Nitrogen Fertilization or Legumes in Tall Fescue Pastures Affect Soil and Forage Nitrogen

Abstract

Including legumes in pastures improves forage quality and may reduce nitrate leaching into ground water. In a six‐year grazing experiment, ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) was fertilized with N at 80 lb/acre each August and April or was grown with either alfalfa (Medicago sativa L.) or red clover (Trifolium pratense L.) without N fertilizer with three replicates of each system in a randomized design. Stockpiled forages were winter grazed by stocker cattle and summer forages were harvested as hay. Soils were mixed Typic Hapludults. During years five and six, effects of N fertilization or the legume on soil N, N uptake, and forage yield were investigated. Soil NH4 and NO3 were higher in the A than B horizon. Soil NH4 was higher and NO3 was lower in fescue‐red clover soils than where N‐fertilized fescue or fescue‐alfalfa was grown. Soil nitrate did not exceed 3 ppm. Annual nitrogen uptake for the two sampling years in fescue‐red clover, fescue‐alfalfa, and N‐fertilized grass was 239, 277, and 162 lb of N per acre, respectively, with annual biomass yields of 4.7, 5.8, and 4.7 tons/acre. After six years, potential for NO3 leaching beyond the B horizon appeared low but may be influenced by legume species.

Legume-grass mixtures increase forage yield by improving soil quality in different ecological regions of the Qinghai-Tibet Plateau

“…Reasonable farming methods ( Gao and Xie, 2023 ) and planting patterns ( Spiegel et al., 2007 ) can improve resource utilization and result in increased yields. The cropping systems ultimately contribute to crop growth and development and yields ( Vines et al., 2006 ) by influencing soil physicochemistry ( Xiong et al., 2021 ), soil nutrients, soil enzyme activity in the cultivated layer ( Khatiwada et al., 2020 ), and the soil microbial system ( Bai et al., 2022 ).…”