Plant material

The seeds of Ricinus communis L. were collected in the city of San Luis Potosí, where they were part of the flora on a backyard. The seeds of Moringa oleifera Lam., were acquired with a producer from the State of Morelos. Prior to sowing, the seeds were selected for their healthy appearance and weight. The seeds of Ricinus with less than 200 mg and Moringa seed weights below 150 mg were discarded. The measures and average weights of Ricinus seeds sown were 14.7 ± 0.3 mm long, 6.7 ± 0.2 mm wide and 478.8 ± 29.0 mg weight. Moringa were 12.9 ± 11.4 mm and ± 0.8 mm in width and 268.9 ± 42.9 mg of weight.

Experimental site and environmental conditions

The experimental plantation was established on the experimental field, Veracruz Campus, Graduate College of Agricultural Sciences, located in Manlio Fabio Altamirano, State of Veracruz (19° 16' 00" north latitude, 96° 16' 32" west longitude, 16 m elevation). During the experimental period, the campus weather station recorded weather data. The average maximum temperature was 30.5 °C (± 3.3) and minimum of 21 °C (± 2.7); humidity was 78% (± 5.9) and cumulative annual precipitation was 1 298 mm. During the first year the dry period began on October 30 and remained until 31 May, when the first rain was recorded. Therefore, the plants received no water for 213 days (dry period).

The terrain is characterized by shallow, stony soils. A physical-chemical analysis indicated that this soil has a clay texture, pH 6.6, bulk density 1.2 g cm^-3, electrical conductivity of 259.9 mS, and total N concentrations of 0.2%, 19.1 soluble potassium mg L^-1 and phosphorus 24.7 mg L^-1.

Planting, care and recording variables

The seeds of both species were planted on September 26, 2012, at the beginning of the rainy season to avoid irrigation activities. The land was previously weeding and plowed by tractor. The planting consisted of planting three seeds per hole at a distance of 2 m on the same row and 6 m between rows, for a total of three rows of three Moringa and Ricinus and with a length of 20 m each. The first outbreaks were recorded five days after sowing. Within seven days of the emergence proceeded to remove excess plants in each planting site, leaving only the larger ones.

The land was weeded every time the weed exceeded 20 cm. Variables recorded each month were: plant height, stem diameter, number of branches, number of leaves and seed production; and the initiation of flowering and fruiting of each plant was also recorded. Seeds obtained were measured and weighed, taking a random sample to determine the percentage of oil. Additionally recording and collecting insects considered harmful, sending specimens for recognition to the Postgraduate College in Agricultural Sciences.

Data analysis

Data on height and diameter of each species allowed to determine rates and growth curves, which were compared between both crops. The heights were compared using t tests monthly, with a significance level of 5%. Costs required to establish and maintain crops per unit area (ha) were estimated. The cost analysis was performed by comparing the association of Moringa and Ricinus against two typical crops of the region and the State of Veracruz: sugarcane and papaya.

Data for sugarcane were taken from the Instituted Trusts in Relation to Agriculture (FIRA, 2007) and data for papaya were taken from a technology package developed by the Sinaloa Produce Foundation (^{Muñozcano and Martínez, 2010}). Both figures were restated based on increases in minimum wages to the date. As for perennial crops like Moringa and Ricinus during the first year, higher expenses related to site preparation and plantation establishment, which considerably reduce these gains this paper estimated the potential revenue and are made cost-effective considering the first two years after planting. The estimate of the second year productivity was performed using the average of the last two monthly harvests for both missing months. This was done this way because the harvests in recent months tended to stabilize at very similar values.

Growth

The first emergence was recorded from the fourth day of planting and for the eighth day already had 80% of sites covered with seeds of Ricinus and 60% with the seeds of Moringa. The Figure 1 shows the average growth curves of both species during the first 16 months of its establishment. Both species had statistically similar growth up to 250 days after emergence (March 2013). From that moment, Moringa had higher growth than Ricinus, reaching the 12-month average heights of 4.3 m, with growth rates of 23 mm per day, while Ricinus had average heights of 1.8 m and growth rates of 3.3 mm per day. While stem diameter of Moringa had average growth rates of 0.28 mm per day, and these are 10 times higher than those of Ricinus.

Figure 1 Growth of Ricinus and Moringa. Beginning flowering and fruiting in over 50% of the plants, indicated with vertical dashes. Vertical bars represent the mean standard error. 

Flowering and fruiting

Ricinus Flowering was recorded in 10% of the plants at 77 days of emergence and 150 days more than 63% of the plants already had fruit. Flowering began with an average height of 48 cm. Meanwhile bloom in Moringa appeared in more than 50% of the plants after 11 months and only 19% of the plants had produced pods at the end of first year, achieving 50% fruiting plants to 16 months. The total weight of Ricinus seeds collected from the first year was 157 g per plant, with oil concentrations of 55%. No difference was found in the seeds of the mother plant, which also recorded 55% oil. 51.5 g of Moringa seed harvested per plant, with a percentage of 36% oil, slightly higher than mothers seeds, which was 34%.

Registered pests and their effect on survival

Upon completion of the first year, survival rates of Moringa and Ricinus were at 75 and 93.3%, respectively. Three species of phytophagous insects on crops Ricinus, were identified: Sagotylus confluens Say, Corythucha gossypii and Nezara viridula L., (in order of importance) which were observed from November. Because of its size and abundance, S. confluens, killed 25% of the plants before being controlled by two biweekly sprays of Carex (active ingredient, Cypermethrin 21.46%), diluted at 2% with tap water, applied during the month of January 2013. Eight months later, the bugs appeared again, so sprayings were applied again.

For avoiding pesticides, spraying was conducted with detergent Vel Rosita ^® at 5% (this detergent containing anionic and nonionic surfactants, optical brighteners, preservatives, opacifiers, colorants and perfumes, but it has no phosphate). However, after two weekly sprays, only managed to eliminate Sagotylus confluens and Nezara viridula, remaining Corythucha gossypii, which was not fatal to the plant, although it contributed to leaf loss and decreased production. Moringa alone was severely affected by ants (Atta mexicana Smith) which defoliated totally and repeatedly three seedlings until they were controlled entirely by repeated application of Foley 2% (methyl parathion 2%), which was sprinkled on the base of the stems of the seedlings and in the ant entries.

Investment costs and benefit-cost ratio

The Table 1 summarizes the costs of establishment and care of the crops Ricinus and Moringa in the Campus Veracruz. The costs of tracking of the soil were considered based on the cost of renting the equipment and the operator. Harvesting costs were higher because the seeds of Ricinus harvested every two weeks to prevent losing, as Ricinus plants were uneven. By keeping the crops without fertilizer or irrigation, the costs associated with these activities were not existent.

The Table 2 allows us to relate production costs of the Moringa and Ricinus association, compared to two traditional crops of Veracruz (papaya and sugar cane) during the first and second year. It is observed that the production of Moringa and Ricinus managed an investment lower than 15% compared with papaya and sugar cane.

Agro-climatic conditions of the region

Temperatures (20 °C - 30 °C) and precipitation (602 mm) recorded in the region are considered suitable for both crops (^{García-Roa, 2003}; ^{Reyes, 2006}; ^{Rico et al., 2011}; ^{Nielsen et al., 2011}). Warm weather is especially suitable for Moringa, which compromised productivity below 14 °C (^{García-Roa, 2003}).

In relation to the soil, the pH recorded was within the preferred range for both crops, not texture (clay) as heavy soils tend to accumulate more moisture and roots of crops do not tolerate both excess moisture for prolonged periods (^{Reyes 2006}, ^{Nielsen et al., 2011}). However, the experimental site was approximately 5% slope and good drainage, waterlogging smoothly. In addition, rainfall is presented only intermittently for five months, so that precipitation did not cause stagnant water and no problems were observed roots or plant loss by decay in either species during the season showers; so we can deduce that the soils in the study site, although heavy, did not present significant problems for the survival of the plantation.

Regarding macronutrients, the nitrogen, phosphorus and potassium are considered sufficient, since in the case of Ricinus much nitrogen is not recommended (no more than 25 kg per hectare, Soares et al. (2006) because it only promotes vegetative growth without increasing production; and has also been found that responds very little phosphorus (^{Nielsen et al., 2011}). Studies in Mexico have found that for soils low in nitrogen input type 60-40 -00 commercial fertilizer can increase yields by up to 50%, while the application of cattle manure at a rate two tons per hectare may increase production 30% (Rich et al., 2011). In Moringa, the application of 380 kg of phosphorus and 280 kg nitrogen per hectare in intensive crops (^{Price, 2000}) is recommended; plantations while for 1 600 plants per ha in Sinaloa applying 300 mg of KNO₃ per plant or 1 to 2 kg of manure or worm castings per plant was recommended (^{Pérez et al ., 2010a}). Since there are cattle in the region, using their manure as compost could be a much cheaper alternative and sustainable -evaluated to improve productivity in the case of Moringa fertilization.

Pest risk

The average humidity (78%) in the study site was much higher than recommended for growing Ricinus as percentages below 60% are suggested to avoid pests and fungi that attack this plant (^{Foild et al., 2001}; ^{Rico et al., 2011}). This situation could be seen to be an increased presence of herbivores at the beginning of the rainy season insects. These insects showed a marked preference for Ricinus on other adjacent plants and planted on campus, such as Jatropha curcas, Jatropha podagrica and Moringa, severely affecting the crop. Fumigation with substances of low toxicity, such as the Vel Rosita were not effective for the control of insects in Ricinus. The sensitivity of Ricinus to Corythucha gossypii has been documented as a severe problem (^{Varón et al., 2010}; ^{Rico et al., 2011}), and this insect could only be controlled by systemic, such as dimethoate and imidacloprid products that are toxic (^{Varón et al., 2010}).

Meanwhile, the Atta ants were also found to be highly detrimental to Moringa. These insects have been reported as important pests for this species in other regions (^{Pérez et al., 2010a}). Other threats were not evident in this study, which did not require major investments in Moringa for pest control. The pest control costs constituted 10% of the investment costs.

Performance and productivity

Ricinus plants showed good adaptation to the climate of the region and the dimensions and weight of seeds were similar to the average reported in elite seed collections of the National Research Institute of Forestry, Agriculture and Livestock (INIFAP) in the country, manifesting average size of 1.5 cm long and 1 cm wide, with average weights of 496 mg (^{Barrios et al., 2013}). The oil content recorded in the seeds (55%) is considered high among commercial varieties known for this species, which reported average content of 45% (^{Nielsen et al., 2011}), and superior elite materials of INIFAP that ranged from 47-50% (^{Rico et al., 2011}) while an analysis of seed harvested in the State of Veracruz found average oil content of only 23%, with maximum values of 33% (^{Martínez et al., 2009}), which makes them a very desirable germplasm for the region.

Furthermore, the rapid onset of seed production of this germplasm Ricinus, places it in a category of early compared to other germplasm found, reporting early onset of harvest for materials after 100 days (^{Zamora et al., 2011}) and between 120 and 130 days to Mexican elite materials (^{Rico et al., 2011}; ^{Barrios et al., 2013}). Production of the first and second year of 129.5 kg and 327.8 kg per ha, respectively, was lower compared to plantations elsewhere in the country that average figures were obtained from 700 kg per ha for the state of Michoacán (^{Rico et al., 2011}) and 2 500 kg per ha for Chiapas (^{Rico et al., 2011}).

Even if we consider the low density of plants per ha^-1 (825) of this plantation and the fact that neither irrigation nor fertilization, these production levels can be considered within the expected range for these conditions, it was not applied according to (^{Nielsen et al. (2011)} can fluctuate between 300 and 400 kg per ha. For all these features, the material used in this research is considered advisable on local materials for establishing productive purposes, as the state collects no information on provided better data (^{Martínez et al., 2009}).

The plants of Moringa, although they were in high average growth rates, considered typical of their species under good conditions (^{Alfaro and Martínez, 2008}), showed a flowering and late fruiting compared to commercial plantations elsewhere in the country who report onset of flowering at seven months and fruiting at 11 months (^{Pérez et al., 2010a}). A good point is that the percentage of oil on the first seeds was slightly superior than the mother seeds’ (2%), and for growing Moringa, a very low seed production in the first year is not necessarily a bad productivity, since this plant is also harnessed by harvesting its leaves, which can be consumed both by humans and livestock, to enrich the protein content of the diet or sold dried for tea with antibacterial and antioxidant properties (^{Alfaro and Martínez, 2008}; ^{Olson and Fahey, 2011}). Both options could represent an additional income that is not yet explored in the region.

Potential markets and selling prices

Before starting any cultivation is necessary to investigate the feasibility of selling in the market and the prices it can achieve. In the case of Ricinus income earned after two years is still not attractive, mainly because of its low price (Table 3). However, it has been found that with government support, as in the case of the State of Puebla, its latest price has come to be 10 pesos per kg (^{Olguin, 2014}), which in this case would generate a cost-benefit of per hectare to 17% the second year.

However, in the State of Veracruz there is still no support program for this crop by the Veracruz Institute of Bioenergetics (INVERBIO), so it would be advisable to manage the official support to these authorities, thus achieving higher benefits with this crop. Regarding Moringa, profits were higher because the seeds price can range from 50 to 1 000 pesos per kg (^{Pérez et al., 2010a}; ^{Mercado Libre, 2014}). The leaves, which can also be marketed both locally and nationally or used as a feed supplement for cattle, were not evaluated in this study, so further research is needed to explore this matter. However, sales via the Internet could be an alternative for customers and achieve good sales prices of seeds, although this requires more knowledge and training on the use of these technologies by farmers, who normally lack the financial resources and educational preparation for it. In these circumstances, it is recommended to manage the support of an educational or research institution that provides training, web design and marketing skills to promote their products.

When compared to other traditional crops on the State (papaya and sugar cane) during the first year, it appears that the production of these crops was quite low, so the potential income is reduced and the benefit-cost ratio is low as well, mainly due to lower selling prices and productivity Ricinus, which contrast with the case of Moringa, where high sale prices allow to obtain very attractive returns, which could even tip the handle as producer for monoculture. However, it is important to consider the potential benefits of the combination of these crops as a strategy of diversification of the productive system in areas where the population is in highly marginalized conditions and has no means to make large monetary investments.