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From: [email-masked]
Date: 5 Jan 1995 20:32:51 -0000

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INTERNATIONAL AG-SIEVE  Volume VII, number 1   (SOIL FAUNA)
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-  Cuba's Composting

-  Stimulating Soils: an earthworm's approach

Below are some of the rough articles which will be included in the next issue 
(Vol VII, 1) of the International Ag-Sieve. Within the next week more articles 
will be posted. The purpose of this electronic version of the newsletter is to 
send out the soon-to-be-printed articles to you, the reader, in the hope that 
you will respond and comment on the contents. Please send your suggestions to:

[email-masked]

Once comments are read, stylistic changes are made according to suggestions, 
and some individual remarks will be added to the printed version under our 
Readers React column. I hope you enjoy this up-coming issue, and I look forward

to your reactions.

Sincerely,

Roger Bairstow
Communications Manager
Rodale Research Institute

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Cuba's Composting! 

Caught in a vice of economic sanctions, political pressures and faltering 
production, Cuba is faced with no alternative but to find alternatives to its 
past dependency on imports of fossil fuels, fertilizers, pesticides, animal 
feed and the like. Agricultural imports have been cut by as much as 80%. 
Consequently, the Cuban government has established programs designed for sound 
and effective soil management and have made earthworms one of the key agents in

their drive for agricultural sustainability. By using selected earthworm 
species, Cuban scientists have developed a full technological package for the 
production of humus from earthworms, a process known as vermicomposting or 
vermiculture, and generally recommend an application rate of 4 tons/ha of 
earthworm humus to most crops.

Compost production

Cuba's verimcomposting program started in 1986 with two small boxes of red 
worms, Eisenia foetida  and Lumbricus rubellus..  Today there are 172 
vermicompost centers that in 1992 produced 93,000 tons of worm humus. Several 
different institutions and companies are involved in vermiculture operations, 
but research is conducted primarily by the Institute of Soils and Fertilizers 
and the National Institute of Agricultural Sciences. 

The production of vermicompost requires a mixture of worm castings, organic 
material and bedding in various stages of decomposition. First, manure is 
composted for approximately 30 days aerobically, and then transferred to open 
vermicompost beds. At some sites like the Pinar del Rio vermiculture center, 
these beds are located in the shade of large mango trees which benefit from 
nutrients leached from the piles. The beds are approximately 1.5 meters wide 
and of varying length. The compost is mixed with soil and "seeded" with 
earthworms. Most vermicomposting operations in Cuba use cow manure as the 
primary source of organic material. Other sources include pig and sheep manure,

filter press cake from sugarcane, coffee pulp, plantains and municipal garbage.

Vermicompost beds are sprinkled with water to maintain optimum moisture and 
temperature requirements. The worms feed on the freshly applied compost at the 
top of the beds and deposit their castings in the lower levels. Compost is 
continually applied until the beds reach a height of approximately 0.9 meters  
after about 90 days. The worms are concentrated in the top 10 cm of the pile 
and scraped off or separated from the vermicompost in a screening process. The 
humus is either dried and bagged or used on-site as a soil amendment and 
fertilizer.

Beneficial Castings

The humus produced in vermicomposting improves soil nutrient content and 
permeability, helps control diseases that attack plants and stimulates plant 
growth. Cuban researchers have found that nitrogen concentrations are higher in

vermicomposting than in static compost piles. For instance, four tons of 
vermicompost per hectare can replace forty tons of cow manure per  hectare of 
tobacco, resulting in as much as a 36% improvement in yield. Earthworm castings

contain 1.5 - 2.2% Nitrogen, 1.8 - 2.2% Phosphorous, 1.0 - 1.5% potassium and 
65-70% organic matter, lasting up to five years in the soil.

Jorge Ramon Cuevas, the earthworm man of Cuba, states that scientists have 
experimented with several earthworm species for vermiculture, including E. 
foetida  and L. rubellus  and a Pheretima  species brought from the Philippines

to begin the national initiative. Work now focuses on two species thought to be

most useful under Cuban conditions: Eisenia andrei, which can tolerate the 
humid, subtropical Cuban climate better than E. foetida , and Eudrilus 
eugeniae, the African Red Worm. E. eugeniae  is less tolerant and prone to 
escaping when conditions are not quite right as compared to E. andrei . 
However, it produces more protein than E. andrei   and is useful as a 
supplemental animal feed.

Other Uses for the Earthworm

Worm populations under vermiculture can double in 60-90 days. Worms not used 
to seed new compost piles are dried and used as a supplemental protein for 
animals. Earthworms are useful as animal feed because they are high in protein 
and contain the amino acid methionine (4%), which is absent from feed grains. 
Cuban scientists have determined the correct balance of earthworm proteins in 
various animal feeds (10-40% in fish meal, 4% in shrimp feed and 6% in chicken 
feed).  They also discovered that chopping up earthworms releases enzymes which

quickly degrade the quality of the feed. Cuba's future plans include production

of earthworm excrement to be used as substrate for bacteria, which in turn will

be used as biofertilizer.

Extension and Expansion

Five experimental stations located in different parts of the country have 
responsibility for training new worm growers in their regions. Information is 
exchanged among these growers at an annual national conference on 
vermicomposting. National television programs and newspaper articles are used 
to help educate farmers, school children and the general public about 
vermiculture.

At the Soil Institute, plans exist for a vermiculture research facility, but 
construction has not started. The Institute is presently spearheading efforts 
to market and sell worm humus in 40 kg, 1 kg and 1/2 kg bags under the trade 
name Midas.  A 40 kg bag of Cuban worm humus can sell for as much as $80-100 
(US) on the international market, though humus production has not reached 
levels that permit significant exports. Income generating schemes have focused 
on joint production ventures and the sale of technical assistance for start-up 
vermiculture programs outside Cuba. Altogether, it looks as though Cuban 
vermiculture is proving to be a promising means of import substitution as well 
as profitable.

Gersper et al., Agriculture and Human Values, Vol. X, number 3, Summer 1993, 
pp.16-23.

Werner, Matthew, Cuban Agriculture Looks to Vermiculture, The Cultivar, Vol. 
12, No. 2, Summer 1994

Contact: 

Paul L. Gersper, Associate Professor, Department of Environmental Sciences, 
Policy and Management, University of California at Berkeley
Fax: (510) 642-0535

Matthew Werner, Center for Agroecology and Sustainable Food
Systems

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Stimulating Soils: an earthworm's approach

In the Cte d'Ivoire, something has been found can turn infertile, 
granite-derived soils of into a more hospitable land for the growth of certain 
plants. Remarkably, this "something" is no more than a handful of select 
earthworm species. Their incorporation into the soil has had beneficial effects

on nitrogen and phosphorous levels and plant growth.

Little is yet known whether tropical earthworms, with their diverse ecological 
strategies are able to stimulate plant growth, but scientists in the Cte 
d'Ivoire have attempted to prove just that. Their results not only demonstrate 
the positive effects earthworms can have on the soil and plants, but also 
highlight the importance in choosing earthworm species that are suited to the 
given environmental conditions if they are to increase agricultural 
productivity.

What and Where

Studies were conducted at the Station d'Ecologie Lamto in the Cte d'Ivoire 
where average annual rainfall is 1228 mm and the average monthly temperature 
ranges from 25.7{C in August to 28.8{C in February. The granite-derived, 
savanna soil is classified as a ferralsol  (7.5% clay, 14% silt, 29.4% fine 
sand, 46% coarse sand). 

Experiments were conducted to asses the influence of four species of 
earthworms on the growth of maize, the response of the grass Panicum maximum  
to the addition of two masses of eudrilid (JKL: what's that?) earthworms,  and 
the effects on Panicum maximum  in the transfer of nitrogen from the earthworm,

M. anomala, and microbial biomass to P. maximum .

Experiments 1 and 2

Similar procedures were used in the experiments testing the influence of four 
earthworm species on the growth of maize and the influence of Chuniodrilus 
zielae  and Stuhlmannia porifera  on the perennial grass, Panicum maximum . The

four earthworm species chosen for the first experiment consisted of:

1)      a mixture ofChuniodrilus zielae  and Stuhlmannia  porifera  (two small 
polyhumic        endogeic species);
2)      Hyperiodrilus africanus  (a pigmented, epi-endogeic species common in 
West  Africa);
3)      Ponotscoex corethrurus  (Glossoscolecidae, an endogeic species common 
throughout       the humid tropical zone but which does not occur at Lamto); 
and 
4)      Millsonia anomala  (a mesohumic endogeic species which dominates the 
Lamto    savannas).

Within three days of planting maize (experiment 1) and P. maximum  (experiment 
2), the biomasses of the five earthworm species (experiment 1) and Chuniodrilus

zielae  and Stuhlmannia porifera  (experiment 2) were added to 10 liter plastic

containers containing 2 mm-sieved soil from the top 10 cm of the profile. The 
containers were furnished with holes covered with a fine mesh to allow free 
drainage and prevent the entry or exit of earthworms and plant roots. The 
experiments, 12 weeks in duration, were conducted as a completely randomized 
design with four replications of each treatment for the first experiment, and 
five replications for the second. In experiment 2, live biomasses of 0.5 and 
1.0 g of  Chuniodrilus zielae  and Stuhlmannia porifera  earthworms were added 
to the five replication, and three seedlings were permitted to grow in each 
bucket.

In experiment 1, the maize plants survived poorly in the nitrogen-and 
phosphorus-deficient soil. Neither Pontoscolex corethrurus  nor H. africanus  
survived, and the biomasses ofC. zielae  andS. porifera  either remained 
constant or declined over the course of the experiment. The biomasses of M. 
anomala  declined similarly, although in the replications where both plants and

earthworms survived to maturity, M. anomala  biomass increased slightly.

For experiment 2, the mean above-ground biomasses of the grass, P. maximum , 
in each of the treatments at harvest were 3.75 g for the control and 6.98 and 
11.77 grams, respectively, for the treatments with the 0.5 and 1.0 gram 
earthworms.  It is clear that the presence of these earthworms led to a 
significant increase in the final biomass of  P. maximum  compared with the 
control treatment. However, in comparing the two treatments which contained the

0.5 and 1.0 gram earthworms, there was no significant difference in the final 
biomass of P. maximum . Over the course of the experiment, the earthworms' 
biomass increased substantially; to an average of 1.45 g in the 0.5 g treatment

and 2.03 g in the 1.0 g treatment.

N and P Transfer

To examine how nitrogen, transferred to a plant, is influenced by the presence 
of earthworms, the earthworms and the microbial biomass of the soil were 
labeled with 15N, a tracible element. The microbial biomass of the soil was 
marked by incubating the soil for a month with 15N-labeled ammonium sulphate 
and glucose mixed to attain a C:N ratio of approximately 15.  After one month, 
juvenile specimens of M. anomala  were introduced into the marked soil and kept

there for a month to ensure that there was adequate time for 15N to become 
present in the plant and earthworm biomass. P. maximum  plants were grown as in

the previous experiment. Three combinations were used: 1) labelled soil with 
unlabeled worms; 2) labeled soil without worms; and 3) unlabeled soil with 
labeled worms.

The harvested biomass of the P. maximum  plants for all treatments is 
presented in Table 1. Total biomass in the treatment with 15N-labeled M. 
anomala  was substantially higher than the corresponding treatment in the 
previous experiments with M. anomala . The reason for this is unclear. Higher 
P. maximum  biomass in the two remaining treatments may have been due to the N 
added in labeling the microbial biomass. In the two treatments where earthworms

were included, the worms grew actively throughout the experimental period. In 
the treatment of labeled earthworms and unlabeled microbial biomass, 
concentrations of 15N in the foliage and roots were only marginally higher than

in the unlabeled soil. Where the microbial biomass alone was labeled, both the 
earthworms and plant parts had significant accumulations of 15N.

Conclusion

The addition of earthworms to containers where the test plants were growing 
led to increased plant production.  This growth stimulation occurred at 
earthworm biomass levels found normally in field situations. Both C. zielae , 
S. porifera  and M. anomala  proved effective in growth stimulation. With 
additional biomass of approximately 4 g of live earthworms per container, it is

possible that the decline of growth stimulation is due to the formation of a 
poorly-permeable structure from excessive amounts of castings. Earthworms 
apparently survive less well at these higher biomass levels. A clear maximum 
value occurs in the relationship between earthworm biomass and the ratio 
above-ground: root biomass, suggesting that a higher above-ground production 
per unit mass of roots occurs in the presence of earthworms.

Earthworms have also been shown to facilitate the transfer of nitrogen and 
phosphate from the soil microbial biomass to the plant, and in the case of M. 
anomala , elevate microbial biomass levels in the roots. The casts of anecic 
(JKL: ??) earthworms and M. anomala  also appear to increase the availability 
of phosphate.

The failure of the maize plants to grow satisfactorily in the infertile Lamto 
soil suggests that the stimulatory effects of earthworms were insufficient to 
meet the nutrient requirements of the high-performing variety. The reasons for 
the failure of P. corethrurus  and H. africanus  to survive in the maize growth

experiments is unknown. P. corethrurus  does not occur in the Lamto area and H.

africanus  is found locally only in coconut plantations where more litter and 
locally higher organic matter levels are found.  Even M. anomala , which is 
adapted to these soils, failed to flourish in the absence of productive plants.

M. anomala  was better able to cope with the infertile soils in the presence of

P. maximum . This emphasizes the need to carefully select earthworms species 
based on their tolerance of particular soil and environmental conditions, if 
they are to be successfully employed to increase soil productivity.

Spain A., Lavelle P. and Mariotti A. (1992), Stimulation of plant growth by 
tropical earthworms. Soil Biology and Biochemistry 24, 1629-1633

Contact:

A.V. Spain, Davies Laboratory, CSIRO, Private Mail Bag, Aitkenvale, Queensland 
4814, Australia

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