Study area

The Totonacapan region is the most important production area in Mexico and is located north of Puebla (it includes 61 municipalities) and in north-central Veracruz (20 municipalities) (Figure 1).

Figure 1 Spatial location of the Totonacapan region composed of municipalities of Puebla and Veracruz.  

Due to its physiographic and edaphoclimatic characteristics, it is an optimal region for the development of vanilla cultivation, since subtropical, warm and humid climates are located in altitudes below 600 m, with temperatures ranging from 20 °C to 32 °C and average annual rainfall ranging from 1 500 to 3 000 mm, in addition to having land with excellent drainage, organic matter greater than 3.5%, with a pH of 5.5 to 7 and slopes of 10% to 40% (^{INIFAP, 2011}; ^{SAGARPA, 2012}).

The Totonacapan region collects the waters of the Panuco, Tuxpan, Cazones and Tecolutla rivers, which allows the development of livestock, forestry and agriculture, with crops of corn (Zea mays), beans (Phaseolus vulgaris), squash (Cucurbita spp.) and pepper (Capsicum annuum) as main for self-consumption. In addition to commercial species such as coffee (Coffea spp.), sugar cane (Saccharum officinarum), tobacco (Nicotiana tabacum), pepper (Pimenta dioica), banana (Musa paradisiaca), sesame (Sesamum indicum), ginger (Zingiber officinale), litchi (Litchi chinensis), citrus (Citrus sinensis) and vanilla (^{SIAP, 2018}).

Socioeconomic characterization of vanilla production in the Totonacapan region

To determine the socioeconomic factors that explain the changes in area planted and yield in the field in Totonacapan, a survey was conducted between November 2017 and February 2018 to 175 vanilla producers (20% of the total, statistically sufficient sample according to the theory of sampling) based on their availability and references in the region. In addition, specialists from the Autonomous University of Chapingo (2), the Postgraduate School (1) and representatives of the Product System Committee of Puebla (2) were interviewed. The interview guide considered phytosanitary, climatic, social and market aspects.

The survey included questions about age, schooling, cultivated area, land tenure and percentage that represents the activity in the family income. According to the CIMMYT survey design guide (1993), aspects regarding the knowledge that the producer has about irrigation, fertilization, pest and disease control, as well as other factors that could condition the expansion of the crop and increase its productivity, such as the climate, the physiography of the plot, production costs, management of subsidies and credits, management and parcel equipment, among others.

Vanilla productive potential using the maximum entropy algorithm (MaxEnt)

Through in situ tours in 2016 and with the help of the directors of the Association of Vanilla producers of the State of Puebla, a total of 167 points with presence of vanilla in the field of the municipalities with production were georeferenced for their accessibility; this information was combined with climatic and edaphic variables of the area, with a resolution of 30 s (1 km²), the first correspond to the 19 bioclimatic variables and annual evaporation, and the second are: calcium, electrical conductivity, organic carbon, potassium , magnesium, organic matter, sodium, pH and sodium adsorption ratio, available in the global database of climatic surfaces WorldClim.

The points with presence of vanilla in field (167), were introduced in the MaxEnt algorithm (^{MaxEnt, 2016}) in comma delimited format (.csv) and the climatic and edaphic variables in ASCII format (.asc), following the methodology de ^{Hijmans et al. (2005)} was determined the productive potential of the region for the cultivation of vanilla. The results were imported into DivaGis v7.5 (^{DivaGis, 2016}) and converted into grig format (.grd) to be viewed as images. The probability of occurrence of the species was categorized into areas with potential i) very low [0.0 - 0.2]; ii) low (0.2-0.4); iii) medium (0.4-0.6); iv) high (0.6-0.8); and v) very high (0.8-1), according to a Likert scale of homogeneous intervals.

Vanilla productive potential using multicriteria evaluation

From the geoportal of the National Commission for the Knowledge and Use of Biodiversity (CONABIO), the georeferenced data were extracted in vector format 1: 1 000 000 in altitude, precipitation, temperature, pH and soils and in raster format with a resolution of 5 min the digital elevation model that served to delimit the slopes of the region. The climatic and edaphic ranges were used where the highest field yield is obtained: altitude (less than 600 m), precipitation (1 500 to 3 000 mm), temperature (20 to 32 °C), type of soil (with organic matter) greater than 3.5% and pH higher than 5.5) and pending (10 to 40%) (^{INIFAP, 2011}; ^{SAGARPA, 2012}), to discriminate those areas that do not meet these specific needs.

For the procedure of weighting and comparison of said aptitude factors, the Weighted Overlay module of ArcMap^® (^{ArcMap, 2010}) was used, the evaluation scale (very low, low, medium, high and very high) was determined by routes in field and according to the opinion of specialists in the production of vanilla of the Autonomous University Chapingo (UACH), College of Postgraduates (CP) and representatives of the Committee System Product of Puebla AC.

Discrimination of the productive potential by land use and current vegetation

Finally, to delimit those regions suitable for the expansion of the crop, areas were determined by productive potential (very low, medium, high and very high) based on the use of soil and vegetation reported by the ^{INEGI (2016)} scale 1: 250 000 of the VI series. Through field trips with directors of the Association of Vanilla Producers of the State of Puebla AC, the information obtained by the two methods (MaxEnt and MCE) was verified, which served as the basis for the proposal to establish new areas for the cultivation of Vanilla planifolia with greater productive potential.

Socioeconomic characterization of vanilla producers in the Totonacapan region

The Product System Committee of Puebla AC indicates that in the region of Totonacapan there are a total of 871 producers who cultivate 2 653 ha of vanilla, of which 80% are men and 20% women, belong mostly to the Otomi ethnic groups and totonaco. Of the total of producers, 487 have this crop in land of small property with a planted surface of 1 486 ha, and 384 producers develop the activity in lands of common property with a total of 1 167 ha.

95% of the producers surveyed produce vanilla as a secondary activity, and have as main sources of income, the production of corn, beans, coffee, pepper and livestock. In most cases the production of vanilla is practiced more by a cultural factor than by the profitability of the crop, since this activity is inherited from generation to generation and the pods are used for the manufacture of crafts that are occupied in the festivities regional

Experts from the UACH, CP and representatives of the Product System Committee of Puebla AC, consider the smallholding (<0.5 ha in 79% of producers), the low level of study (<8 years), the age (from 55 to 62) years) and the fact that the production of vanilla means a secondary activity that complements the family income (Table 1), impedes the development of the vanilla sector in the region, by limiting the area sown and in many cases converting it to more profitable crops.

^{Alcon et al. (2008)} point out that older producers are more reluctant to change their production systems, considering that they have always done so and for them it is well done. On the other hand, ^{Soto et al. (2006)} establish that it is more complicated for producers with small plots to strengthen their production systems with new infrastructure, since in many cases they represent a secondary activity in their family income. In this regard, ^{Álvarez and Crecente (2000)} describe the benefits of land consolidation (through rights-of-use session) as a measure of adaptation to smallholdings and crop spraying.

Factors of crop management and access to credit

Added to the problems of smallholding, the vanilla producer of the Totonacapan region faces a scarce development of technological packages for the management of the crop, which reduce production by not considering programs for the control of pests, diseases, fertilization and irrigation. 98% of the planted area is managed under a rainfed water regime, only 2% uses irrigation. 90% of the producers surveyed mentioned that they have noticed variations in rainfall patterns, so they are aware that in the future watering may be required to maintain the activity. However, they do not consider the climatic factors, nor the physiography of the plots as limiting aspects for production.

95% of the producers surveyed consider that the expansion of the crop is limited by phytosanitary aspects related to the control of pests and diseases such as red bug (T. confusus), hairy worm (P. aunifera), root and stem rot (F. oxysporum) and anthracnose (C. gloeosporioides). In addition to the zero support for access to credit and subsidies that facilitate the parcel equipment and incorporate technological packages (especially fertilization) that improve productivity in the region. Practically 100% of producer’s self-finance production costs, which in an unstable market in prices causes many of them to abandon the activity by converting their plots to more profitable crops.

^{INIFAP (2011)}; ^{SAGARPA (2012)}, consider that the adequate management of the problems of fertilization, pests and diseases associated with the production of vanilla in the region, substantially improve the productivity of the sector. By virtue of this, as of 2011 they implemented technological packages that included these aspects, with good results in their beginning when increasing the yields in the field. However, due to lack of investment, continuity has been scarce. To solve this problem, the Product System Committee of Puebla AC, currently manages trusts instituted in relation to agriculture (FIRA) credits to the producer to strengthen the production infrastructure.

The market factor: lack of added value

The average yields in field of the region are of 0.449 t ha^-1 with production costs of $60 000.00 year ha^-1 and with gains superior to the $88 000.00 year ha^-1, these gains correspond to the sale of the pod in green whose market value ranges from $180 to $200 kg. In the region 94% of the producers do not give the beneficiary service where the selling costs are over $3 000 kg. This aspect has been addressed by ^{Jaramillo et al. (2012)}, ^{Jaramillo et al. (2013)} and ^{Xochipa-Morante et al. (2016)} who consider that this factor is what limits the expansion of the crop, since the producer considers the activity to be unprofitable and prefers to channel its inputs to economically more attractive crops.

^{Barrera et al. (2014)} mention that the international vanilla market imposes new and strict quality and safety standards on producers that they must abide by in order to be competitive; so the international market is a factor that directly affects the productivity of vanilla. By virtue of this, the Product System Committee of Puebla AC, implemented a series of workshops to promote among the producers of the region the vanilla beneficiation service, with which it is expected that they will substantially improve their income and the competitiveness of the vanilla sector.

Vanilla productive potential using the maximum entropy algorithm (MaxEnt)

The results obtained by the MaxEnt algorithm are highly significant with a reliability level of 95% (p-value <0.0001) and a coefficient of determination (R²) of 99.6%. Of the 29 edaphoclimatic variables used in the MaxEnt probabilistic model, four contributed with 88.1% of the prediction of zones with the highest productive potential for the vanilla crop. The most important were: increase in rainfall in the driest month (April: <60 mm year^-1) that contributed 56.3% of the prediction, followed by a low content of sodium in the soil with 13.1%, temperatures no higher than 30 °C in the hottest quarter (June-July-August) with 10.7% and high organic carbon content in the soil with 8%.

Therefore, according to the model, the factor that most affects the optimal development of the vanilla crop is the increase in precipitation in the driest month. This aspect was documented by ^{Barrera-Rodríguez et al. (2009)}; ^{INIFAP (2011)}; ^{SAGARPA (2012)}; ^{Flores et al. (2017)}; ^{Santillán-Fernández et al. (2018)} who agree that the adoption of irrigation during periods of low water substantially improves yields in the field, even without fertilization. On the other hand, the surveyed producers mentioned that they have perceived variations in rain patterns, so they do not rule out irrigation in the future.

Figure 2 shows the productive potential of the region classified in: i) very low; ii) low; iii) medium; iv) high; and v) very high.

Figure 2 Spatial representation of the estimation of the productive potential for vanilla in the Totonacapan region obtained by means of the maximum entropy algorithm.  

The current production areas and the areas planted during the year 2017 are also located, which were proposed for this crop before the Association of Vanilla Producers of the State of Puebla AC, and which were selected based on the results obtained and availability in the field. , when the producers voluntarily adopt the vanilla crop.

For the MCE an evaluation scale of five classes was built, with areas of potential i) very low; ii) low; iii) medium; iv) high; and v) very high (Table 2). The MCE turned out to be a more robust methodology, which considers larger areas compared to MaxEnt.

Figure 3 shows those areas in the Totonacapan region that meet the agroclimatic conditions of the crop, specific areas with medium, high and very high aptitude for the establishment of the vanilla, where to improve the management of the crop with aspects such as control phytosanitary, irrigation and fertilization, it is expected to obtain the best yields in the field of the region.

Figure 3 Spatial representation of the estimation of the productive potential for vanilla in the Totonacapan region obtained through multicriteria evaluation.  

The results were taken as a reference by the Association of Vanilla Producers of the State of Puebla AC, to manage the sowing of 100 ha with vanilla between May and June 2017.

When considering edaphoclimatic factors (annual precipitation, annual temperature, pH, type of soil and organic matter) and physiographic factors (altitude and slope) in the MCE, a greater area with medium to very high productive potential was delimited with respect to the results obtained with the MaxEnt algorithm, which did not include physiographic variables. However, both methods agree that the greatest productive potential is located northwest of the Totonacapan region, in the border areas of Puebla and Veracruz, which is where the current producing areas are located, with medium to very high productive potential.

Discrimination of the productive potential by land use and current vegetation

By using land use and vegetation cartography (^{INEGI, 2016}), it was possible to identify the current land use of the areas with productive potential for the cultivation of vanilla obtained by the MaxEnt and MCE algorithms (Table 3).

Coverages where the expansion of the crop can be potentiated are located in those areas where the continuity of an ecosystem is not put at risk; therefore, agriculture and grassland areas are the most optimal, as long as socioeconomic factors manage to reconvert them.

The results obtained by MaxEnt and MCE indicate that the areas with the greatest productive potential are located within the grassland areas that are destined for livestock, this information was validated through on-site tours with directors of the Association of Vanilla Producers of the State of Puebla AC and served as the basis so that between May and June 2017, vanilla is planted 100 ha to the northwest of the Totonacapan region, considering that in these areas with greater productive potential (high to very high) the probability of adaptation is increased, development and growth of vanilla.

Both methodologies agree that the areas with the greatest productive potential are located on agricultural, pasture and forest areas. It is proposed the cultivation of vanilla in those areas whose current use is destined to livestock (pasture) and to the agriculture of corn, beans, squash and pepper mainly. ^{Barrera-Rodríguez et al. (2011)}; ^{Jaramillo et al. (2012} and ²⁰¹³) establish that to increase the areas planted with vanilla in the Totonacapan region, the profitability of the crop must be improved in the face of other activities, giving an added value to the product that is marketed in green through the beneficiation process.