Response of an Orchardgrass-Subclover Mixture in Western Oregon to Different Clipping and Fertilizing Practices

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Allen Press and Society for Range Management are collaborating with JSTOR to digitize, preserve and extend access to Journal of Range Management. NITROGEN CONTENT 147 described above. One point for each of the four experiments relating nitrogen content to per cent maximum yield in the check treatment was plotted on Figure 1. All four are within the 95 per cent confidence belt. DiscussionA relationship between the nitrogen content of range grass and the yield response to nitrogen fertilization has been found. This relationship could be useful in assessing the yield response of a site from the nitrogen analysis of the grass. Some burning occurred from the higher rates of nitrogen application. However, it seems difficult to avoid burning entirely if rates high enough to attain maximum yields are to be used. Earlier application of the fertilizer in September might reduce the burning. The treatments in these experiments were all applied in the very late fall.The stage of maturity at har2Range ecologist, Research Station, Kamloops, B. C., Canada; private communication.vest is critical, because the nitrogen content is still falling rather rapidly. According to MacLean2, the nitrogen content falls from 2.40 per cent at the leafy stage to 1.39 at flower, 1.05 at seed, 0.66 at seed-set and 0.49 at the cured stage. Therefore, care must be taken to harvest at the chosen maturity to reduce variation in maturity to a minimum. SummaryThe nitrogen content of range grass has been shown to be related to yield response to nitrogen fertilizer. A comprehensive yield response experiment on Agropyron inerme (beardless wheatgrass) gave the basic relationship between nitrogen content and yield. The linear regression equation is LOG (100-y) = -0.9073 (%o N) + 2.3670 where y is yield expressed as a per cent of the maximum yield obtained in the experiment. A series of four test experiments was used to evaluate the relationship. The yield of the check plots expressed as per cent maximum was plotted against nitrogen content. The points from all four experiments were within the 95%o confidence belt of the regression line. The data suggest that nitrogen analysis of range grass could be used as a measure of the fertilizer response to be expected. Grass was harvested at the seed-set stage of maturity.