Firmano, Ruan Francisco ^[1] ; de Oliveira Junior, Adilson ^[2] ; de Castro, Cesar ^[2] ; Alleoni, Luis Reynaldo Ferracciu ^[1]

Affiliation

^[1] Univ Sao Paulo, Luiz de Queiroz Coll Agr ESALQ, Dept Soil Sci, Ave Padua Dias 11, BR-13418900 Piracicaba, SP - Brazil

^[2] Brazilian Agr Res Corp, Natl Soybean Ctr, Carlos Joao Strass Highway, BR-86001970 Londrina, Parana - Brazil

• Document type: Journal article
• Source: EXPERIMENTAL AGRICULTURE; v. 56, n. 2, p. 293-311, APR 2020.
• Web of Science Citations: 0

Abstract

Highly weathered soils from humid tropics naturally have low contents of available potassium (K) to plants. Under these conditions, the K deprivation can change the equilibrium among cations in the soil and the nutritional status of some crops as soybean (Glycine max(L.) Merrill). A field experiment related to K fertilisation, spring soybean and diverse species of fall/winter crops, such as wheat (Triticum aestivumL.), corn (Zea maysL.), sunflower (Helianthus annuusL.) or oat (Avena strigosaL.), has been carried out in Southern Brazil since 1983. The K deprivation for 8 years reduced soybean grain yield and the K contents in soil and plant tissues. K extractants, such as Mehlich-1 and ion exchange resins, had diverse sensitivities with the variation in the K exchangeable contents induced by K rates. The increased soil K content after K fertilisation reduced calcium (Ca) and magnesium (Mg) contents in index leaves and altered its contents in the soil extracted by 1 mol L-1KCl and ion exchange resins. Among the micronutrients, only B contents changed due to increased K rates, and had significant correlations with K and Ca contents in index leaves. The calculated Diagnosis and Recommendation Integrated System (DRIS) indices were compatible with soybean yield and K contents in soybean index leaves. (AU)

• FAPESP's process: 15/18952-3 - Residual effect of potassium fertilization on the forms of the nutrient in the soil
• Grantee: Ruan Francisco Firmano
• Support Opportunities: Scholarships in Brazil - Master