Influence of Nitrogen and Potassium on the Yield and Chemical Composition of Orchardgrass¹

Abstract

Synopsis Nitrogen increased orchardgrass yields significantly throughout the season. However, potassium produced a significant yield increase only at the third harvest. Both nutrients depressed the percent total fructose of the sheaths during the first two growth periods. This effect was reversed for nitrogen during the third growth period. Asparagine accumulated abnormally in the second and third harvests when potassium fell below 1.6% of the dry weight.

Yield and chemical composition of Dactylis glomerata as influenced by genotype and management

“…Di early summer, the longest-deferred plots produced greatest yields, while during late summer, all clipping systems yielded approximately the same. As previously reported by Griffith et al, (1964), they found that high N fertilization lowered the total fructose level of the orchardgrass stubble during the early part of the growing season. more total production from 3 than 5 cuttings across all levels of applied N. They also found that less frequent harvesting improved the efficiency of N in terms of dry matter production but had little effect on crude protein.…”

“…They found a yield increase due to K when the percent K in the forage was 1.6# or less which corresponds very closely to the K percent found in orchardgrass at which an abnormal asparagine content was observed as reported by Griffith et (1964). Laughlin and Restad (1964) also found that in general K2S0^ was not superior to KCl as a K source for bromegrass.…”

“…Table 2 shows that exchangeable soil K was differentially reduced as the N rate increased. The percentage K in the forage was above 1,5 which was the value at which possible yield limitations could result as discussed by Mortensen et al (1964) and Griffith et al (1964) for all harvests except forage harvest 4, I967 (Table 2?). It is evident that under high rates of applied N an annual application of 110 kilograms per hectare of K is not sufficient to sustain a satisfactory K level in the forage.…”

Physiological Responses to Nitrogen in Plants

“…The same situation is recognized also in some other species, for example, in orchardgrass (Griffith, Teel, and Parker, 1964;Colby et aI., 1965;Auda et aI., 1966) and coastal bermudagrass (Adegbola and McKell, 1966).…”

Yields, densities, weight of roots, and carbohydrate levels of perennial forages as affected by method of establishment

“…Conversely, increased amounts of potassium have resulted in higher levels of carbohydrates in alfalfa seedlings (Matches, et al, 1963;and Re id, Lathwell, and Wright, 1965). There appears to be a balance required between potassium and nitrogen for accumulation of carbohydrates and ' normal nitrogen metabolism and protein synthesis (Griffith, Teel, and Parker, 1964;and MacLeod, 1965). Wardlaw (I968) stated carbohydrate accumu lation by nitrogen-deficient plants indicates that the growth processes of cell division and cell expansion are more affected than photosynthesis or translocation of photosynthate out of leaves.…”