Growth and carbon balance of a rice canopy grown in temperature-controlled conditions
1989
Laza, R.C. | Parao, F.T. | Akita, S. (International Rice Research Inst., Los Banos, Laguna (Philippines). Dept. of Agronomy)
The growth, nitrogen and carbon balance of a short-duration rice cultivar IR58 canopy grown to maturity in the field and at different day/night temperature regimes - 31/25 deg C (C Sub H), 27-23 (C Sub m) and 24/20 (C Sub L)- were evaluated. Plants in C Sub H grew faster and matured earliest. Growth in C Sub L was slower, but growth duration was longest and total biomass produced highest. Grain yield and harvest index were: FieldC Sub MC Sub LC Sub H, but their total dry weight were 1.3 Sub 8, 1.36, 1.67, and 1.54 kg/sq m, respectively. Percent nitrogen in active leaves, sheath and culm decreased towards maturity. It was low in plants grown under C Sub H. Maximum total nitrogen uptake around heading was less than 20 g N/sq m in all temperature regimes. At higher temperature, crops after heading showed decreased growth efficiency (GE). The higher GE at C Sub L after heading seems to favor a higher total biomass at harvest possibly because of lesser energy loss by maintenance respiration of the rice canopy.
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