Determinación de cocientes críticos K/P en praderas a partir de un ensayo multifactorial de fertilización

• Sinclair, A. G. ^[2] ; Besga, G. ^[1] ; Oyanarte, M. ^[1] ; Rodríguez, M.
  1. [1] Gobierno Vasco-Eusko Jaurlaritza

     Gobierno Vasco-Eusko Jaurlaritza

     Vitoria, España

     
  2. [2] Ag Research. Invermay Agricultural Center. Prívate Bag. 50034 Mosgiel (Nueva Zelanda)
• Localización: Pastos: Revista de la Sociedad Española para el Estudio de los Pastos, ISSN 0210-1270, Vol. 24, Nº. 1, 1994, págs. 69-80
• Idioma: español
• Títulos paralelos:
  • Determination of ideal K/P ratios in pasture plants from a multi-rate factorial fertiliser trial
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• Resumen
  • español

    Se llevó a cabo una investigación para estimar la utilidad de los cocientes de nutrientes en el diagnóstico del estado nutricional de plantas pratenses. Un ensayo NPK con 6 dosis de P, 3 de K y 2 de N se estableció en una pradera de trébol blanco y raigrás inglés. En 1988 se determinó la producción de materia seca dando 4 cortes a la pradera. Para cada tratamiento se calcularon las respuestas potenciales al P y K (RPP y RP|

  • English

    An investigation was eonducted to assess the valué of herbage nutrient ratios for diagnosing nutritional status of pasture plants, and to determine the K/P ratio whieh corresponded to good nutritional balance between these elements. A P x K x N factorial trial with 6 rates of P, 3 rates of K and 2 rates of N was established on a newly-sown pasture of white clover and ryegrass. Herbage was cut 4 times in the following year and measurements of DM production and ehemical composition of white clover and total herbage were made. For each treatment, potential responses to P and K (PRP and PR]<) were calculated, these being the máximum additional yields which have been obtained with higher applications of P alone or K alone, respectively. Valúes for (PRP - PR|<) were plotted against K/P ratios in white clover and total herbage. White clover K/P ratios greater than 5.4 were nearly always associated with positive valúes of (PRP - PR]<) in total herbage (i.e. P more deficient than K), and vice versa. Thus a K/P ratio of 5.4 in white clover was taken to indícate ideal nutritional balance of K and P in the pasture and was described as the critical K/P ratio. K/P ratios in total herbage also differentiated well between treatments more deficient in P and those more deficient in K, but the critical level was much higher, due apparently to luxury uptake of K in ryegrass. It was concluded that the K/P ratio in the white clover component was a useful indicator of nutritional balance in a pasture; and it was suggested that the method developed for deriving the critical K/P ratio could be used to derive DRIS ratio norms when the conventional DRIS method was not applicable.