Responses of Several Sub-Tropical Crops

to Applications of Humus and Marine Materials

 A. R. Kingman
 Horticulturist
 For Diversified Marketing Services
 1-2 Estate Tabor-Harmony
 St. Thomas, Virgin Islands 00802


 For a number of years the need has been apparent for a means
of replenishing depleted organic matter in soils or adding organic
matter to poor soils. Lignitic or coal type deposits offer an abun-
dant source of humic acid, containing humus for replenishing
and maintaining a high level of soil organic colloids.
 Many countries, including the Soviet Union, France, England,
and Norway have conducted extensive research with humus and
seaweed as materials to provide humic substances for soil
building, micronutrients and growth regulating substances for
improvement of soil fertility and tilth, as well as for enhancement
of plant growth and development.
 Besides providing a source of nutrients for plants, humus, in-
cluding seaweed, has fundamental effects on the physical proper-
ties of soil (water holding capacity for example). Humus materials
can also determine in large degree such physiochemical properties
as the exchange capacity and buffering properties: these proper-
ties are of great importance in nutrient uptake by the plant and
nutrient retention in the soil. They also have the added effect of
suppressing the deleterious effects of soil acidity.
 A great deal of the research on the use of humus and seaweed
materials in agriculture in the United States has been conducted
at Clemson University, with applications to numerous fruit,
vegetable, and ornamental crops. The purpose of this body of
research was to examine alternative methods of soil and crop
management.
 The research discussed herein studied the use of humus and
seaweed materials as they relate to soil management, crop pro-
duction, yields and quality, while manipulating recommended
rates of conventional inorganic fertilizer regimes using several
sub-tropical crops.
 Tests of the sub-tropical and other crops grown with applica-
tions of humus, with and without the addition of commercial in-
organic fertilizers and/or marine materials (seaweed), conducted
under greenhouse, small plot and field conditions resulted in
significant differences over controls both in crop yields and quali-
ty. Controls used were standard growing practices for the crops 
recommended inorganic fertilizer rates. Crops included pineap-
ple (Red Spanish), tobacco, corn, cotton, schefflera, tomato,
bean and several minor floral crops.
 All plants were grown in soil amended with humus and/or
seaweed. Additionally, seaweed sprays were applied three times
during the growing season to foliage and floral crops. Results with
all crops revealed significant differences over controls (0 fer-
tilizer/or standard recommended fertilizer rates) in the quantity
of recommended rates of commercial, inorganic fertilizer re-
quired to produce the crops with no reduction in yields or quali-
ty. For example, with pineapple, number of crowns and fruit,


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fruit size and weight, pH, core size, vitamin C and soluble solids
resulted in no significant differences over standard fertilizer con-
trols when grown in humus amended soil with one-half of the
standard (recommended) fertilizer rate.
 Overall results in every crop listed in this report were improved
or equal to standard growth, development and production, with
no reduction in total yields or quality, with reduced standard, in-
organic fertilizer applications, when humus and/or seaweed
sources were used as soil amendments and/or foliar sprays.
 The significance of the research discussed herein is the ap-
plicability of the natural, organic substances to improved
management and growth of a wide array of crops, subtropical or a
number of others that are suitable for growth under a variety of
environmental conditions. The use of humus and marine
materials offers great potential for soil management and crop pro-
duction in the Caribbean.









 At the present time, a more detailed paper is being prepared.
Within the near future it will be made available to persons who
attended the 1984 Meeting of the Caribbean Food Crops Society,
as well as to other interested parties.
 Diversified Marketing Services plans to have a commercial pro-
duct available in the Caribbean shortly. DMS endorses the ap-
proach taken by the Caribbean Food Crops Society, whereby ap-
plied technology is made available to farmers as part of a
cooperative effort between colleges and universities to involve
farmers themselves in testing new approaches to crop production.
Accordingly, DMS invites inquiries from interested parties.
Technical considerations may be addressed directly to Dr.
Kingman, while inquiries about the availability of organic
humate and marine materials should be directed to Mr. Glenn R.
Tobey.
Alta R. Kingman, Ph.D. Phone: 1-803-654-4724
DMS Horticulturalist (evenings)
309 Woodland Way, Clemson, SC 29631
Glenn R. Tobey Phone: 1-809-775-1719
DMS President (evenings)
1-2 Estate Tabor-Harmony, St. Thomas, USVI 00802

 PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX