Nitrogen and phosphorus fertilizations alter nitrogen, phosphorus and potassium resorption of alfalfa in the Loess Plateau of China

Abstract

Nutrient resorption from senescing leaves is a pivotal component of nutrient conservation strategy in a plant. Thus understanding the response of nutrient resorption to fertilization is of great help to minimize fertilizer use and further optimize fertilization management. However, little is known about how nutrient resorption responds to fertilization in N2-fixing species. Nitrogen (N) and phosphorus (P) fertilizers were applied at different rates to alfalfa stands in the Loess Plateau. N fertilization hardly affected leaf N and K resorptions, but tended to increase P resorption. P fertilization increased N and K resorptions but affected P resorption in various ways. However, effect of N or P fertilization was significantly interplayed by P or N rate. At N100P60, alfalfa had the maximum biomass accumulation and less leaf resorption. Therefore, alfalfa could be performed well with 100 kg N ha−1 and 60 kg P2O5 ha−1 in this region.