Nitrogen Nutrition and Growth Relations of Tall and Intermediate Wheatgrasses1
- L. O. Hylton,
- D. R. Cornelius and
- A. Ulrich2
Alkar tall wheatgrass, Agropyron elongatum (Host.) Beauv., and Greenar intermediate wheatgrass, A. intermedium (Host.) Beauv., grown separately in nutrient solutions to which NO3- had been added at 0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16, or 32 meq of NO3- per liter. Other nutrients were present in ample amounts. The two grasses were grown concurrently in full greenhouse sunlight for 36 days. Total dry matter production (tops + roots) was significantly reduced with less than 4.0 meq of NO3- per liter. Average maximum top weight (oven-dry) was 2.02 g per plant for tall wheatgrass and 2.76 for intermediate wheatgrass. These top weights were obtained with 8, 16, or 32 meq of NO3- per liter. In a common and favorable environment, growth of intermediate wheatgrass was more rapid than that of tall wheatgrass.
Accumulation and distribution of nitrate-N varied slightly within the plants. At high NO3- treatments, matured blades of tall wheatgrass had the highest nitrate-N concentration (14,600 ppm) whereas stems of intermediate wheatgrass had the highest (16,000 ppm) concentration. Immature blades had the lowest nitrate-N concentration, about 8,200 and 9,200 ppm, respectively, for tall and intermediate wheatgrasses. Recently matured blades of intermediate wheatgrass had higher percentages of total-N, nonsoluble-N (protein-N), and crude protein than did those of tall wheatgrass. Soluble-N and nitrate-N concentrations were generally higher in tall wheatgrass than in intermediate wheatgrass.
The critical nitrate-N concentrations for growth of these two wheatgrasses is about 500 ppm nitrate-N in recently matured blade tissue, dry basis.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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