Weed management alternatives for organic coffee agroforestry systems of Puerto Rico

Final Report for LS10-231

Project Type: Research and Education
Funds awarded in 2010: $150,000.00
Projected End Date: 12/31/2014
Region: Southern
State: Puerto Rico
Principal Investigator:
Mariangie Ramos
University of Puerto Rico at Utuado
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Project Information

Abstract:

A comparison of different organic weed management practices in organic coffee agroforestry systems (CAFS) provided insight into the effectiveness of organic weed management practices at both suppressing weeds and conserving the natural resources of coffee farms. Although it required more labor time, the use of cover crops was more effective in suppressing weeds than mechanical and natural herbicide treatments. The provision of ecosystem services (i.e. soil conservation, natural pest control and nematode diversity conservation) did not differ between organic weed management treatments. Most farmers surveyed in results workshops had positive opinions of the cover crops evaluated.

Project Objectives:

1) Evaluate the effectiveness of different organic weed management practices in established organic coffee agroforestry systems (CAFS) and coffee farms transitioning to organic CAFS.

2) Determine the effect of different organic weed management practices on labor time and coffee production.

3) Determine the effect of different organic weed management practices on the ecosystem service of soil conservation.

4) Determine the effect of different organic weed management practices on the ecosystem service of natural pest control.

5) Determine the effect of different organic weed management practices on the ecosystem service of soil nematode diversity conservation.

6) Evaluate farmers’ perceptions of different organic weed management practices.

7) Develop guidelines for weed management in organic coffee farms.

Introduction:

     The purpose of this interdisciplinary project was to investigate and develop sustainable weed management strategies for coffee farmers that currently follow organic methods or for those interested in transitioning to organic coffee production. Weed management is one of the biggest constraints faced by coffee farmers interested in transitioning to organic coffee production. In order to develop sustainable weed management strategies, research efforts must consider: a) the effectiveness of different weed management practices in the region, b) the compliance of practices with USDA National Organic Program standards, c) the effect of weed management practices on the natural resource base, and d) the perceptions of farmers of weed management practices.
     Several groups have expressed their interest in increasing local organic coffee production, as an alternative for limited-income farmers to cope with current production constraints. In North America, organic coffee sales are increasing, showing a 32% annual average growth rate, compared to the steady 1.5% growth of conventional coffee (Giovannucci 2008). Coffee farmers in Puerto Rico and the US Virgin Islands could benefit economically by producing organically both for local and international markets. Locally, a funded SSARE project identified the potential of selling organic products to the tourism industry (Project number LS04-163). Also, in Puerto Rico, there is a strong interest to buy organic coffee by consumers and supermarkets, but there is not enough supply (E. Alvarado, personal communication). Internationally, exporter associations have identified buyers in Japan that are interested in buying organic coffee from Puerto Rico (J. Ledesma, personal communication).
     In order to produce organically, coffee producers will need organic management guidelines that are suitable for the socioeconomic and biophysical conditions of Puerto Rico. Farmers interested in transitioning to organic agriculture may face many challenges during the conversion process, including limited knowledge of organic agriculture management practices, initial lower yields, and no premium prices for three years (Katsvairo et al. 2007). Weed management has been identified as one of the major constraints to organic agriculture, both factual and perceived by farmers (Davis et al. 2008). Based on preliminary work with coffee farmers of the region, we had observed that one of the main constraints to organic coffee production will be weed management, as farmers rely heavily on herbicides and sometimes do not have shade trees. The shade and leaf litter produced by shade trees may reduce the abundance of weeds in coffee farms (Nestel and Altieri 1992). Weeds can be detrimental for crops, reducing yields and quality of products. In coffee agroforestry systems, weeds compete with coffee plants, causing a reduction in stem diameter and primary branch growth (Friessleben et al. 1991), and yield reductions might reach up to 60% (Pereira and Jones 1954). The effect of weeds on coffee yield is significant during the first year of plantation establishment, but decreases as coffee trees and shade trees grow (Aguilar et al. 2003). Weeds can also interfere with coffee berry borer, Hypothenemus hampei, management, as they may limit the ability to collect infected coffee berries from the ground. In other coffee growing regions, weeds are mainly managed through mechanical control in organic systems, which is labor intensive and too costly for farmers of Puerto Rico.
     The USDA National Organic Program (NOP) states that management practices in certified organic production should “foster the cycling of resources, promote ecological balance, and conserve biodiversity” (NOP Final Rule Subpart A 205.2). Hence, the study of organic management practices should always consider the impact of practices in relevant ecosystem services. For example, crop rotation and the use of cover crops are listed (NOP Final Rule Subpart B 205.206) as practices that must be followed in organic production operations in order to prevent weeds, but also as a way to mange soil nutrients, erosion control, and pests in general. The proposed project will evaluate weed management practices that comply with NOP, and how these practices may affect important ecosystem services that are considered in NOP, including soil conservation, natural pest control and biodiversity conservation.
     Our project evaluated four weed management alternatives for organic coffee agroforestry systems (i.e. coffee farming system that grows coffee plants under the shade of trees). To consider the sustainability of the four weed management practices, our project evaluated their weed control potential, labor time, and how they affect relevant ecosystem services (i.e. “conditions and processes through which ecosystems sustain and fulfill human life”, Daily 1997). Weed management practices are relevant to the ecosystem services. of soil conservation, nematode diversity conservation and natural pest control of coffee agroforestry systems. First, weed management practices affect soil and water conservation by affecting erosion rates. Herbaceous plants can cover the soil surface of coffee agroforestry systems, thus protecting it from rain erosivity and runoff (Perez-Nieto et al. 2005, Ataroff and Monasterio 1997). Erosion control also contributes indirectly to water quality by reducing the amount of sediment, agricultural chemicals and other materials carried by runoff to water reservoirs (Dale and Polasky 2007). Secondly, weed management practices affect nematode communities of coffee agroforestry systems by suppressing or enhancing parasitic or free-living nematodes (Herrera and Marban-Mendoza 1999). Nematodes play a significant role in the decomposition of soil organic matter, mineralization of plant nutrients, and nutrient cycling, and serve as indicators of the ecological condition of soils (Neher 2001). Lastly, weed management practices affect the natural control of pests indirectly by affecting the weed plants that serve as hosts for arthropods (Norris and Kogan 2005). Weeds provide resources for natural enemies of insect pests, like floral rewards for parasitoids (e.g. Damon et al. 1999) and alternative prey for predators (e.g. Lykouressis et al. 2008).

Cooperators

Click linked name(s) to expand
  • Edgardo Alvarado
  • Marisol Davila
  • Olgaly Ramos Rodriguez
  • Yaniria Sanchez

Research

Materials and methods:

Study Site

    The study was conducted at two sites within the central mountain region of Puerto Rico, in the municipalities of Utuado and Orocovis. The Utuado site is a former conventional coffee plantation transitioning to organic agroforestry management, and the Orocovis site is an established organic coffee agroforestry system. The Utuado site is the coffee farm of the University of Puerto Rico at Utuado. Since September 2008, this farm started a transition process to organic agroforestry management, planting Inga species as shade trees and pigeon pea (Cajanus cajans) as temporary shade. The Orocovis site is a private organic family farm. The owner, Edgardo Alvarado, and his family have been producing organically since Mr. Alvarado was a child. Shade trees are approximately thirty years old (E. Alvarado personal communication) and are mainly Inga species, although some fruit trees and banana plants are also present.

Weed management experiment

     An experiment that evaluated the effectiveness of different organic weed management practices was conducted independently at the two sites. The experiment followed a completely randomized design with four repetitions (= four blocks). The plots measured 12 m2 (6 m x 2 m). The size of plots was chosen based on previous soil erosion studies in coffee farms (Ataroff and Monasterio 1997).
    At the Utuado site, the experiment was conducted from June 2011 to February 2013. Four organic weed management treatments were evaluated at Utuado. These were: a) mechanical control with a trimmer, b) OMRI-listed herbicide, c) cover cropping with Arachis pintoi, and d) cover cropping with Heterotis rotundifolia. A control with no weed management was established for comparison (for a total of five treatments). Twenty plots (5 treatments x 4 repetitions) were established, and one of the five treatments was assigned randomly to each. Weed management treatments were applied at the beginning of the experiment and re-applied as needed when weeds grew over 20 cm high. In all plots, vegetation was removed around the base of the coffee plants. The mechanical control treatment was applied with a semi-industrial trimmer. The OMRI-listed herbicide treatment was applied as indicated by the product label with a back sprayer. For the Arachis pintoi and Heterotis rotundifolia cover crop treatments, all weeds were removed from the plot using a hoe. Then, cover plants were planted following a triangle spacing arrangement with a distance of 45cm between plants. Both cover crop species were propagated from cuttings and grew in the nursery in 4 inches pots.
     At the Orocovis site, the experiment was conducted from July 2011 to November 2012. Three organic weed management treatments were evaluated at Orocovis. These were: a) mechanical control with machete, b) OMRI-listed herbicide, and c) cover cropping with Arachis pintoi. The Heterotis rotundifolia cover crop treatment was not evaluated, since the farm owner had concerns over the plant becoming a weed. A control with no weed management was established for comparison (for a total of four treatments). Sixteen plots (4 treatments x 4 repetitions) were established, and one of the four treatments was assigned randomly to each. Weed management treatments were applied at the beginning of the experiment. The mechanical control treatment was applied with a machete. The OMRI-listed herbicide treatment was applied as indicated by the product label with a back sprayer. For the Arachis pintoi cover crop treatment, all weeds were removed from the plot by hand. Then, A. pintoi plants were planted following a triangle spacing arrangement with a distance of 45cm between plants. Arachis pintoi was propagated from cuttings and grew in the nursery in 4 inches pots.

Variables evaluated in the experiment

Weed biomass

     To evaluate which weed management treatment suppressed weeds more effectively, all weeds within one randomly placed 0.25 m2 quadrat were cut at ground level, placed in bags and taken to the laboratory. Collected plants were oven-dried at 60°C for 48 hours. Total weed biomass were compared among weed management treatments using a one-way ANOVA statistical analysis. At the Utuado site, above ground dry weed biomass was recorded in each plot before treatment application and re-applications. At the Orocovis site, above ground dry weed biomass was recorded in each plot four times after treatment application (2, 4, 6 and 9 months after).

Labor time

     The time it took one person to apply and re-apply weed management treatments was evaluated in each experimental plot. To record labor time, the total time it took to apply weed management treatments in each plot was measured with a chronometer. Total labor time was compared among weed management treatments using a one-way ANOVA statistical analysis.

Brix

     The sugar content (Brix) of coffee plants was measured as an indicator of coffee plant status, as coffee production could not be evaluated. In each plot, two leaves were collected from the middle section of five coffee plants. The sap of leaves was extracted by adding 10mL of distilled water and macerating the leaves of each plot in a mortar. Then, the Brix was measured using a refractometer. This was done before treatment applications and twice after (2 months and 12 months later).

Soil conservation

     To determine the effect of different organic weed management practices on the ecosystem service of soil conservation, soil erosion and soil nutrient status was examined in each of the experimental plots described above. Soil erosion was measured directly by following the methodology developed by Ataroff and Monasterio (1997). A trap channel and a sediment collector were established at the bottom of the plot to measure runoff and eroded soil from each plot. An automatic rain gauge was installed to measure rainfall at each study site. These data was collected continuously throughout the experiment. Runoff and soil loss were compared among treatments. 
     A basic soil characterization was performed, and soil nutrient status and soil water content were measured in each experimental plot described above, before treatment application and at the end of the experiment. Soil pH, organic matter (OM), available phosphorus (P), exchangeable potassium (K), exchangeable calcium (Ca), exchangeable magnesium (Mg), cation exchange capacity (CEC) and bulk density were determined for soil samples collected at the 0-5cm and 10-15 cm depths. Except for bulk density, soil samples for the characterization analyses were sent to a commercial laboratory (A&L Eastern Laboratories, Inc., Richmond, VA). Soil bulk density was measured following the core method described by Grossman and Reinsch (2002). All soil response variables were compared among weed management treatments using a one-way ANOVA statistical analysis.

Arthropod communities

     To determine the effect of different organic weed management practices on the ecosystem service of natural pest control, the abundance of predatory arthropods, coffee pests and coffee leafminer damage was evaluated in each experimental plot described above. The abundance of predatory arthropods was examined using pitfall traps. One pitfall trap was placed in the center of each experimental plot. The traps were half-filled with ethylene glycol and left in the field for a week. Predatory arthropods collected in traps were taken to the laboratory for identification and counting. Predatory arthropods were collected before weed treatment application and five times after. The abundance of the coffee berry borer was examined by means of alcohol traps before treatment application and four times after. One alcohol trap was placed in the center of each experimental plot and collected a week later. The number of coffee berry borer for each trap was recorded. Coffee leafminer damage was evaluated by counting the number of healthy and damaged leaves in four branches (one in each cardinal direction) from the middle section of a coffee plant within each plot. Abundance of predatory arthropods and coffee pests were compared among weed management treatments using a one-way ANOVA statistical analysis.

Soil nematode communities

     To determine the effect of different organic weed management practices on the ecosystem service of soil nematode diversity conservation, soil nematodes were sampled before weed management treatment application and at the end of the experiment. Five soil cores were collected randomly across a zig-zag path within each experimental plot, using a 2.5 cm-diameter cone-shaped sampling tube. These four soil cores were then mixed to form a single soil sample per plot. From this soil sample, a fixed volume of 100 cm3 of soil was processed for soil nematode extraction. Nematodes were extracted by the centrifugal-flotation method (Jenkins, 1964). Nematodes were identified to genus and counted using an inverted microscope. Nematodes were classified as plant feeders, hyphal feeders,  bacteriovores, omnivores and predators.  Nematode abundance and richness were compared among weed management treatments using a one-way ANOVA statistical analysis.

Farmers’ perceptions

     To evaluate farmers’ perceptions of different organic weed management practices, a workshop was held at UPR-Utuado on April 19, 2013. First, farmers were asked to answer a pre-workshop survey that asked about their current weed management practices and perceptions about different organic weed management practices. Research results were then presented to farmers, followed by a visit to the UPR-Utuado study site. After lunch, (provided by UPRU), farmers were divided in groups, and were asked to list strengths and weaknesses for each weed management practice studied. After, all groups presented their results to the audience, and a group discussion followed. A post-workshop survey was given to participants to ask again about their knowledge and perceptions of the different weed management practices explored in the workshop.

Training activities

     Training activities of the project included: 1) a results workshop, 2) an organic weed management manual for coffee agroforestry systems, 3) an educational video, and 4) six workshops to distribute the manual and the video among coffee farmers. The results workshop is described in the section above. An illustrative organic weed management manual for coffee agroforestry systems was developed based on project results and literature review. The manual underlines the differences between weeds and herbaceous cover plants, introduces the concept of ecosystem services and presents various organic weed management alternatives. The manual is in Spanish and can be accessed on: https://drive.google.com/a/upr.edu/file/d/0ByBoB4oi017eNVBSTHY5NmpPTXc/view. The educational video summarizes project results and topics covered in the manual. It is in Spanish with English subtitles. The video can be found on YouTube: https://www.youtube.com/watch?v=79SsNoVLrnw. The video and printed copies of the manual were distributed in six workshops held in six municipalities within the coffee producing region of Puerto Rico (Las Marias, Maricao, Jayuya, Yauco, Utuado and Orocovis). The workshops were coordinated with different organizations (Cafiescencia, Agricultores Unidos del Centro, Organizacion Boricua and Puerto Rican Society of Ornithology) and coffee farmers. Workshops were advertised through email, Facebook, local radio shows, and phone calls.

Research results and discussion:

Organic weed management effectiveness

     At the UPR-Utuado site, treatments had a significant effect on weed biomass (p<0.0001). The two cover crop treatments (Heterotis rotundifolia and Arachis pintoi) had significantly less weed biomass (mean = 6.08g and 7.27g, respectively) than the trimmer (mean = 28.95g), OMRI-listed herbicide (mean = 34.51g), and control treatments (mean = 92.25g). The OMRI-listed herbicide and trimmer treatments had significantly less weed biomass than the control treatment. The UPR-Utuado study site is a coffee farm transitioning to become an organic coffee agroforestry system. Shade trees were young during the experiment (less than two years old) and do not provide substantial shade cover. Weed biomass values were higher at this site, and weed communities were dominated by grasses.
     At the Orocovis site, treatments did not have a significant effect on weed biomass (p=0.44). The Orocovis study site is an established organic coffee agroforestry system with mature shade trees. Weed biomass values were lower at this site. Weed communities were dominated by vines and leaf litter was abundant. Cover crops treatments did not successfully establish due to shade conditions

Labor time for organic weed management

     At the UPR-Utuado site, treatment had a significant effect on weed management labor time (p<0.0001). The two cover crop treatments (Heterotis rotundifolia and Arachis pintoi) required significantly more labor time (mean = 11 and 13 minutes, respectively) than the trimmer (mean = 4 minutes), and control treatments (mean = 2 minutes). Sampling date also had an effect on labor time (p<0.0001). Even though the two cover crop treatments required more labor time during the first three months of the experiment, labor time for these treatments was reduced after cover crop establishment.
     At the Orocovis site, treatment had an effect on weed management labor time (p=0.0104). The cover crop treatment (Arachis pintoi) required significantly more labor time (mean = 5 minutes) than the control treatment (mean = 0 minutes). The Heterotis rotundifolia cover crop was not evaluated at the Orocovis site, as the farm owner had concerns over the plant becoming a weed. Sampling date also had an effect on labor time (p=0.0043). Labor time was higher for the cover crop treatment during the first month of the experiment, but after this period, it was similar to the other treatments.

Coffee plant health

     Treatment did not have a significant effect on coffee leaf sugar content at the UPR-Utuado site (p=0.21), or at at the Orocovis site (p=0.95). At the UPR-Utuado site, treatment did not have a significant effect on coffee leafminer leaf damage (p=0.13), but sampling date did (<0.0001). At the Orocovis site, coffee leafminer damage was not observed. Treatment did not have a significant effect on coffee berry borer abundance at the UPR-Utuado site (p=0.19), or at at the Orocovis site (p=0.93). However, there was an effect of sampling date (p<0.0001) and block (p<0.0001) at the UPR-Utuado site.

Ecosystem services: Soil conservation

Soil erosion 
     At UPR-Utuado site, overall soil erosion for the treatments was: 0.026 g/m2/day for the control, 0.013 g/m2/day for the organic herbicide, 0.044 g/m2/day for the mechanical (trimmer), 0.017g/m2/day for the cover crop A. pintoi and 0.061 g/m2/day for the cover crop Heterotis rotundifolia.  Repeated measures ANOVA on soil eroded data showed no treatment effect (p = 0.06) and no time effect (p = 0.20) at the UPR-Utuado site.  No consistent pattern was found in soil eroded with time. However, our data showed a trend that A. pintoi and herbicide treatments had lower soil eroded values throughout the year measured, however control, mechanical and H. rotundifolia treatments showed more variability with time. At the Orocovis site, overall soil erosion for the treatments was: 0.020 g/m2/day for the control, 0.019 g/m2/day for the organic herbicide, 0.023 g/m2/day for the manual (machete) and 0.014g/m2/day for the cover crop Arachis pintoi.  Repeated measures ANOVA on soil eroded showed no treatment effect (p = 0.38), however there was a time effect (p = 0.005) at the Orocovis site.  All treatments showed a consistent increase in soil eroded with time.  For February 2012, soil eroded ranged from 0.002 g/m2/day to 0.012g/m2/day while in June 2012 soil eroded values ranged from 0.026g/m2/day to 0.033g/m2/day.

Water runoff
     At UPR-Utuado site, overall water runoff for the treatments was: 156 ml/m2/day for the control, 165 ml/m2/day for the organic herbicide, 160 ml/m2/day for the mechanical (trimmer), 135ml/m2/day for the cover crop A.pintoi and 195 ml/m2/day for the cover crop Heterotis rotundifolia. Statistical analysis using repeated measures ANOVA on water runoff data showed treatment effect (p = 0.04) and significant time effect (p < 0.001).The A. pintoi treatment showed lower measurements of water runoff than the rest of the treatments.  In addition, water runoff followed changes in precipitation corresponding with high or low precipitation seasons.

Soil nutrient status 
     Summarized results for the variables of bulk density, soil pH, cation exchange capacity (CEC), organic matter (OM), available phosphorus (P), exchangeable potassium (K), exchangeable calcium (Ca), exchangeable magnesium (Mg) among organic weed management treatments measured are presented. Bulk density was used to calculate nutrients from mass units (ppm or percent) into of mass per volume units (mg nutrient / cm3soil).  At Utuado, no treatment effects were found for any of the variables measured, however a block effect was found for P, Ca, Mg. Overall mean pH was 5.2 from 0-5 cm depth and 4.6 from 5-15 cm depth. Overall mean CEC was 7.2 meq/100g from 0-5cm and 4.4 meq/100g from 5-15cm.  Overall mean organic matter was 42.2 mg/cm3 from 0-5cm and 29.8 mg/cm3 from 5-15cm.  Mean nutrient values for the 0-5cm were: 0.02 mg/cm3 for P, 0.14 mg/cm3 for K, 0.82 mg/cm3 for Ca and 0.09 mg/cm3 for Mg.  Mean nutrient values for the 5-15 cm depth were: 0.01 mg/cm3 for P, 0.07 mg/cm3 for K, 0.46 mg/cm3 for Ca and 0.05 mg/cm3 for Mg.  At Orocovis, no treatment effects were found for any of the variables measured, however block effect was found for bulk density, OM, CEC, P, K, Ca, Mg.  Overall mean pH was 5.0 from 0-5 cm and 4.9 from 5-15 cm. Overall mean CEC was 25.0 meq/100g from 0-5cm and 22.2 meq/100g from 5-15cm.  Overall mean organic matter was 39.1 mg/cm3 from 0-5cm and 30.0 mg/cm3 from 5-15cm.  Mean nutrient values for the 0-5cm depth were: > 0.01 mg/cm3 for P, 0.06 mg/cm3 for K, 1.51 mg/cm3 for Ca and 0.44 mg/cm3 for Mg.  Mean nutrient values for the 5-15 cm depth were: > 0.01 mg/cm3 for P, 0.05 mg/cm3 for K, 1.78 mg/cm3 for Ca and 0.53 mg/cm3 for Mg. 
     No difference among treatments may suggest that either there is no influence of experimental organic weed management practices in the nutrient status of soil, or that treatments have not been established long enough in order to cause statistically significant differences. Block effect may indicate that other factors not measured in this study, such small differences in topography, are influencing these nutrients in soil.  Data suggest that, in a 2-year period, there was no difference in nutrient status due to the organic treatments and that introducing cover crops do not represent a competitive threat to coffee plants in the short term.  It should be noted that the control, herbicide and mechanical treatments did not eliminate other herbaceous plants.  Thus, it may require to completely eliminating other plants to detect changes in nutrient status.  However, eliminating all herbaceous cover may increase erosion rates, thus losing nutrients by physical removal rather than by competition. 

Ecosystem services: Soil nematode biodiversity conservation

     At Utuado, a total of 28 soil nematode genera were found. The community of nematodes at UPR-Utuado site was dominated by plant feeders followed by bacterial feeders before and after the establishment of weed management treatments. At Orocovis, a total of 34 soil nematode genera were found. The community of nematodes at Orocovis site was also dominated by plant feeders followed by bacterial feeders. In agricultural soils, plant-parasitic groups and bacterivorous are generally more abundant trophic groups than fungivorous, omnivorous and predators.  Many plant parasitic nematodes have a broad spectrum host and feed on weed roots. Both sites were established coffee plantations with different weeds and wild plants. Also, control, herbicide and mechanical treatments, did not eliminate all the weeds present and their root system could be parasitized by plant feeders trophic group. The leguminous cover crop treatment could increase different types of bacteria that colonize the rizosphere, providing an enlarged food-base for bacterial feeders.
     At Utuado, no significant differences in total abundance, nor in species richness of nematodes were observed among weed management treatments (p= 0.3940; 0.5759). These results may suggest that, a year period is not enough time to find significant differences because treatments have not been established long enough or that organic weed management practices had no effect in total abundance or species richness.   However, Principal Components Analyses showed an association of omnivore nematode genera to the Heterotis rotundifolia treatment at the UPR-Utuado site. Although an explanation for this association was not found on the revised literature, is possible that the rizosphere of H. rotundifolia can be colonized by some omnivorous nematodes or provide adequate environment for the development of organisms, including other nematodes, that are food for omnivorous nematodes.
     At Orocovis, no significant differences were observed in total abundance, nor in species richness of nematodes among weed management treatments (p=0.8682; 0.9900). However, nematode total abundance was significantly different between pre and post treatment samples. Since nematode abundance was dominated by plant feeders, the removal of weeds and their root system potentially affected nematode abundance.

Ecosystem services: ground-dwelling predatory arthropods

            Predatory arthropod communities were dominated by ants, spiders, harvestmen, and rove beetles. Treatment did not have a significant effect on predatory arthropod total abundance at the UPR-Utuado site (p=0.1226), or at the Orocovis site (p=0.0872). At Utuado, spider abundance was affected by treatment (p=0.0315), being more abundant in the control treatment than in all other treatments.

Farmers’ perceptions of weed management practices

     More than one hundred participants from 26 municipalities attended the project results workshop held on April 19, 2013 at UPR-Utuado (only 96 participants signed the attendance register). Fifty-six participants completed the pre-survey and thirty-six the post-survey.  Pre and post survey results did not indicate statistically significant changes in respondent’s self-reported levels of knowledge regarding soil, weed and insect management, nor in their endorsement of sustainable agriculture values. However, 100% of post-survey respondents expressed that they had learned from the workshop. All post-survey respondents had positive opinions (eg. soil conservation properties, esthetic beauty, habitat for beneficial insects) about the use of Arachis pintoi as a cover crop. Most respondents also had positive opinions about H. rotundifolia, except one respondent that expressed that it could become a weed. Thirty-seven percent of respondents had negative opinions of the use of the trimmer, indicating that it could be dangerous, polluting and expensive. However, 63% of respondents indicated that it is the most effective practice to control weeds.

Training activities

     A total of 130 participants attended the six workshops in which the educational video and printed copies of the manual were presented. Forty six participants completed the post-workshop satisfaction survey. All participants that completed the survey stated that the manual and the video were very useful to them, and that they will recommend them to other farmers. Also, self-reported knowledge of cover crops significantly increased. The manual and video will continue to be available through the web after the project ends.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

A. Completed Publications

1) Ramos, M., Y. Sanchez and M. Davila. 2014. Manejo de Malezas en Cafetales Orgánicos. UPR-Utuado, Utuado, PR. Available online: https://drive.google.com/a/upr.edu/file/d/0ByBoB4oi017eNVBSTHY5NmpPTXc/view.

2) Ramos, M., J.M. Pagan, Y. Sanchez and M. Davila. Nov. 27, 2014. Manejo de Malezas en el Cafetal Orgánico . Retrieved from https://www.youtube.com/watch?v=79SsNoVLrnw&feature=youtu.be

B. Publications In Progress

1) Ramos, M., Y. Sanchez and M. Davila. In progress. Effectiveness of weed management practices in organic coffee farms.

2) Ramos, M., Y. Sanchez and M. Davila. In progress. Coffee farmers perceptions of cover crops use for weed management.

 
C. Oral and poster presentations

1) Ramos, M., Y. Sanchez and M. Davila. 2013. Servicios ecosistémicos y manejo de malezas en cafetales orgánicos de Puerto Rico. 4th SOCLA Congress, Lima Peru, September 10-12, 2013.

2) Davila, M., M. Ramos and Y. Sanchez. 2013. Weed management and soil nematode diversity conservation in organic coffee plantations of Puerto Rico. ONTA XLV Annual Meeting, La Serena, Chile, October 20-25, 2013.

3) Ramos, M., Y. Sanchez, M. Davila and O. Ramos. 2014. Management alternatives for organic coffee production. MOSES Research Forum, La Crosse, Wisconsin, February 27-March 1st, 2014.

4) Y. Sanchez, M. Ramos and M. Davila. 2014. Organic weed management and ecosystem services in coffee farms. 6th Agroecology Congress, Utuado, Puerto Rico.

 
D. Education and outreach events and field days.

1) Results workshop (included field day) – UPR-Utuado, April 19, 2013

2) Six workshops to distribute manual and video – six municipalities, from June 18-July 15, 2014.

3) Pest management in organic coffee farms workshop – UPR-Utuado, October 28, 2011.

4) Pest management in organic coffee farms workshop – El Guaraguao Coffee Farm, Orocovis, April 9, 2011.

5) Three Agroecology UPR-Mayaguez graduate course field visits – UPR-Utuado, September 20, 2013/ November 16, 2012/ October 3, 2011.

6) Field visits from Introduction to Pest Management UPR-Utuado undergraduate course – UPR-Utuado, once every semester from Fall semester 2011-present.

Project Outcomes

Project outcomes:

The project has had the following demonstrable impacts to date:

A. Changes in knowledge

1) Increased knowledge of organic weed management practices.

2) Increased knowledge of organic coffee farming.

3) Increased knowledge of the use of A. pintoi and H. rotundifolia as cover crops to repress weed growth.

4) Increased knowledge of ecosystem services and practices that conserve them in farms.

 
B. Changes in conditions

1) Organic and transitioning coffee farmers have more weed management alternatives to choose from.

2) Farmers can visit the UPRU coffee farm to see the effectiveness of cover crops for weed suppression.

3) Farmers can access the video or manual online to learn more about organic weed management alternatives.

 

The project can have the following demonstrable impacts to date demonstrable impacts in the future:

1) A higher number of farmers start producing organic coffee.

2) A higher number of farmers use cover crops in their farms.

Farmer Adoption

     Project results indicated that the use of cover crops A. pintoi and H. rotundifolia effectively suppress weeds in farms transitioning to organic agroforestry systems. However, the establishment of the cover crop can be labor intensive the first three months. Based on our results and post-experiment experience (we maintained the cover crops in the UPRU coffee farm), we would recommend the use of cover crops while shade trees grow. Once shade trees grow, shade conditions and leaf litter will suppress weed growth.
     The approximate number of participants reached to date through publications and workshops is 226. The educational video and manual online will be available online after the project ends, and will continue to impact interested groups. At the results workshop, all but one participant said in the post-workshop survey that they will start to use cover crops in their farms. To date, we have had only one testimonial from a farmer that is currently using H. rotundifolia with success.

Recommendations:

Areas needing additional study

     Future research will need to evaluate different ways to establish the cover crops that will reduce the labor intensity of the first three months. Also, long term studies should evaluate the effect of the cover crops on coffee production and farm economics. Several interested farmers could have demonstration plots in their farms to evaluate, from a farmer’s perspective, the value of cover crops for organic coffee production. Workshop participants mentioned that more training on propagating and establishing cover crops will be useful for them, in addition to being able to buy cover crops from local plant nurseries.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.