NITROGEN AND IRRIGATION EFFECTS ON THE YIELD OF POPPIES (PAPAVER SOMNIFERUM L)

The experiments described in this paper studied a number of alternative strategies for the application of nitrogen fertiliser and irrigation for poppies (Papaver somniferum L). In Experiment 1 nitrogen was applied as ammonium nitrate either banded at drilling at 20,60 and 80kg N/ha or top-dressed two weeks before flowering at nil, 40 and 80kg N/ha onto plots which had received 20kg N/ha banded at drilling.
Irrigation was applied at a deficit of 35mm by overhead sprinklers and continued until leaf senescence to give the four treatment totals: Iro = nil, Ir1 = 95mm, Ir2 = 216mm and Ir3 = 297mm.
The effects of both banded and top-dressed N on capsule morphine concentration were similar and very dependent on irrigation.
There were no effects of either banded or top-dressed N at Iro and increases of 10% at Ir1 and 24% at Ir2. At Ir3 the increases were only 5% and 11% for banded and top-dressed N respectively presumably due to leaching.
There was little effect of N on dry matter.
In contrast head yield was increased 20–40% with irrigation.

In Experiment 2, top-dressed N was applied as ammonium nitrate at nil, 20, 40, 80, 120 and 160kg N/ha with three overhead sprinkler irrigation treatments applied at a moisture deficit of 35mm: (i) Nil, (ii) Full irrigation until leaf senescence, (iii) Partial irrigation up to flowering.
Top-dressed N had no effect on capsule morphine concentration at nil or partial irrigation but gave an 8.8% increases with full irrigation.
The effect of N on dry matter varied with the irrigation treatment.
There was no effect at nil or full irrigation but N gave a 29% decrease in head (capsule + seed) yield with partial irrigation presumably due to osmotic effects in the soil solution.
Full irrigation per se increased head yield by 95%.

International Symposium on Medicinal and Aromatic Plants, XXIII IHC

J.C. Laughlin, B. Chung

https://doi.org/10.17660/ActaHortic.1992.306.63