Winter Survival, Yield and Yield Components of Alfalfa as Affected by Phosphorus Supply in Two Alkaline Soils

Abstract

Alfalfa (Medicago sativa L.) is an important forage for the development of herbivorous animal husbandry, which is widely planted in the cold climate areas of northern China, where there is low overwintering and forage yield in production, and fertilization is a vital production strategy. A field study was conducted to determine the response of alfalfa’s winter survival rate, yield, and yield components to different gradients of phosphate (P) fertilizer (0, 45, 90, and 135 kg P2O5 ha−1) in two types of low-phosphorus alkaline soils. The results show that the winter survival rates and forage yield increased at first and then decreased with the increase of P application; the greater winter survival rates were achieved at 45~90 kg ha−1 of P fertilizer applied, while the greater forage yield were achieved at 90 kg ha−1 in the two sites, and the suitable P fertilizer application rates for greater winter survival were less than those for greater forage yield; plant height and shoot mass made a greater contribution to forage yield than other yield components. To pursue greater forage yield, the suitable P fertilization rates for aeolian sandy soil and silt loam soil are 108.1 and 78.3 kg ha−1, respectively, based on the regression equations. Therefore, in cold winter and soil P deficiency areas, applying P fertilizer can be used as an effective strategy to improve alfalfa’s forage yield and persistence, and the most appropriate amount of fertilizer should be determined according to climate and soil conditions.