Our first project goal was to develop commercial quality wood seedlings through a production system based on forestry tube containers. The motivation behind this goal was to replace the current wood seedling system in use in Puerto Rico which relies on plastic bag containers. The current system was judged to be unsustainable due to its economic and environmental costs, and also agronomic deficiencies. The tube container system was based on 3 components: Large Deepot cell containers supported by trays, non soil growing mix based on organic materials, vermiculite, perlite and pumice, and hand watering irrigation with sprinkler water cans.
Our second goal was to provide the tube seedlings for farmers to combine coffee with non-traditional precious wood trees. Besides higher returns, precious woods provide shade on coffee crops and other multiple benefits on natural resources.
The results demonstrate that deepot cell containers solve the problem posed by bagged wood seedlings at the nursery and to coffee farmers. Tubed seedlings showed adequate development above ground, and root systems superior to bagged seedlings, and faster establishment. So far, survival rates have been good. Production costs for the tube seedlings are much less than the bag product and the environmental impact is minimal.
Coffee, one of the largest agricultural sectors with 14,000 limited resource farmers, was introduced to Puerto Rico in 1755. Coffee was first produced in Puerto Rico by thinning native woodland and then planting coffee. The original coffee farmers soon came to identify native species with the best characteristics for coffee shade and wind protection from hurricanes. These original species were later replaced primarily with Inga vera for uniform shade. This resulted in a bicultural production system. This was even later replaced by mono cultured full sun coffee which is not appreciated by environmentalists because of the environmental degradation in this ecological zone. Seventy percent of the crop is full sun coffee; the other thirty percent is shade coffee grown under traditional tree species such as Inga vera and Gliricidia sepium. Sun grown coffee is not sustainable because of the following reasons:
- limited returns at the farm level
- hurricanes damage in coffee plantations
- increase erosion and reduced bio-diversity
At present time limited returns at the farm level is causing a serious threat to the Coffee Industry in Puerto Rico. The Coffee Industry transitioning from a protected market to an open market is due to US trade agreements. Coffee producers are responding by attempting to produce world class coffee in order to enter gourmet and specialty markets. They are also interested in coffee shade trees that produce a higher return and are potentially as valuable as the coffee.
The coffee with the highest potential to enter international markets is the higher elevation coffee above 2,400 feet in elevation. The coffee has special conservation needs to control erosion. Traditional shade agro forestry systems are not usually acceptable as they lead to more fungus problems in this cooler environment. Alley cropping (usually on the contour) is more suited to providing the lighter shade needed in this system. Alley cropping is also an excellent method to reduce hurricane damage in coffee as alley cropping also functions as windbreaks.
The sun grown coffee has increased erosion and reduced bio-diversity. A massive destruction to our forest areas was caused by this mono cultured system; buffers zones have been destroyed. Native wood trees had been removed; some of these are threatened and endangered species. Sun grown coffee in this region requires high application levels of chemical products and fertilizers. Sediment accumulation has greatly reduced the storage capacity of the principal water-supply reservoirs in Puerto Rico.
The first objective is to measure and evaluate the seedlings based on standard criteria and tests in use in the nursery facility. These will include:
- Height, and
- Percent Survival
The second objective is to transplant at coffee farms. The seedlings also will be evaluated inside coffee crops in 3 separate farms (3 acres each) for:
- Percent Survival, and
Tables – The tables were painted with tar and gasoline homemade coating to protect them from water and fertilizer acids. The seedlings were placed on a table framework constructed of angle irons and expanded metal plate – of 1.5 inch, #9 — to hold a maximum of 640 tube containers.
Tube Containers – Stuewe & Sons Deepot cells 40 cubic inch volume, 2.5 inch diameter and 10 inch deep. Cell trays – with 1’ x 1’ dimensions — held 20 tube seedlings each on tables of 4 ft by 10 ft. Each cell can be separated individually from the tray to allow from culling and manipulation. 1,700 cells were planted; they occupied 80% of the available table space. Cells were placed on top of the expanded metal plate to allow for air pruning of the pivotal root.
Growing Medium and Seeding – Forestry industry standard – Sunshine Mix #1 — formulated with Canadian Sphagnum peat moss, coarse grade perlite, gypsum, Dolomitic lime and our long-lasting wetting agent. No replanting of germinates was done; all cells were seeded directly on the trays. The tables’ function was to facilitate labor, help drain the tree seedlings, and prevent pathogens by eliminating ground contact.
Project Relocation –After several attempts to implement this project at Mr. A. Rivera nursery we decided to move this one to Toro Negro State Forest. Water resource issue impeded us to continue with the project at this site. Therefore, we decided to start all over by replacing the growing medium and replanting new seeds collected inside the forest. The problem is described on the attached report in Appendix 1. A letter of agreement was signed by the Forest Manager ON April 7th, 2009; copy of the letter is in Appendix 5.
Just the cell trays and 1,700 tubes were moved to the Toro Negro forest. The tube seedlings were placed on a table framework constructed of galvanized pipe and plastic skids — with 1”x 2” rectangular holes — at the table surface. These tables are suitable for this kind of project allowing for good drainage and air pruning of the wood seedling tap or pivotal root.
Growing Medium – We continued to use the same growing medium: The forestry industry standard – Sunshine Mix #1 — formulated with Canadian Sphagnum peat moss, coarse grade perlite, gypsum, Dolomitic lime and our long-lasting wetting agent. Most of the wood species of Granadillo-Buchenavia capitata and Higuerillo-Vitex divaritata did not germinate mainly because the seeds were sterile by the time they were collected inside the forest. At first, either a fungus or bacteria was suspected to cause seed contamination, or probably that the seeds were inoculated by parasites to create the condition. As a result of the short-term to complete this project by the ending date of the award, it became difficult to collect new seeds and produce additional seedlings. Meanwhile, mortality rates for the 2 species were higher than expected, the use of the growing medium allowed for the expected results of this project with other 7 species included on Appendix 2.
Watering and Fertilizer – Hand watering was used to irrigate the tube seedlings with sprinkler water cans. Rainfall water was available for irrigation to avoid toxic chlorinated water serviced by Puerto Rico’s Aqueduct & Sewer Authority. This system provided a total daily water use of 3 gallons during 5 consecutive days; this is a weekly water use of 15 gallons for the 1,700 seedlings. The rate is equal to 1.2 ounces of water use per seedling. However, once the tube seedlings reached over 5 inches in height they were exposed to sunlight to allow for a vigorous plant growth. So, no irrigation was needed during rainy days. Fertilizer was a soluble 20-20-20 with trade elements at 150 parts per million. Fertilizer dosing was provided with sprinkler cans at a rate of 1.5 ounces per irrigation. Fertilization was performed twice a week.
Pest Control – In contrast to bag grown woods, there was no need to control mollusks. In contrast to bag grown woods, birds and rat control proved to be important as the seeds were disappearing from the tubes. The only effective control was the placement of a “galvanized wire mesh” on top of the tables to prevent the bird species “Margarops fuscatus” from having access to the tube cells. On the other hand, the humid environment was another important factor that needed control to prevent fungus and bacteria, and thus, seed contamination and disease during the early stages of plant growth.
A shade plastic film was used on top of the greenhouse structure to reduce moisture and also protect the tube seedlings from the exposure to heat and sunlight. Though 85 percent of Capa prieto -Cordia alliodora was infected by a fungus and currently is under recovery. We would expect a 50 percent survival by the time they are ready for transplant. On the other hand, a leaf miner caused some damage to Almendron-Prunus occidentalis at the height of 3 inches; 67 percent were somewhat affected, but no significant loss to prevent the wood tree from growing into adult. This was the only insect of any consequence to the wood species.
General – The aim of the project was to develop seedlings meeting or exceeding the criteria of success established for the current plastic bag system at the nursery and inside coffee crops. As we expected, the new system had to overcome the limitations of the old in production costs, impact on the environment, and agronomic deficiencies.
Overall, the tube container system was found to be superior to the bags in complying with the stated aims of the project. Even though, germination was not successful at the beginning of the experiment, the tube seedling health and conformation at the Toro Negro Nursery were as good as the bag trees. While the stem of the tube trees was less developed, as had been expected due to crowding, the tube products reached the same height of the bag seedlings. The predominant tree species proved to be Maga-Thespesia grandiflora), Moralón-Coccoloba pubescens and Maria-Calophyllum brasiliense ; their speed of germination and plant growth was pretty quick, up to 21, 15, and 12 inches in height respectively during the period of April 7, 2009 to September 1, 2009. Whereas, the Granadillo-Buchenavia capitata and Capa prieto-Cordia alliodora seedlings, at least the small number that achieved germination, lasted too long and grew up only from 4 to5 inches in height during this same period of time. Leaf size was not as restricted, but the caliper measurements of the trunks were smaller than hoped, though is still acceptable. Density of the roots per volume unit of growing medium was superior in the tubes.
The wood trees had been established on the coffee producing areas; 82 percent of survival was achieved at Mr. Samuel Rivera’s coffee operation unit. Some of his trees died as a result of the extended drought period of October through December 2009. Whereas, Ana Coffee Estate had 100 percent survival after 5 months of being planted inside the crop. Here, weather patterns are more favorable as this unit is located in the humid mountains of Puerto Rico, with 80 to 120 inches of rainfall throughout the year. Just a few Jacana-Pouteria multiflora exhibited a Nitrogen deficiency characterized by the appearance of a uniform yellowish color on the entire foliage. One ounce per gallon of nutrient was applied with a sprinkler water can to successfully overcome the condition within a 2 to 3 weeks period. The other farm cooperators have had similar results as their trees have been planted within the humid mountainous coffee region. Overall survival rates for this project have been quite acceptable as most of the trees have survived at the nursery and on the field. Appendix 3 illustrates photos of the tube seedlings at different stages of growth and wood trees from 12 to 30 inches in height established by the project cooperators.
On the date of the submission of this report 1090 tube seedlings were transported and planted inside the coffee crops; this is a 64 percent of the total amount of 1,700 trees that were proposed for this project. The first trees were established by the end of September 2009. In Appendix 4 we have included the agreement letters signed by farm cooperators committed to provide maintenance to the trees for the next five years period. Table 1 on next page provides detailed information concerning the wood trees distribution to project cooperators.
We are currently producing 610 tube seedlings at Toro Negro’s nursery in order to complete the total amount figure. The seeds were planted by December 2009, so we expect to have the wood trees established at the coffee producing areas by June 2010. The establishment of these trees will be made at no cost as the sub-award period of project performance ended on February 28, 2010.
Appendix 2 describes the growth rates and percent survival for the tube seedlings at the nursery and farm levels. There has been no significant increase in tree diameter as they are still at the early stages of growth. Therefore, the data has not been included in this report; we will start measuring tree diameters within the next 6 to 8 months, beginning from its first year of the growing stage.
Problem – Substantial tracts of land are needed to establish bag nurseries. This involves expenditures in constructing lots and access roads in the mountainous interior of the island, and the creation of infrastructure (irrigation, electrical, drainage, shade cloth houses) over a wide area.
Solution — Tube containers reduced planting area to one seventeenth of the bag nurseries. There is more space available inside the green house. Germination boxes were eliminated.
Problem – The bag growing media must be prepared on-site using top soil and organic materials, both which are expensive and hard to procure. Manufacture of the growing medium requires heavy equipment and special machines which must be housed in large structures.
Solution – Soil was substituted by a light weight, organic, non soil medium. As opposed to manures and composts, these materials require no government permit to process or transport.
Problem – Transportation costs within the nursery, and to and within the farms are high because the bags are fairly large and heavy. The average weight of each filled bag is 8 pounds. Its volume is 226 cubic inches. A nursery worker can only carry 7 bags, weighing 56 pounds total.
Solution – Tubes decreased container weight in a 13:1 ratio, each cell weights 10 ounces. Cell volume is 40 cubic inches each; volume decreased by a 6:1 ratio. 120 tube seedlings, enough to plant 2 acres, weight no more than 75 pounds, and can be carried in a 3ft x 2ft x 2ft in height cardboard box. The coffee producers just made a round trip to transport the tube seedlings from the nursery to their farm operation. It took nearly 3 to 4 hours to pick up the trees, and 21 hours average for a farm laborer to plant 100 trees at a rate of $7.25 per hour.
Problem – Heavy use is made of expensive agricultural chemicals because of the large area involved and because the soil in bags must be treated as well and its volume is high. As the growing medium is not sterile and the bags are placed directly on the ground the rate of application and variety of agricultural chemicals is increased.
Solution – The use of agricultural chemicals, except for soluble fertilizer, was eliminated. This was made possible by lifting the crop off the ground where many pests and pathogens are concentrated, and reducing the volume of the growing medium thereby diminishing the volume of chemicals needed to treat pests and disease found in the medium. Also, an opaque plastic film was used on the greenhouse to avoid excessive dampness and appearance of fungus during the extended periods of rainfall; this would also reduce radiant temperatures inside the structure.
Problem – The bag system is labor intensive in all phases of production. This is by far the greatest cost of production in the nurseries.
Solution – Maintenance was reduced to less than 1 hour a day, it was spent mostly on hand watering. Non maintenance operations dropped from 2 months to a few days. Handling the seedlings to coffee farmers took minutes rather than hours.
Problem –The heavy use of agricultural chemicals has been mentioned. The large areas taken up by the bag nurseries make containment of pollution difficult. Controlling runoff is not easy with the many streams present and the typical rain levels reaching 80 to 120 inches in the mountains where the nurseries are established. Puerto Rico has one of the highest population densities in the world and virtually all nurseries are located next to homes and communities, augmenting the potential for chemical harm.
Solution – Under the condition of the experiment, no chemical application was necessary. There was no special weather or other atypical situation which could account for this unexpected result, so it is felt that the result is reproducible for other tube seedling projects. The sterile growing medium prevented soil insects. Soil fungi were avoided on nearly 92 % of the seedlings through the use of sterile, aerated medium. Mollusks did not invade the seedlings because it was raised off the ground. On the other hand, the low temperatures are not favorable for their proliferation and adaptability on this Toro Negro Forest.
Problem – Conventional nurseries are wasteful of water. Ironically for such a well watered land, usable water is scarce and expensive in Puerto Rico, due to pollution, inefficient infrastructure and management. All water resources in Puerto Rico are owned by the central government and franchised to the nurseries. With the mounting pressures from a growing population, inefficient use of water in agriculture is no longer acceptable.
Solution – Because of the concentrated planting area and small container volume, the overall water use for the tubes is similar to the thriftiest system, that is, drip irrigation.
Problem – All operations within the bag nursery and seedling transportation rely heavily on the use of fossil fuels.
Solution — Cutting back on high energy operations and equipment curtailed the wasteful use of fossil fuels. Reuse and recycling of containers and trays keep the hydrocarbons spent in producing plastic in the production chain rather than in dump or in an incinerator.
Problem – The combination of germination in sand beds, replanting of germinates into the plastic bags, and the bags themselves promote the development of root abnormalities. These include L, J and spiral roots and multiple tap roots.
Solution – The root system of hundreds of tube seedlings were observed. Spiral and J roots occurred in none. Only field observations will reveal if this positive behavior will continue after transplant. Because of the high germination rate of the fresh wood seedlings, except for those which became sterile, direct seeding was a success, both from the speed at which it was carried out and from its agronomic benefits.
Problem – The soil based medium, particularly its clay component, does not provide sufficient porosity and related root aeration, leading to losses to damping-off disease in the early stages of seedling development. Soil porosity is 50%. A soil, peat, and sand mixture in equal parts has 55% porosity. Therefore, the inclusion of soil as a mayor ingredient (20 to 30%) in a container mix reduces porosity to unacceptable levels, when proper levels should be in the order of 80 to 90%.
Solution – Good results were obtained with the forestry industry standard mix — formulated with peat moss, coarse grade perlite, gypsum, Dolomitic lime and wetting agent. The results obtained with this medium so far have been encouraging.
Educational & Outreach Activities
A power point presentation was made by Agro. Rafael Rivera, president of the Specialty Coffee Association of Puerto Rico, to Council members of El Caribe Resource Conservation & Development (RC&D).
The project was featured in the annual report of El Caribe RC&D. The report was mailed to all NRCS Offices, all municipal mayor’s offices, federal and state government agencies, and most of the agricultural cooperatives in Puerto Rico.
A presentation was also made to senior management of USDA Natural Resources Conservation Service (NRCS). They are interested in basing an Environmental Quality Incentive Program (EQIP) practice on this research project. There are over 7,000 coffee producers on the island highly interested in establishing these native woods to increase their income. The EQIP practice would aim to convert these to the new system because of the soil conservation aspect and other environmental benefits particularly in reduced pesticide use and reduce irrigation water use and discharge. NRCS would like to see a follow up project done on an economic analysis of the system before implementing in a wide scale.
The project has been discussed extensively at meetings of the Specialty Coffee Association of Puerto Rico. This has resulted in a large number of farmers visiting the nursery during the production cycle.
Several meetings are planned with coffee experts from the University of Puerto Rico and Puerto Rico Department of Agriculture. Also, these are key persons that could assist with this project and will help disseminate the information.
- 2010 NRCS RC&D Annual Rpt — El Caribe SPANISH Version
- 2010 NRCS RC&D Annual Rpt ENGLISH Translated Version– El Caribe
If any chemical applications are made they should be of low toxicity, done infrequently, and directed to exposed edges of the crop. Nothing else is necessary. The absence of strong insect and fungal pressures opens the possibility to develop the wood seedlings through organic method.
An analysis of the physical properties of the available commercial mixes is proposed and some should be chosen that best strike the balance between water retention and aeration demanded by the tube grown seedling. The aim should be to achieve high percentages of successful germinations while assuring enough water retention to liquidate or reduce daily hand water.
A production schedule should be implemented that would prevent seedling distribution to farmers during the dry months of winter. Production protocols should be optimized to reach germination 4 to 8 weeks after sowing and distribute seedlings to farmers 4 to 5 months after germination. In this way 2 crops of seedlings could be produced in a year.
Addition of soil to the tube potting mix is not recommended . It impedes aeration and increases weight of the container. The purported benefits accrued from its use, such as provision of trace elements and beneficial microbial inoculation are best achieved through other means. Addition of trace elements through the fertilizer nutrient mix is cheap, while inoculants can find their way spontaneously to the wood tree from the forest and coffee producing area surrounding the nurseries.
Though our present tube container system is simple and cheap enough to be within the reach of any farmer, the savings achieved through its adoption and the pressure from future environmental regulations might make it possible and mandatory to switch to modern nursery setups. NRCS should consider the adoption of the tube seedling concept as a conservation treatment measure to address natural resource concerns, particularly those relating to soil and water.
An economic analysis was not done as part of this project. This project concentrated on refining materials and methods of wood trees production. A future work of this project needs to now address economic analysis.
Costs were only tracked in relationship to the conventional tree production in bags of native soil which is substantially more expensive.
Toro Negro’s nursery definitely plans to continue using tube containers for farmers interested in wood trees. Mr. Gerardo Hernandez, manager of the Toro Negro State Forest would recommend this system to all nursery owners and look forward to perfecting the system as previously outlined. The basic protocol that was elaborated will be maintained as it has proved positive results and practicability. The new methods will be resisted for a while by some farmers and agency officials but the same can be said for the plastic bags and any other innovation in forestry when first tried out in Puerto Rico. This seems to be part of human nature but in the end the convenience of the tube containers will win the day.
Areas needing additional study
Now that materials and methods have been refined we are ready to continue with an economic analysis.
Other formulated growing mediums need to be evaluated. We only had Forestry industry standard – Sunshine Mix #1. Clearly, a purely theoretical solution to the optimal mix problem is not possible. Trials have to be run on site with growing mixes with different water holding capacities. The best medium is the one that achieves a balance of conflicting requirements: lightness for transportation and handling, fast drainage and many air pores for damping-off prevention in germination and best growth in the first stage versus the need for augmented water holding in the last stage of growth.
Seedlings need to be monitored on the field during the next 5 years for data collection of growth rates, tree diameter, and survival.