Publication Date

1985

Location

Kyoto Japan

Description

Growth analysis was conducted to clarify the process of the regrowth, and the relation between LAI and plant height, percentage light penetration, CGR or NAR in the 2nd crops of Italian ryegrass (Lolium multiflorum) given 3 rates of fertilizer (20kg N + 10kg P205 + 17.5kg K20 ha-1, twice and 4 times). For the analysis, cubic regrassion curves were used, as they were fitted significantly by the changes of plant height, LAI, percentage light penetration and dry weight of whole plant with the regrowth. CGR (dt/dw) was obtained by the differentiation of cubic regression equation in the dry weight (w); NAR (CGR/LAI) was obtained from both of the quadratic equation of CGR and cubic equation of LAI. Under high fertilization, the plant height and LAI were maintained at a high level and percentage light penetration was reduced steeply, but NAR was maintained at a high level upto 2 weeks after cutting and declined to a slightly low level thereafter. The dry weight of whole plant and CGR were maintained at high levels with high fertilization. At a given LAI, the plant height and percentage light penetration were almost always at low levels, but CGR and NAR were always at high levels through the period of regrowth under high fertilization. It was concluded that the canopy structure was not improved, but the dry matter production was stimulated under high fertilization.

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Growth Analysis in the Regrowth of Italian Ryegrass as Affected by Fertilization Level

Kyoto Japan

Growth analysis was conducted to clarify the process of the regrowth, and the relation between LAI and plant height, percentage light penetration, CGR or NAR in the 2nd crops of Italian ryegrass (Lolium multiflorum) given 3 rates of fertilizer (20kg N + 10kg P205 + 17.5kg K20 ha-1, twice and 4 times). For the analysis, cubic regrassion curves were used, as they were fitted significantly by the changes of plant height, LAI, percentage light penetration and dry weight of whole plant with the regrowth. CGR (dt/dw) was obtained by the differentiation of cubic regression equation in the dry weight (w); NAR (CGR/LAI) was obtained from both of the quadratic equation of CGR and cubic equation of LAI. Under high fertilization, the plant height and LAI were maintained at a high level and percentage light penetration was reduced steeply, but NAR was maintained at a high level upto 2 weeks after cutting and declined to a slightly low level thereafter. The dry weight of whole plant and CGR were maintained at high levels with high fertilization. At a given LAI, the plant height and percentage light penetration were almost always at low levels, but CGR and NAR were always at high levels through the period of regrowth under high fertilization. It was concluded that the canopy structure was not improved, but the dry matter production was stimulated under high fertilization.