The Long‐Term Impact of Phosphorus and Potassium Fertilization on Alfalfa Yield and Yield Components

Abstract

Addition of P and K fertilizer can increase alfalfa (Medicago sativa L.) yield and stand persistence, but the yield components associated with P‐ and K‐induced variation in agronomic performance are not clear. Our objectives were: (i) to determine the impact of P and K nutrition on productivity of a relatively old alfalfa stand; and (ii) determine which yield components are associated with changes in alfalfa forage yield. Treatments were a factorial combination of four P and five K rates replicated four times. Forage harvests occurred four times annually. Plant populations were determined in early December and late May each year. When compared to unfertilized plots, addition of P and K increased forage yield each year. Fertilization with P decreased plants m−2 at all K application rates, but especially in plots fertilized with P, but not K. By comparison, plots fertilized with K, but not fertilized with P, had the higher plant population densities. Although regression analysis eventually revealed a positive association between forage yield and shoots m−2 in 2003 and 2004, the greatest forage yields were not obtained in plots with the greatest plant population densities, shoots plant−1 or shoots m−2 Regression and path analysis revealed that improved forage yield in P‐ and K‐fertilized plots was consistently associated with greater mass shoot−1

Fertiliser management for higher productivity of established lucerne pasture

“…Low-K status also had a significant impact on the disease tolerance and persistence of lucerne (Grewal & Williams 2003). Berg et al (2007) reported a significant improvement in lucerne herbage yield with the addition of P and K, and a marked improvement in lucerne persistence with K addition.…”

Liming influence on soil chemical properties, nutritional status and yield of alfalfa grown in acid soil

“…Alfalfa is one of the most important forage crops worldwide because of its good forage quality, high forage yield in a wide range of environments, and high adaptability to different climatic conditions (Dordas, 2006;Berg et al, 2007;Zhang et al, 2008;Turan et al, 2009). Alfalfa is grown mainly for forage production while seed yield is secondary (Iannucci et al, 2002).…”

Impact of long-term organic and mineral fertilization on lucerne forage yield over an 8-year period

“…As was noted by Berg et al (2005), direct P and K fertilization was consistently associated with greater mass of individual shoots. Low P and K soil fertility reduced fibre concentrations in the forage (Lissbrant et al 2009) as well as persistence and productivity (Berg et al 2007). As was highlighted by Chmelíková et al (2015), holistic analysis including above-and belowground traits should be used for the evaluation of fodder crops.…”

“…At the study site, altitude is 338 m a.s.l., the mean annual temperature is 8.2°C and the mean annual sum of precipitation is 422 mm (Prague-Ruzyně Meteorological Station, 1955-2007. The soil type was classified as illimerized Luvisol.…”

“…Intensive agricultural cropping system requires large quantities of plant nutrients (Lloveras et al 2012) which highlight importance of suitable fertilization management. The impact of lucerne fertilization has been traditionally focused on effects of direct application of phosphorus (P) and/or potassium (K) in various combinations (Berg et al 2007, Macolino et al 2013. Direct application of nitrogen (N) or organic fertilizers for monoculture has been investigated rarely (Vasileva and Kostov 2015) because of high lucerne potential of N 2 fixation described by Carlsson and Huss-Danell (2003).…”