Influence of N, P, and K Fertilization on Yield and Mineral Composition of Native Bluejoint Grass on the Lower Kenai Peninsula, Alaska1
- Winston M. Laughlin,
- Glenn R. Smith and
- Mary Ann Peters2
Domestic grasses are difficult to establish and maintain in the Caribou Hills of the lower Kenai Peninsula in Alaska. Thus this 8-year study sought to determine native bluejoint [Cufurnugrostis cunadensis (Michx.) Beauv.] response to varying N, P, and K fertilization rates applied annually and stand persistence when two cuttings were made each growing season. A 4 × 22 factorial experiment with four N rates (67,134,201, and 268 kg N/ha) and two P and K rates (84 and 168 kg P/hq 93 and 186 kg K/ha) was established on Kachemak silt loam (thixotropic over loamy, mixed Typic Cryandept) at 366 m elevation. Concentrations of NO3−N, total N, P, K, S, Ca, Mg, and Si in the plants were determined and uptake of these constituents calculated, During this 8 years with two annual harvests and with fertilization the bluejoint stand became more dense. Each increasing N rate through 134 kg/ha generally increased the annual yield. Concentrations of N03−N and total N in both cuttings and annual N uptake were increased by each increasing N increment while the Si concentration of each cutting was depressed. Significant yield interaction between N and K occurred with greater response to N or K at the higher rates of the other. Application of P increased forage yield, P, Ca, and Mg concentrations, and P, K, S, Ca, and Mg uptake. Doubling the P rate further increased these values. Potassium application increased yield, K concentration, and P, K, and S uptake. Doubling the K rate increased the yield at higher N rates and decreased Ca, Mg, and Si concentrations and uptake. Ranchers in the lower Kenai Peninsula area of Alaska can now be assured native bluejoint can be the most important forage grass to provide supplemental winter livestock feed. Persistent high yields can be maintained with less cost than with any other presently known forage.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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