Table of Contents
Evans, D.W. and A.H. Hang. 1993. Kenaf in irrigated central Washington. p.
409-410. In: J. Janick and J.E. Simon (eds.), New crops. Wiley, New York.
Kenaf in Irrigated Central Washington
David W. Evans and An H. Hang
- MATERIALS AND METHODS
- Table 1
- Table 2
- Fig. 1
- Fig. 2
Kenaf (Hibiscus cannabinus L., Malvaceae) is an annual crop with uses
for fiber, forage and paper pulp (White et al. 1970; Husingi 1989). In the
continental United States, kenaf has been most productive in the southern
states, but it may also have potential in northern regions. We are
investigating the plant development and yield of irrigated kenaf in central
Washington State where an annual pulp crop could further broaden our
agricultural diversity and reduce pressure on forest resources.
Three cultivars of kenaf were tested on a preliminary basis in 1987 and four
were tested in 1990 at WSU-Prosser. This site is 46° 15' N, 119° 45' W
and 275 m above sea level. It averages 160 frost-free days and 0.19 m annual
precipitation, mostly in the winter months. Kenaf was raised both years on a
silt loam (coarse-silty, mixed, mesic, Xerollic Camborthids) fertilized and
furrow irrigated as for maize (Zea mays L.) grain production. The crop
was seeded in rows spaced 0.76 m apart at a target population of 25
thousand/ha. Both plantings were surrounded by maize. Stands were hand
In 1987, single, 6 m long, unreplicated plot rows of 'Everglades 41' ('EV41'),
'Everglades 71' ('EV71'), and 'Tainung 1' ('T1') were planted on 7 May. In
1990, 'EV41', 'EV71', 'T1', and 'Cuba 2032' ('C2032') were seeded on 11 May, in
plots 6 rows wide by 20 m long using a randomized complete block design with 5
replications. Plant height was measured monthly in 1987; both height and leaf
and stem weight (10 plant samples) were determined weekly from 23 July to 8
Oct. on 'EV41', 'EV71', and 'C2032' in 1990. Defoliated stem yield was
determined on all entries from 3 m of each single row in 1987 and from 4.6 m of
an interior row of each plot in 1990.
Monthly degree days (10°C base) as determined from air temperatures recorded
600 m from the plot area were warmer than average in May and June 1987, and in
July-September 1990 (Table 1). Kenaf grew taller early in the season and
reached a greater final height in 1987 than in 1990 (Fig. 1). Flowering began
in mid-September both years which was too late to result in viable seed
Leaves made up a constantly decreasing fraction of total top weight over the
period July 23-Oct. 8 in 1990 (Fig. 2). The leaf fraction in 1990 was
described by the relationship y = 35 - 3.67 + 0.014 x2
(r2 = 0.898), where y = fraction of leaf in total top growth (g
leaf/kg total top, dry matter basis) and x = days with July 23 = day 1. Prior
to the final yield harvest both years, frost killed the leaves which dried and
dropped from the plants, leaving bare stalks.
Yields of 'EV41' and 'T1' exceeded 22 Mg/ha in 1987 (Table 2). 'EV71' did not
establish well and consequently yields were very low. In 1990, yields ranged
between 11 and 14 Mg/ha with 'T1' yielding most, but differences were only
significant at the 10% level. The upper ends of kenaf stems may be discarded
when kenaf is harvested for fiber (Hays 1989). This stem tip material has
potential as animal feed. At yield harvest in 1990, kenaf tops were separated
by hand into the basal 6 m and all material above 6 m, and weighed separately.
The basal 6 m ranged from 9.3 to 10.4 Mg/ha with no significant cultivar
differences. The stem tips ranged between 2.0 ('C2032') and 2.6 ('T1') Mg/ha
which was significant only at the 10% level.
A yield of 11 to 23 Mg/ha compares favorably with an average hybrid poplar
yield of 23.6 Mg/ha per year over a four year period in Washington (Heilman and
Stettler 1985). This kenaf yield, however, was obtained on single unreplicated
rows and is likely to represent an upper extreme. Average yields of 11 to 14
Mg/ha, as found in 1990, appear more realistic and still approach those
reported from some of the more southern growing areas [e.g. 13 to 21 Mg/ha for
1988 in Oklahoma as reported by Dag et al. (1989); 13.6 to 20.1 Mg/ha for 1986
in California as reported by Robinson (1988)]. Based on the height and yield
comparisons of 1987 and 1990, it appears that warm temperatures early in the
growing season may have an important influence in establishing early growth and
maximum performance. The economic prospect of kenaf as a viable central
Washington crop, however, will require a stable production area, consistent
high yields and the availability of a processing facility set up to handle the
- Dao, T.H., W. Lonkerd, S. Rao, R. Meyer, and L. Pellack. 1989. Kenaf in a
semi-arid environment? Its water requirement and forage quality in Oklahoma.
Agron. Abstr. p. 130.
- Hays, S.M. 1989. Kenaf tops equal high-quality hay. Agr. Res. 37(6):19.
- Heilman, P.E. and R.F. Stettler. 1985. Genetic variation and productivity of
Populus trichocarpa and its hybrids. II. Biomass production in a 4-year
plantations. Can. J. For. Res. 15:384-388.
- Husingi, G. 1989. Agricultural fibres for paper pulp. Outlook on Agr.
- Robinson, F.E. 1988. Kenaf: a new fiber crop for paper production. Calif.
- White, G.A., D.G. Cummins, E.L. Whitely, W.T. Fike, J.K. Greig, J.A. Martin,
G.B. Killinger, J.J. Higgins, and T.F. Clark. 1970. Cultural and harvesting
methods for Kenaf . . . an annual crop source of pulp in the southeast.
Production Res. Rpt. 113, USDA/ARS. Washington, DC.
Table 1. Monthly mean degree days (°C; 10°C base) at Prosser,
|Month ||52-yr. ||1987 ||1990|
|May ||147 ||216 ||128|
|June ||247 ||332 ||281|
|July ||351 ||332 ||414|
|Aug. ||328 ||352 ||366|
|Sept. ||203 ||261 ||299|
|Oct. ||28 ||74 ||33|
Table 2. Kenaf stand and dry matter yield at Prosser, Washington.
|Year ||Cultivar ||No. plant/ha |
|Total top dry yield|
|1987 ||Everglades 41 ||254 ||23.1|
| ||Everglades 71 ||56 ||6.3|
| ||Tainung 1 ||185 ||22.3|
|1990 ||Everglades 41 ||144 ||11.4|
| ||Everglades 71 ||198 ||12.4|
| ||Tainung 1 ||205 ||14.0|
| ||Cuba 2032 ||196 ||11.4|
| ||LSD (5%) ||28 ||---|
| ||CV (%) ||11.1 ||13.8|
Fig. 1. Kenaf heights at Prosser, Washington; averages of 'EV41' and
Leaf fraction of Kenaf at Prosser, Washington in 1990; g dry
leaf/kg total dry top.
Last update September 15, 1997