Dynamics of biomass, nitrogen and carbon in shoots and roots of a ryegrass catch crop during winter
1994
Sjoedahl Svensson, K. | Clarholm, M. (Sveriges Lantbruksuniv., Uppsala (Sweden). Inst. foer Ekologi och Miljoevaard)
To quantify N uptake and root growth, root and shoot development of Italian ryegrass (Lolium multiflorum, Lam.) undersown in spring cereals on sandy loam (Halland SW Sweden) was monitored during two winters, in 1988/89 and 1990/91. Two techniques for shoot sampling were used. Shoot biomass was 22-34% higher when shoots were pulled, the method used for the data below, compared to shoots cut at the soil surface. The latter method would, however, give a correspondingly higher, but more variable root biomass. Peak biomasses (DM) amounted to 3200 and 3800 kg ha-1 respectively, of which 40% was roots. The nitrogen content of the ryegrass reached a maximum of 59 kg N ha-1 in February 1989 and 58 kg N ha-1 in November 1990. The dry matter root/shoot ratio varied from 0.5 to 1.3 while the ratio of N in roots/N in shoots varied from 0.3 to 1.4. N uptake after harvesting the main crop was estimated at 45 kg ha-1 for 1988/89 and 21 kg ha-1 for 1990/91. Plant nitrogen content increased both as a result of an increase in nitrogen concentration in the shoots and as an overall increase in biomass.
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