ORIGINAL ARTICLE

 

Interrelation of indicators of management-plant health-conservation of forage resources in Cuban silvopastoral systems

 

Interrelación de indicadores del manejo-fitosanidad-conservación de recursos forrajeros en sistemas silvopastoriles cubanos

 

 

O. Alonso,^I J. C. Lezcano,^I Yohania Sanabria,^I Moraima Suris,^II

^IEstación Experimental de Pastos y Forrajes “Indio Hatuey” (EEPFIH), Central España Republicana, CP 44280. Matanzas, Cuba.
^IICentro Nacional de Sanidad Agropecuaria (CENSA), Apartado 10, San José de las Lajas. Mayabeque, Cuba.

 

 

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ABSTRACT

In order to know how some management indicators of silvopastoral systems and their plant health contribute to the duration of the main forage species that form their associations, eight silvopastoral systems were sampled (six in Matanzas province and two in Mayabeque province). The botanical composition of grasslands was measured, as well as the amount of weeds, the associated entomofauna and its functional composition. Results indicated that, having a proper management in paddocks of silvopastoral systems, in paddocks 1, 2, 4, 6 and that of double purpose (bull fattening-seed production), there was an increase of the percentage of meadow species in the botanical composition and the density of leucaena trees per hectare was maintained. A similar performance was obtained with the presence of phytophagous and beneficial insects, mainly in these last, which prevented massive outbreaks of pests during the evaluated period. In the paddocks with SSP-4, 5, 6 and 7, where the percentage of natural grasses increased, there was also an increase of the number of weeds, which is an indicator of bad management in animal husbandry, although in some cases they can be used as shelter and/or food (pollen or nectar) for predators and parasitoids, as it happened in the SSP-4 and 6. It can be concluded that management indicators (necessary rest time of the grass, animal stay and proning labors), as well as the conservation of natural enemies in the favorable environment created for them, allowed to maintain the biological balance (without massive outbreaks of pests) in the areas during the evaluated period. They also contributed to the persistence in time of the permanent forage plant resources that compose these systems (in their majority), and to their economic and environmental sustainability.

Key words: management, plant resources conservation, plant health, silvopastoral systems.

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RESUMEN

Para conocer en qué medida algunos indicadores del manejo de los sistemas silvopastoriles y su fitosanidad contribuyen a que perduren en el tiempo las principales especies forrajeras que conforman sus asociaciones, se muestrearon en un año ocho sistemas silvopastoriles seis en la provincia de Matanzas y dos en Mayabeque. Se midió la composición botánica de los pastizales, la cantidad de las arvenses presentes y de la entomofauna asociada y su composición funcional. Los resultados indican que en los cuartones de los sistemas slvopastoriles, donde hubo adecuado manejo, el 1, 2, 4, 6 y el de doble propósito (ceba de toros-producción de semillas), se incrementó el porcentaje de especies pratenses en la composición botánica y se mantuvo la densidad de árboles de leucaena por hectárea. Un comportamiento similar se obtuvo con la presencia de insectos fitófagos y benéficos, sobre todo de estos últimos, que impidieron brotes masivos de plagas en el período evaluado. En los cuartones de los SSP-4, 5, 6 y 7, donde se incrementó el porcentaje de pastos naturales, también aumentó el número de arvenses, el cual en el ámbito ganadero es un indicador de mal manejo, aunque en algunos casos sirven de refugio y/o alimentación (polen o néctar) a depredadores y parasitoides, como ocurrió quizás en los SSP-4 y 6. Se concluye que los indicadores de manejo (tiempo necesario de reposo del pasto, estancia de los animales, labor de poda), así como la conservación de los enemigos naturales en el ambiente favorable que se crea para ellos, permitieron mantener el equilibrio biológico (sin brotes masivos de plagas) en las áreas durante el período de evaluación. Contribuyeron también, notablemente, a la persistencia en el tiempo de los fitorrecursos forrajeros predominantes que componen estos sistemas (en su mayoría) y a su sostenibilidad económica y ambiental.

Palabras clave: manejo, conservación de fitorecursos, fitosanidad, sistemas silvopastoriles.

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INTRODUCTION

The introduction of plants is considered one of the plant improvement methods with better scientific connotation, and, at the same time, one of the most dynamic and economic ones, because, with its use, similar results to those of a long and expensive program of genetic improvement are achieved, during a relatively short period. In addition, it contributes to the increase and conservation of plant diversity in different agro ecosystems, which is an imminent need nowadays.

However, in situ conservation of these resources is not always strictly fulfilled. When included in livestock production systems, as is the case of silvopastoral systems, no proper management is repeatedly carried out, taking into account as many indicators as possible: pasture response to stocking rate under grazing, availability and quality of the used species, rest time, persistence of meadow and forage species in grazing, and height, time and frequency of tree cutting, among others stated by Milera et al. (2014). In addition, according to FAO reports in 2006, 90% of plant origin foods in the world are only based on 20 crops. This confirms the deficiencies in the management of plant resources (Agüero 2009), because that number should not have changed accordingly during the last years.

Therefore, the objective of this research was to know how some management indicators of silvopastoral systems (SSP) and their plant health contribute to the duration of the main forage species that form their associations in the time.

 

MATERIALS AND METHODS

Three of the four evaluated varieties of L. leucocephala coincide with those registered as commercial in Cuba, according to CNSV (2012), although, in the 2006 version, it was also considered as cultivar variety CNIA-250.

Regarding the localization of productive systems, every plantation is settled in areas and enterprises representing the Cuban livestock sector. The first three and the last, at the Experimental Station of Pastures and Forages “Indio Hatuey”, the fourth in the Livestock Enterprise (EP) Genetica de Matanzas and fifth in the EP “José Martí”, all in Matanzas province. While the sixth is located in the EP “Nazareno” and the seventh in the EP “Valle del Peru”, both in the province Mayabeque. (Table 1)

Management indicators of SSP were defoliation labors (pruning or cutting), rest time of paddocks after grazing and persistence of meadow and forage species in grazing. Pruning labors were carried out only to the 50 % of plants between 1.0 and 1.5 m during the dry season (from March to the beginning of May) in five leucaena plantations, belonging to SSP-1, 3, 5 and 6 and in the SSPDP. Pruning labors were not performed in SSP-2 and SSP-4 because there was no need of food for animals during this period. In SSP-7, it was not performed due to an improper management of the plantation, while during the rest time, it ranged between 28 to 45 d in the rainy period and from 49 to 66 in the dry period. In addition, there were neither organic or inorganic fertilization nor the application of biological and chemical products for pest control.

The measures carried out were related to the botanical composition of grasslands, the amount of present weeds and associated entomofauna, and its functional composition. The first and second measuring were performed at the begining of the experiment, and the last two during the months of higher presence of insects (March, May, October and November), determined in a previous study, carried out for three years in the SSP-1 and in SSPDP.

Botanical composition was determined by the step methods (regarding the percentage of predominant grass species) and tree density per hectare, was established using a cross multiplication (considering the length of furrows and the amount of plants within them). Weeds were determined using a frame of 1m² in five points of the field.

 Insects were quantified every 15 d, before the entrance of animals to grazing, according to Nielsen (2003), after being captured by means of an entomological net in the tree and herbaceous stratum. An amount of 100 sweeps of the net in five points of the evaluated fields were carried out, which is equivalent to 25 m², according to Faz (1990). Functional groups (phytophagous and beneficial) of insect community were defined after identifying each species. Their function was determined according to the observation and information offered in literature about their feeding habits, specifically taking into account the criteria of Ruiz and Castro (2005).

Insects, as well as weeds, were moved to the lab of plant protection from the Estación Experimental de Pastos y Forrajes “Indio Hatuey” for their identification, using taxonomical keys and the contribution of other specialists.

 

RESULTS AND DISCUSSION

According to table 2, in SSP-1, 2, 4, 6 and SSPDP paddocks, where the days of stay of animals in the paddocks and the rest time of the grass were fulfilled, there was an increase of predominant meadow species (base grass) on the botanical composition. Density of leucaena trees per hectare was maintained. In SSP-3, with similar management, there was a decrease on the percentage of base grass, as well as on density and number of leucaena trees, due to plant mortality provoked by prolonged floods, before and during the experimental period. In SSP-6, there was also a decrease of density and number of leucaena trees because they were not properly pruned according to the established parameters. In SSP-7, trees increased because pruning labors were not performed and animals did not properly rotated due to problems with the fence. This contributed to the development of the invasive characteristic of leucaena, as it has been called by several botanists in Cuba and abroad.

Insects (table 3), in a general sense, had a similar performance regarding the increase of species in paddocks, which were properly managed, mainly in SSP-1, SSP-4 and SSPDP, where predators and parasites prevented massive outbreaks of pests during the evaluated period. In SSP-5, 6 and 7, there could be an increase due to the high amount of weeds that appeared there, used as shelter and/or food (pollen or nectar for adults) for these beneficial  agents (Altieri and Nicholls 2007).

Among the insects that appeared in all the sampled areas, there was an unidentified parasitic tachinid, Wasmamnia auropunctata (Roger) predator and the phytophagous from Hemiptera order: Heteropsylla cubana Crawford (Psyllidae), Empoasca sp. (Cicadellidae) and Rhinacloa sp. (Miridae). Out of these, the Psyllidae was considered as the most important pest at global level, according to Shelton (1996), and in Cuba, regarding the statements of Barrientos et al. (1991), who stated that it can produce up to 95% of damage in the apical portion of the branches.

It is also important to state that paddocks of SSP 4, 5, 6 and 7, where the percentage of natural grasses increased, contained the highest number of weeds, which are indicators of bad management in the livestock field, according to Milera et al. (2014). Therefore, in a general sense, they could influence on the decrease of predominant grasses, mainly on herbaceous grasses, like in the second and last systems, which were previously mentioned. The most abundant weeds of the sampled areas (except SSP-1 and SSPDP) were Mimosa pudica L. (Mimosaceae) and Sida rhombifolia L. (Malvaceae), followed by Dychrosta chiscinerea (L.) Wight & Arn. (Mimosaceae), which are native from Cuban grasslands, according to reports from the livestock field in the country.

Results of this experiment coincide with studies on SSP by other authors, who pointed out that these systems have demonstrated their importance to conservation of plant resources and associated fauna (Wick et al. 2000 and Ramírez and Enríquez 2003), always with a proper management of these resources.

It can be concluded that management indicators (necessary rest time of the grass, stay of animals and pruning labors), as well as the conservation of the natural enemies in a favorable environment created for them in these systems, and it allowed to maintain the biological balance (without massive pest outbreaks) in the areas during the evaluation period, had a remarkable contribution to the persistence of predominant forage plant resources that (mostly) compose these systems, and, therefore, to the tendency to an economical and environmental sustainability.

 

REFERENCES

Agüero, T. 2009. La importancia de los recursos genéticos vegetales y animales en el desafío de convertir a Chile en una potencia alimentaria y forestal. Santiago de Chile, Chile: Gobierno de Chile-Ministerio de la Agricultura-Oficina de Estudios y Políticas Agrarias (ODEPA), 5 p.

Altieri, M. A. & Nicholls, C. I. 2007. Biodiversidad y manejo de plagas en agroecosistemas. (ser. Perspectivas agroecológicas, no. ser. 2), Barcelona: Icaria Editorial, 245 p.

Barrientos, A., Ruiz, T. E., Febles, E., Castillo, E. & Mora, C. 1991. “A note on the utilization of three insecticides for the control of Heteropsylla cubana Crowfort (Hom: Chermidae) in Leucaena leucocephala”. Cuban Journal of Agricultural Science, 25 (2): 207–209.

CNSV 2012. Lista oficial de variedades comerciales. Registro de variedades comerciales de certificación de semillas. La Habana, Cuba: Ministerio de la Agricultura/Centro Nacional de Sanidad Vegetal, 30 p.

Faz, A. B. 1990. Principios de protección de plantas. 2nd ed., Ciudad de La Habana, Cuba: Ciencia y Técnica, 601 p.

Hernández, A., Ascanio, M., Cabrera, A., Morales, M., Medina, N. & Rivero, L. 2003. Nuevos aportes a la clasificación genética de suelos en el ámbito nacional e internacional. La Habana, Cuba: AGRINFOR, 145 p.

Milera, M. de la C., López, O. & Alonso, O. 2014. “Principios generados a partir de la evolución del manejo en pastoreo para la producción de leche bovina en Cuba”. Pastos y Forrajes, 37 (4): 382–391.

Ramírez, M. & Enriquez, M. L. 2003. “Importance and diversity of ants in silvopastoral systems in the Cauca Valley, Colombia”. Livestock Research for Rural Development, 15 (1): 1–12.

Ruiz, L. & Castro, A. E. 2005. “Riqueza y distribución de grupos funcionales de insectos en parcelas de maíz en Los Altos de Chiapas”. In: González M., Ramírez N. & Ruiz L., Diversidad biológica en Chiapas, México: Plaza y Valdés S.A., p. 441.

Shelton, H. M. 1996. “El género Leucaena y su potencial para los trópicos”. In: Clavero T. (ed.), Leguminosas forrajeras arbóreas en la agricultura tropical, Maracaibo, Venezuela: Centro de Transferencia de Tecnología en Pastos y Forrajes, Universidad del Zulia, p. 17.

Wick, B., Tiessen, H. & Menezes, R. S. 2000. “Land quality changes following the conversion of the natural vegetation into silvo-pastoral systems in semi-arid NE Brazil”. Plant and soil, 222 (1-2): 59–70.

 

 

Received: November 26, 2015
Accepted: February 5, 2016

 

 

O. Alonso, Estación Experimental de Pastos y Forrajes “Indio Hatuey” (EEPFIH), Central España Republicana, CP 44280. Matanzas, Cuba. Email: [e-mail]