Ecological practices in Agave tequilana Weber under two agricultural systems in Tequila , Jalisco

1Colegio de Postgraduados-Campus Montecillo. Carretera México-Texcoco km 36.5. Montecillo, Estado de México, México. CP. 56230, (lusmilah@hotmail.com). 2Colegio de Postgraduados-Campus Puebla. Boulevard Forjadores de Puebla Núm. 205. Santiago Momoxpan, San Pedro Cholula, Puebla, Puebla. CP. 72760, (agroecologia-iof@ yahoo.com; mtornero@colpos.mx; jorgehp06@yahoo.com.mx). 3Universidad de Guadalajara-Centro Universitario de Ciencias Biológicas y Agropecuarias. Camino Ramón Padilla Sánchez Núm. 2 100. Nextipac, Zapopan, Jalisco. CP. 45510. (ramonrod@cucba.udg.mx). §Autor para correspondencia: evaltier@colpos.mx.


Abstract
The objective of this research was to compare two ways of agrosystem management for production of Agave tequilana Weber var.azul in the Municipality of Tequila, Jalisco at the basis on agroecological practices made by producers under the traditional agrosystem with polycropping (ATP) and under the conventional agrosystem with monocropping (ACM).A survey was applied to 25 ATP producers and 25 ACM producers in 2015.Eight cropping practices were considered: 1) intercropping (polycropping); 2) addition of organic matter to soils through pasturing; 3) agave plantation in contour levels; 4) soil and water conservation practices; 5) crop rotation; 6) land rest; 7) age staggering of agave plants; and 8) reduction of agrochemicals for weed control.The results show that producers made more agroecological practices in ATP than in ACM.Practices of intercropping and crop rotation have the highest significant differences between ATP and ACM.An index of agroecological practices in Agave tequilana (IPAAT) based on the number of agroecological practices.Most of ACM (60%) were classified at medium level (3 to 4 agroecological practices) de los ACM (60%) se clasificaron con un nivel medio de IPAAT (3 a 4 prácticas agroecológicas) y la mayoría de los ATP (72%) alcanzaron un nivel de IPAAT de alto o muy alto (5 a 7 practicas).La conclusión es que el ATP tiende a ser más sustentable que el ACM porque tiene un IPAAT mayor.

Introduction
The dominant farming system in the agave landscape of Tequila municipality is monoculture of Agave tequilana Weber var.azul, characterized by a high degree of intensification of cultivation practices, extensive areas covered by agave, alteration of diverse ecosystems, negative effects on biodiversity and uncertainty in the commercialization of blue agave (Valenzuela, 2003;Suárez, 2011;Hernández, 2014).
In the southern region of the state of Jalisco, Zizumbo et al. (2013) report that the expansion of agave monoculture generated soil erosion, pollution and displacement of traditional food crops, which threatens agricultural biodiversity in central-west and south areas of the state (Vargas et al., 2007).Santacruz et al. (2008) point out that monoculture damages produce serious phytopathological problems due to the Agave tequilana long biological cycle.
In the Municipality of Tequila, two management types of agave agricultural systems are practiced (Ceja et al., 2011): a) conventional agrosystem with monoculture (ACM) is characterized by land use dedicated only to Agave tequilana plantation, the whole harvest of agave is for selling, mainly flat land, mechanized cropping, mixed labor (family and hired), the latter mainly in charge of tequila industries, and b) traditional agrosystem with polyculture (ATP) in which producers carry out traditional agricultural practices that mainly interweave maize and beans.It has been documented that the agave is intercropping with peanuts, jamaica and fruit trees (Herrera, 2013).Agricultural practices differ after planting, as practicing polycropping farmers do more agricultural practices, but they also have more yield because of crop diversification.
Con base en lo anterior, se estudió el sistema de producción de Agave tequilana bajo un enfoque agroecológico que posibilita un análisis de la sustentabilidad de los agroecosistemas.Bajo estas premisas, se identificaron ocho prácticas agroecológicas: 1) intercalado de cultivos (policultivo); 2) incorporación de materia orgánica al suelo por pastoreo de ganado; 3) plantación de agave en curvas a nivel; 4) obras de conservación de suelo y agua; 5) rotación The main disadvantages shown by monocultures (ACM) are high vulnerability of ecologically artificial and genetically homogeneous systems facing climate change, low resilience to extreme climate events and susceptibility to pests, lack of biodiversity and biologically active soil, inefficient recycling of nutrients and dependence on external inputs and high agrochemicals use (Sevilla and Soler, 2010;Altieri and Toledo, 2011;Gliessman, 2013).
Negative environmental impacts identified on ACM, especially in industrial crops, are: pollution, depletion of water sources, incidence of soil desertification and deforestation.
On the other hand, González (2011) indicates that large areas of agave plantations have been intentionally deteriorated and abandoned aiming to induce a change of crop, mainly maize.Therefore, it is advisable to avoid monoculture and foster productive pluriactivity in agave, that is to say, diversification of activities such as cattle raising, tourism, introduction of species of native agaves and intercropped crops.
Diversifying activities can contribute to improve income and availability of food for agave producers and their families in the municipality of Tequila and to minimize the dependence from the cultivation of blue agave.They mainly intercalate agave with other crops such as maize, beans, zucchini, peanuts and fruit trees (Valenzuela, 2003;Gómez, 2012).In the same way, Armbrecht (2009) points out that polycropping is characterized by: productive diversification, use of ecological technologies, higher yields, reduction of pest and weed damage, and improved efficiency of water, energy, light and nutrients because different species of plants are located in different heights, canopies and needs, also showing a better edaphic efficiency (Yahuza, 2011).Therefore, polycultures show better agricultural and environmental conditions than monocultures.
Based on the above, the Agave tequilana production system was studied under an agroecological approach that allows an analysis of agroecosystem sustainability.Under these premises, eight agroecological practices were identified: 1) intercropping (polyculture); 2) incorporation of organic matter into the soil by livestock grazing; 3) agave plantation in level curves; 4) soil and water conservation works; 5) crop rotation; 6) land rest; 7) Age staggering of agave plants; and 8) decreased application of herbicides.de cultivos; 6) descanso de tierras; 7) escalonado de las edades de las plantas de agave (escalonado es el termino local para diversificar las edades de las plantas de agave); y 8) disminución de la aplicación de herbicidas.Se asume que la realización de un mayor número de prácticas de este tipo fortalece la sustentabilidad del agrosistema.

Los datos se analizaron con el programa Statistical Package for Social Science (SPSS). Se realizaron pruebas estadísticas paramétricas (prueba t Student para datos relacionados
It is assumed that the realization of a greater number of practices of this type strengthens the sustainability of the agro-system. The objective of this research was to compare the management methods of the agave agricultural system: the traditional agrosystem with polyculture (ATP) of hills and flat areas and the conventional agrosystem with monoculture (ACM) of slopes and land without slope to identify agroecological practices tending to sustainability, as well as to know the perception of the producers with respect to the ecological management in the agaveras plantations.

Study area
The study was conducted in the municipality of Tequila located in the state of Jalisco, Mexico.It has an altitude between 500 and 2 900 m and the main climates are: warm subhumid and semiwarm, the temperature oscillates between 14 and 26 °C, with a precipitation of 700-1 100 mm annually and Leptosol and Luvisol as dominant soils.The municipality is the third place in area at state level, with a total of 4 720 hectares of agave in the 2015 year.

Research techniques
A survey was applied to the agaveros in the municipality of Tequila who practice two agrosystems: a) traditional agrosystem with polyculture; and b) conventional agrosystem with monoculture.The characteristics of land plots were: a) plantations of Agave tequilana Weber var.azul; b) plants older than one year; c) plantations with polyculture; and d) plantations with monoculture.The population of agave producers in the municipality of Tequila was 101, from which a sample size was calculated with a reliability of 95% and an accuracy of 10%, resulting in 49.21≈ 50 producers.The sample was distributed in 25 farmers who practiced ATP and 25 ACM.
Data were analyzed with the statistical package for social science (SPSS).Parametric (Student-T-test for dependent data) and non-parametric (U Mann-Whitney for two independent samples, contingency tables and correlation coefficient) statistical tests were performed to measure and compare agroecological practices performed in de muestras dependientes) y no paramétricas (U Mann-Whitney para dos muestras independientes, tablas de contingencia y coeficiente de correlación) para medir y comparar las prácticas agroecológicas realizadas en dos tipos de manejo: agrosistema convencional con monocultivo (ACM) y agrosistema tradicional con policultivo (ATP).

Agroecological indicators and practices
Indicators of agroecological practices were used according to Reijintjes et al. (1992), who propose five ecological principles for the design and management of sustainable agroecosystems: 1) to ensure soil conditions mainly contribution of organic matter; 2) to optimize and balance availability and flow of nutrients, especially nitrogen fixation, and the complementary use of external fertilizers; 3) to minimize losses through practices with soil and water conservation; 4) to optimize pest and disease control; and 5) synergy of use of genetic resources, combining in integrated agricultural systems with a high degree of functional diversity.Moreno (2010) proposes something more specific which is an agronomic management index (IMA) consisting of five indicators: 1) number of practices that allow the diversification of species; 2) amount of organic matter in soils; 3) number of practices that provide optimal soil conditions; 4) type of management of pest and disease control; and 5) type of weed control.They assume that the greater the IMA value the ecosystem tends to be more sustainable, since agroecological practices that are used are environmentally friendly, are more economically accessible, and are socially inclusive because agricultural practices involve more to the producer with the agroecosystem.

Results and discussion
The number of land plots per farmer ranges from one to four, an average of 1.74.The average number of plots by ATP producer is 1.56 and 1.92 by ACM and land size is 6.3 ha in ACM and 4.68 ha in ATP, with a difference of 1.62 ha, a t test was applied (t= 1.359; p= 0.182) and no significant difference was found, although ACM producers have larger land.Regarding the number of land plots per producer destined to intercropping is 1.5, and the intercropping size land cultivated per hectare fluctuates between 0.25 until 0.5, in which agave is intercalated with maize, beans, peanuts and fruit trees.
The land size and number of plots show that farms are small units and have a low scale production of Agave tequilana Weber var.azul.A correlation was performed to determine the relation between the intercropping land size and system management type (r= 0.928; p= 0).The relation between intercropping land size with the type of management system indicates that it is significant, that is to say, land size in monoculture is significantly larger than in polyculture.

Agroecological practices in ATP and ACM
The agroecological practices analyzed in this research for ATP and ACM are: 1) intercropping (polyculture); 2) incorporation of organic matter into the soil by grazing livestock; 3) agave plantation in level curves; 4) soil and water conservation works; 5) crop rotation; 6) land rest; 7) Age staggering of agave plants; and 8) decreased herbicide application.

Intercropping (polyculture)
This practice is exclusive to ATP, 44% intercrop agave with maize and beans, 24% intercrop only with maize, 8% cultivate a mix of beans and peanuts, another 8% cultivate maize, beans and peanuts, while 4% only intercrop agave and peanuts, an equal percentage with fruit trees such as lime, avocado and plum, and finally, 8% intercalate maize, peanuts and fruit trees (Figure 1a and 1b).ASERCA (2000) states that most farmers believe that introducing crops such as maize in their plantations leads to competition for nutrients and, in a contrary opinion, some producers pointed out that fertilization and sanitary measures applied in maize, peanut or beans are useful and allows them to obtain additional income.agave con cacahuate; un porcentaje igual con frutales como limón, aguacate y ciruelo; y 8% intercala maíz, cacahuate y frutales (Figura 1a y 1b).ASERCA (2000) refiere que la mayoría de los productores opinan que introducir cultivos como el maíz en sus plantaciones origina competencia por nutrientes y en una opinión contraria algunos productores señalan que la fertilización y medidas sanitarias aplicadas en maíz, cacahuate o frijol, son útiles y les permite obtener un ingreso adicional.
Los meses destinados al pastoreo del ganado son después del temporal de lluvias y especialmente cuando se intercalaron otros cultivos en las plantaciones de agave.Se realiza el libre pastoreo a partir del tercer año del ciclo de vida del agave, ya que la planta tiene mayor vigor y por lo tanto es menos vulnerable al daño por el ganado.Introducen de 3 hasta 18 unidades de animal por ha, el promedio es de 7.64 cabezas.Pastorean entre uno hasta los siete años del total del ciclo biológico, en promedio 3.66 en el ATP y 4.2 años en el ACM.
Producers differ about the purpose of intercropping, however it is important to note that even ACM producers have a positive opinion and even prefer intercropping, but the pressure of the tequila industries force them to maintain monoculture.The main reason for intercropping maize is to obtain food for cattle and human consumption (28%), another percentage only cultivates products for human food (20%) and 16% food exclusive for livestock.In all cases, agave producers argue that only the first years of cultivation are intercropped (three to four), after that agricultural practices are difficult to do.According to Valenzuela (2000), suggests intercalated crops area relevant when they are short-cycle, legumes and are harvested on time.

Incorporation of organic matter into the soil by grazing livestock
The producers point out the pertinence of the pastoral use in their plots because this practice has three purposes: a) weed reduction through cattle feeding; b) biological fertilization of plantations; and c) reduction of pasture purchases.
In the ACM, 40% (10 agave producers) introduce livestock on their plots, out of which 32% do so in rotation from one plantation to another and 8% do it in a seasonal or deferred way before the dry season.On the other hand, 60% of ATP producers graze livestock (48% rotational and 12% continuous).
The months for cattle grazing are after the rainy season and especially when other crops were intercropped into the agave plantations.Free grazing is carried out from the third year of the agave life cycle, since the plant is more vigorous and therefore less vulnerable to damage by livestock.They introduce from 3 to 18 animal units per ha, the average is 7.64 heads.They feed from one to seven years of the total biological cycle, averaging 3.66 in ATP and 4.2 years in ACM.The months free of cattle during the productive cycle in plantations oscillates from 1 to 34 months, the average is 4.14 months.
In ACM, the mean is 6.4 months and is 2.6 months in ATP.
introduce three to 18 heads or animal units per ha, the average is 7.64 heads.They feed from one to seven years of the total biological cycle, averaging 3.66 in the ATP and 4.2 years in the ACM.The months they leave the cattle free during the productive cycle in the plantation oscillates between one and 34 months, the average is of 4.14 months.In the ACM the mean is 6.4 months whereas in the ATP it is 2.6 months.
Producer have conflicting opinions about this practice, on one hand, some say that livestock grazing is necessary to remove soil, fertilize the soil, weed control and avoid pests, it coincide with what Moreno et al. (2011); Hernández (2014) say.On the other hand, there are producers who do not graze their livestock because they consider it harmful to crops and soils.Half of them (50%) do not do this practice because it slows agave growth and decreases its quality, compacts the soil, damages the plants and when seedlings are newly planted they are pulled by cattle, in agreement with the indicated by García and López (2009).Some agave producers point out that the use of cattle is aggressive to plantations, because they bite mother plants or in some cases when they are small (from one to three years) cattle tear them from root and the same is done with the seedlings, causing damage and therefore losses.For these reasons they recommend the use of remuda (horses, mules and males), since they have observed to be less harmful to agave plants.

Agave plantation in level curves
Plantations in level curves is a practice carried out by the great distillers and has been spreading among small producers.
Although it is suggested planting rows in curves at a level to reduce soil losses at tolerable levels, this agroecological practice is used a little bit, only 24% of the producers apply this method in equal proportion between ACM and ATP; that is, 12% for each system.In ACM, it is performed when the slope is from light to flat and in the ATP when the slope is from moderate to flat.The level curves are related to the works for soil and water conservation; however, the agave producers perform in a higher percentage, conservation works and not level curves in their plots.
Los meses libres de ganado durante el ciclo productivo en la plantación oscila entre uno y 34 meses, la media es de 4.14 meses.En el ACM la media es de 6.4 meses mientras que en el ATP de 2.6 meses.

Plantación de agave en curvas a nivel
La plantación en curvas a nivel es una práctica realizada por las grandes destiladoras y se ha difundido entre los pequeños productores.A pesar de que se sugiere plantar hileras en curvas a nivel para reducir la pérdida de suelo en niveles tolerables, esta práctica agroecológica es poco usada, solo 24% de los productores aplican este método en igual proporción entre ACM y ATP; es decir, 12% para cada sistema.En el ACM se realiza cuando la pendiente es ligera y plana y en el ATP cuando la pendiente es de moderada a plana.Las curvas a nivel están relacionadas con las obras de conservación de suelo y agua, no obstante, los agaveros realizan en mayor porcentaje obras de conservación y no curvas a nivel en sus predios.
In lands where this practice is not used, it is due to traditional schemes of cultivation, used to planting in rows.
On the other hand, they indicated that when there is land in "ceboruco" (land of eroded hills) it is recommended.In this research in Tequila it was found that only 12 out of 40 agave producers make level curves in comparison to conservation works.Rodríguez et al. (2005) indicate that the improved native maize crop system intercalated with mezcalero agave under level curves and living walls system is feasible for areas that do not have water for irrigation in degraded hills.

Soil and water conservation works
Studies conducted by Guevara et al. (2012) in agave conclude that the lack of knowledge of crop management (cultural and agronomic) and of the optimum regions for agave, it has triggered soil degradation process.Some strategies proposed to reduce erosion are: 1) soil conservation practices on land with slopes of 5% or higher, such as: a) minimizing agricultural implements use to the minimum; b) not to use agrichemicals; and c) manual cleaning and weed control in crops; and 2) to avoid the partial or total elimination of natural vegetation.
The percentage of producers performing these conservation practices is high (80%).These include: work of soil and water conservation (34%) (Stone constructions, roadways, little dam, chains, sacks with stones or soil and wall with loose stones); gather the "trash" (litter and branches) and place it by the shore; construction of ditches, earthen bunds, fences and masonry.It should be noted that, conservation works (58.82%) are more frequently constructed in ATP compared to ACM.The t student test (t= 2.359, p= 0.022) indicated that there is a statistical difference between both ways of management.

Crop rotation
Crop rotations increase yields, add organic matter to soil and thus increase soil fertility.It is recommended a rotation of different species and nutritional needs, as is the case of beans and maize, these crops are the most rotated by agave producers (44%).More rotations are done in ATP (30%) than in ACM (14%).The reasons for rotations are: 34% of agaveros indicated that it is to rest their land, to avoid nutrient wasting, to soften and to "vitamin" soils and 8% of them do it to change seeds because it improves the production and nourishes the soil.Nitrogen addition is achieved by rotating legume crops, it suppress insects, pests and diseases by effectively breaking the life cycle of pests, and the absence of these eliminates the fundamental mechanisms of self-regulation (Altieri, 2009).

Soil rest
This type of practice improves soil conditions in plantations by improving fertility and microbiota (Sivila and Angulo, 2006).When a land is cultivated without rest, the soil has no time to recover part of its natural fertility necessary for the plants growth.78% of agave producers do this type of practice, they are distributed on 36% in ACM and 42% in ATP.Most of the producers indicated that this practice is fundamental in soils recovery.The rest period varies between one and two years with an average of 1.48.

Age staggering of agave plants
Age staggering is a strategy against the possibility of total loss or production reduction and maintenance of agave plantations.In the municipality of Tequila, agave producers have plantations of different ages to have continuous production every year, although the most common is that they have plantations with differences of two years.The vegetative cycle of agave plant lasts an average of 7 years, allowing this practice.For this reason, 48% of producers carry out age staggering in their plantations, from which 30% are producers of ATP and the rest of ACM.
Agave producers have an average of 5.2 years using age diversification in their plantations, although they had two cases of producers that have been doing age staggering of agave plants for 20 years.This activity is a practice of recent incorporation into agrosystems.Regarding the average number of years that agave producer have practiced age staggering is 4.2 years in ATP and reached 6.7 years in ACM.
The producers reduce the cost of production with this method through two ways: 1) selection of agave shoots, the producers separate the healthy agave shoots of their own plantations and grow it according to size, age and vigor; and 2) gradual investment, as the agave producers have the economic resources they acquire the young shoots, for this reason heterogeneous plantations are observed in a land plot.

Descanso de tierras
Este tipo de práctica permite mejorar las condiciones del suelo en las plantaciones por un mejoramiento de la fertilidad y microbiota (Sivila y Angulo, 2006).Cuando un terreno se cultiva sin descanso no se le da tiempo al suelo de recuperar parte de la fertilidad natural necesaria para el crecimiento y desarrollo de las plantas.El 78% de agaveros realiza este tipo de práctica, que se distribuyen 36% productores en ACM y 42% corresponden al ATP.La mayoría de los productores indicó que esta práctica es fundamental en la recuperación de los suelos.El lapso de descanso del suelo varía entre uno y dos años con una media de 1.48.

Decreased application of herbicides
Producers carry out the following practices that significantly reduce the use of herbicides: 1) agroecological: manual control of weeds, free grazing of livestock and production of organic inputs; and 2) agroindustrial: precise or minimum dosages of herbicides to reduce costs (based on supplier recommendations) and collective purchase.More than half of the producers opt for manual control to reduce the cost and dependence of herbicides, out of which 38% are from ATP and 30% from ACM.The proper use of herbicides doses was only recurrent in ACM.

Index of agroecological practices in Agave tequilana (IPAAT)
Descriptive analysis of agroecological practices was complemented by performing t Student tests for the whole set of agroecological practices.The U Mann Whitney test was performed to know similarities between different practices and it was found that in rotations and intercropping between both agroecosystems, they show significant statistical differences (Table 1).productores se concentraron entre los niveles medio y muy alto porque realizan de tres a siete prácticas agroecológicas por unidad de superficie (ha).

An index of agroecological practices in
La mayor parte de los productores del ATP (72%) se concentraron entre los niveles alto y muy alto.El número promedio de prácticas del ATP fue de 5.52 prácticas que se clasifica en el nivel de IPAAT muy alto.En tanto que la mayor parte de los productores del ACM se concentraron en el nivel medio.El promedio del número de prácticas agroecológicas del ACM fue de 3.32, que se clasifica con un nivel medio de IPAAT.La diferencia entre ambos sistemas es de 2.2 prácticas en promedio.En el Cuadro 2 es apreciable la ausencia de valor excelente en el ACM, de igual forma de productores en ATP con valor nulo.Esto significa que aun en los monocultivos de agave se realizan algunas prácticas que pueden considerarse agroecológicas.Se aplicó prueba de t Student (t= -0.5292; p= 0) mostrando que hay diferencia estadística.
between medium and very high levels because they carry out from three to seven agroecological practices per unit area (ha).
Most of the ATP producers (72%) were concentrated between high and very high levels.The average number of practices into ATP was 5.52 which is classified at the very high IPAAT level.While most of the ACM producers concentrated on the medium level.The average number of agroecological practice into ACM was only 3.32, which is classified with a medium IPAAT level.The difference between the two systems is 2.2 practices on average.Table 2 shows the absence of excellent level value among ACM producers, in the same way, there is no null level value into ATP producers.This means that even in agave monocultures some practices are done that can be considered agroecological.A t Student test (t= -0.5292; p= 0) was applied showing no statistical difference.

Conclusions
Eight agroecological practices were identified to compare two types of agroecosystem managements of Agave tequilana Weber var.azul: traditional agroecosystem with polyculture (ATP) and conventional agroecosystem with monoculture (ACM).An index of agroecological practices in Agave tequilana (IPAAT) was generated based on the number of practices done by agave producers.Based on the IPAAT, it is concluded that more agroecological practices are carried out into the ATP than into ACM, therefore it is inferred that ATP tends to be more sustainable than ACM.
El ATP está más ligado a sistemas de cultivo tradicionales para la subsistencia de los agaveros y el ACM al control del sistema de cultivo ejercido por las industrias tequileras.
Rotations and crop diversification were the practices that had the most significant differences between ATP and ACM.Soil and water conservation works and land rest were the most recurrent in both systems.The most important agroecological practice was intercropping of Agave tequilana Weber var.azul with annual crops such as maize, beans and peanuts, not only because of the number of farmers who did it but also because this practice implies a different plantation management under ATP with regard to ACM.
ATP is more linked to traditional farming systems for the subsistence of agave producers and ACM to the control of the cultivation system imposed by tequila industries.

Prácticas agroecológicas realizadas y número de productores por manejo de sistema. Table 1. Agroecological practices carried out and number of producers by management system.
Agave tequilana (IPAAT) was generated based on the number of ecological practices done by producers of ATP and the ACM, as shown in Table2.Agave producers were concentrated