Data/hora: 25/06/2024 06:20:29

Biblioteca(s): 	Embrapa Pecuária Sudeste.	
Data corrente: 	01/06/2018	
Data da última atualização: 	04/01/2019	
Autoria: 	BERNARDI, A. C. de C.; SOUZA, G. B. de; VALE, F.	
Afiliação: 	ALBERTO CARLOS DE CAMPOS BERNARDI, CPPSE; GILBERTO BATISTA DE SOUZA, CPPSE; Fábio Vale, International Potash Institute.	
Título: 	Polyhalite compared to KCl and gypsum in alfalfa fertilization.	
Ano de publicação: 	2018	
Fonte/Imprenta: 	Electronic International Fertilizer Correspondent (e-ifc) n.52, march, 2018.	
Páginas: 	7 p.	
Idioma: 	Inglês	
Conteúdo: 	Poor acidic soils significantly challenge potassium (K) availability for crop production in Brazil. Therefore, huge amounts of K fertilizers, mostly KCl, are applied yearly. Nevertheless, KCl agronomic efficiency in those soil is often insufficient, hence alternative K donors are sought. In the present study, polyhalite, a natural mineral with potential as a multi-nutrient (11.7, 19, 3.6, and 12.1% of K, sulfur (S), magnesium (Mg), and calcium (Ca), respectively) fertilizer, was examined in a pot-grown (local topsoil) alfalfa (Medicago sativa L.) experiment vs. KCl together with gypsum. Four K application rates (equivalent to 0, 50, 100, and 200 kg K2 O ha?1) were tested with seven fertilizer combinations: KCl; KCl + gypsum1; KCl + gypsum2; polyhalite + KCl (1:7); polyhalite + KCl (1:1); polyhalite + KCl (7:1); and polyhalite. The results of seven successive harvests indicated that K application was essential to obtain considerable plant biomass in a K-rate dependent pattern. Polyhalite application, in combination with KCl or exclusively, gave rise to significantly higher biomass yields than KCl application, with or without gypsum. Polyhalite significantly enhanced K, S, Ca, and Mg uptake, particularly when applied alone at the highest dose. Indications of K-Mg or Cl-S competition seen under KCl application diminished under polyhalite. In conclusion, under the terms of a pot-grown experiment, polyhalite appeared as a promising alternative among K fertilizers for alfalfa grown on Brazilian acidic soils. Polyhalite may be considered as a replacment to KCl as a K source, as well as a donor of Ca, Mg, and S. Broad scale field experiments are required, however, to further confirm this conclusion under practical terms.	
Palavras-Chave: 	Liberação lenta.	
Thesagro: 	Absorção de Nutrientes; Acidez do Solo; Cálcio; Enxofre; Magnésio; Medicago Sativa; Potássio.	
Thesaurus Nal: 	Acid soils.	
Categoria do assunto: 	W Química e Física	
Registro original: 	Embrapa Pecuária Sudeste (CPPSE)	
Exemplares: 	CPPSE - (24368-1) - UPC - AP - DD - PROCI-2018.00018 - BER - 2018.00029 - DIS