Plant consists of approx. 10% roots, 60-70% stems, 15-20% lvs; 5-15% seed. Chemical composition: 80%dm, 90%cellulose and hemicellulose, 4% lignin. (from Bioresource Hemp, J.E.G van Dam).

from R. Kozlowski (Poland):
recommended ratio of nutrients:
N:P:K
1:0.7:1.5 (fiber)
1:0.8: 1 (seed)

or about:
90-120kg/ha N
70-100 P2O5
150-180 K2O
15-20 CaO

van der Werf's study showed lower N gives better uniformity of stand and less self-thinning (approx 70kg N/ha). Hessler (Hessler, L. E. 1947. The effect of fertilizers on the chemical composition and quality of dew-retted hemp fiber. J. Am. Soc. Agron. 39:812-816.) showed high nitrogen increases protein in fiber and decreases strength and quality of fiber.

sow @ 8-10 C
for fiber: seed rate 60-70 kg/ha, 15-20cm row spacing (7-15cm, 450-500 seeds/sq.m more common in Ukraine and probably closer to traditional US practice.)
3-4cm deep

for seed 10kg/ha @ 50cm spacing.

Ian Low reports their experience: yields from farmer's field range from 5T/ha to 9.5T/ha; ylds in replicated trials, 10-14T/ha

From Holland:
Yield of hemp varies between 10-15 ton dm/ha; fiber yld ~1.5-2.0 t/ha.

Dempsey (1975) presented these figures in his book (Fiber Crops):
(note: I converted to lbs/A from his kg/ha)

Ky hemp in WI used to give 3T/A dry-retted stalk, which yielded about 1000lbs fiber. A yield of 1750 lbs fiber was obtained in KY in 1934 from the improved strain Chinamington.

ADVICE from "A Report on the Culture of hemp In Europe," by Chas. R. Dodge, 1898. p8.

"A rotation of crops is practiced, hemp alternating with grain crops, although MM Girardin and Du Breuil state that it is also allowed to grow continually upon the same land. Regarding this mode of cultivation, they consider it is not contrary to the law of rotation, as by deep plowing and the annual use of an adundance of fertilizers the grouind is kept sufficiently enriched for the demands which are made upon it. If the soil is not sufficiently rich in phophates or the salts of potassium, these must be supplied by the use of lime, marl, ground bone, animal charcoal, or ashes mixed with prepared animal compost. Even hemp-cake, the leaves of the plant, and the "shive" or "boon," may be returned to the land with benefit. This high fetilizing is necessary, as "the hemp absorbs the equivalent of 1,500 kilos of fertilizers per every hundred kilos of fiber obtained."