Yield, Percent Nitrogen, and Total Nitrogen Uptake of Various California Annual Grassland Species Fertilized with Increasing Rates of Nitrogen¹

Abstract

Synopsis Near maximum yields resulted where 80 pounds N per acre were applied, but carryover was measurable only where 160 pounds were used. In nonleguminous plants, percent N increased with N rates during the vegetative stage, but at maturity it was less where 40 pounds N were applied than in the control. N uptake increased with N rate during winter, but uptake on unfertilized plots during the spring approximated that on plots receiving 40 pounds of N.

Effect of Site Class and Rainfall on Annual Range Response to Nitrogen and Phosphorus

“…Increasing the nitrogen rate to 120 lb./acre markedly increased the response to phosphorus (Table 4). These results contrast with those obtained by Hoglund et al (1952), and Jones (1960 and1963) which showed the nitrogen-phosphorus interaction on annual range to be generally insignificant. With an application of 150 lb.…”

“…of nitrogen, respectively. Increased grass yields as well as a relatively greater contribution of grasses to total forage yield had been reported by Jones (1963), Rossiter (1966), and Yitzchak and Seligman (1969). Dry matter production of leguminous species, present at Site No.…”

“…Forage yield response to nitrogen fertilizer application on range soils has been reported by many investigators (Hoglund et al, 1952;McKell et al, 1959;Jones, 1960;Jones and Evans, 1960;Woolfolk et al, 1962;Jones, 1963;and Conrad et al, 1966). Most of this research has been conducted in the coastal mountain areas of the central and northern parts of the state and in the foothills on the west side of the Sierra Nevada Mountains.…”

“…One hundred percent of the former and 90% of the latter yield increase was a residual effect. Jones (1963) has reported a residual effect of nitrogen, but only at the 160-lb./acre rate. These results indicate that the residual effect of relatively low rates of fertilizer on production during the second and third year after application is an important consideration in planning a fertility program on annual range, especially in southern California.…”

“…Phosphorus deficiency on annual range in California is much less widespread than nitrogen deficiency. No response to phosphate fertilizers at inherent levels of available nitrogen were reported by Hoglund et al (1952) and Jones (1963). Where nitrogen fertilizers were also applied forage yield increases from relatively high phosphorus applications were reported by McKell et al (1959) and Jones and Evans (1960).…”