Biomedical Engineering Reference
In-Depth Information
Fig. 13.2 Cuphea
seedlings emerged
13-mm in depth or broadcasted on the soil surface; however, lack of soil moisture at
the surface may delay emergence in a broadcast seeding.
Optimum growth and yield is achieved by planting in early to mid-May in west
central Minnesota. Days from emergence to initial flowering decreased and growth
rate increased as seeding date was delayed [
7
]. Sowing too early when soil
temperatures are below 10
C can lead to poor stand establishment, while sowing
at the optimum recommended time lengthens the period for vegetative growth
including root development, which typically translates into greater seed and oil
yields [
7
,
73
].
Roath [
57
] showed that as cuphea seeding rate increased from 1.5 to 4.5 kg ha
1
,
so did the number of plants established. Recommended seeding rates in Minnesota
are 9-12 kg ha
1
[
8
,
9
]. Plant densities between 118 and 228 plants m
2
did not
significantly affect seed yield [
8
]. Also, increasing row spacing between 0.13 and
0.75 m did not have an effect on seed yield. The number of branches and the number
of seed capsules increase with less dense stands due to the plasticity of cuphea
plants [
8
].
Cuphea Nitrogen Requirement
There is little reported on the effect of nitrogen fertility on cuphea seed yield, oil
content, or oil composition. The cuphea grower's guide, created to give guidelines
to farmers in Minnesota, recommends using a band application of fertilizer placed
5 cm to the side and 5 cm below seed placement. For most soils, the recommen-
dation was to apply 45 kg ha
1
of potassium sulfate (0-0-20-7) along with
224 kg ha
1
of diammonium phosphate (18-46-0) and 112 kg ha
1
of urea (46-
0-0) [
8
]. The first commercialization efforts with cuphea started in Morris, MN, in
2004. Producers planted between 2 and 4 ha of cuphea and fertilized their fields
Search WWH ::
Custom Search