Response of Nitrate and Ammonium on Growth of Prosopis Velutina and Simmondsia Chinensis Seedlings

摘要

The objective of this study was to determine whether mesquite (Prosopis velutina) and jojoba (Simmondsia chinensis) seedlings have a preference for the ammonia or nitrate form of nitrogen (N) to maximize growth and minimize N leaching when seedlings were grown in sand culture. Seedlings were fertigated with different ratios of NH₄⁺:NO₃⁻ to determine effects on shoot and root growth and N leaching. Nutrient solution containing 67 % NH₄⁺: 33 % NO₃⁻ resulted in greatest biomass of mesquite seedlings after 120 days of fertigation. N tissue concentrations of mesquite seedlings were highest for plants supplied with 100% ammonium. N leachate remained stable until 12 weeks after the onset of treatment, but increased significantly by week 16. Dry weight of jojoba seedlings did not differ throughout the experiment regardless of the nutrient solution provided, however N tissue concentration in jojoba seedlings fertigated with 100% ammonium was twice as high as that of plants fertigated with 100% nitrate.