Application of cattle manure, zeolite and leonardite improves hay yield and quality of annual ryegrass (Lolium multiflorum Lam.) under semiarid conditions

A field experiment was conducted under semiarid conditions to investigate the effect of cattle manure (20 and 40 t ha -1), zeolite (250, 500 and 750 kg ha -1), and leonardite (250, 500 and 750 kg ha -1) applications on hay yield and nutrient quality of annual ryegrass. Application of manure, leonardite, and zeolite increased ryegrass hay yield by 4, 24 and 47%, respectively compared with the control. In all fertilizer levels, the crude protein (CP) content was greater than the control and increased as the level of each fertilizer was increased. Most fertilizer treatments (except from the first level of cattle manure) gave higher CP yield than the control. All fertilizers increased the content of K, S, Ca, Mg, Fe, Mn and B of ryegrass hay as compared with the control, whereas they had no significant effect on Cu and Zn content. The content of most minerals increased as the amount of manure and leonardite applications increased. In conclusion, all fertilizers (especially zeolite) showed great potential for use in organic agriculture as they can improve plant growth and soil conditions in the long term.