Socio-economic and technological aspects

The characteristics of the surveyed sample, such as gender, age, education, access to services and roads, showed that the male gender predominated. There were no young farmers, they did not have basic services, and they had difficulties get products , with more costly production, as can be seen in table 2.

The sample consisted mainly of men (82%), while women represented only 18% (Tab. 2), similar to ^{Correa et al. (2019)} for squash and for yard-long beans (^{Martínez-Reina et al. 2019a}). In this productive system, there is a lower degree of participation by young people, with an average age of 48 years (minimum value of 23 and a maximum of 77 years) (^{Correa et al., 2019}; ^{Martínez-Reina et al., 2019a}, ^2019b). 50% of respondents had a primary education, 27% had a high school degree, and 17% had no education. 67% of the producers had a low educational level (^{Correa et al., 2019}; ^{Martínez-Reina et al., 2019a}, ^2019b). For public services, 56% of the surveyed producers had basic water and electricity services, and 44% said they have no service. 88% of the farmers said the access roads are in poor condition (^{Correa et al., 2019}).

Local technology aspects

The cultivation of the pink Zaragoza bean takes place mainly in Catatumbo and in the province of Ocaña (Department of Norte de Santander), extending to the municipalities of Rio de Oro (Department of Cesar) and throughout Serrania del Perija, up to the municipality of Barrancas in the Department of La Guajira (^{Méndez et al., 1997}).

The cropping activities carried out sequentially by the producer are presented below, classified as pre-establishment tasks such as soil preparation, crop management, and harvest and post-harvest tasks.

Plot selection. Producers consider different risk elements, such as susceptibility to flooding, proximity to a water source, and proliferation of root diseases from non-crop rotation. Soils for the Zaragoza bean should be sandy and clayey, well-drained, with a preference for light soils that allow good rooting; on the other hand, this crop also grows in strongly alkaline, heavy textured soils (^{Carvalho and Sgarbieri, 1998}).

Pre-cultivation activities. Before starting any activity, a farmer plans how the crop should be produced, defining the sowing date as conditioned by rain and the availability of water. Vegetable debris, such as trunks and branches, are collected, and the earth is removed in such a way that it is ready to be sown.

Soil preparation. Fifty-seven percent of the farmers carry out soil adaptation tasks manually, spending a total of five wages; 28% do it with equipment that consists of a plow and a rake, and 14% do it manually and mechanically, spending about four labor days in total.

Sowing. The sowing is done directly, spending an average of five wages per hectare. The amount of seed used on average is 35 kg ha^-1, of which 53% of the sample uses recycled seed from the previous harvest, i.e., in each harvest, the farmers select and allocate the seeds according to their criteria for the next sowing session, trying to choose those with no apparent damage. About 47% of the respondents stated that they buy certified seeds in agricultural warehouses.

To define the sowing season and carry out this activity, farmers consider factors associated with the environmental offer, better commercialization possibilities, and technical and technological capacities installed by the farmer. The former delimits the dates that the Zaragoza bean producers prefer for the establishment of their crops. Most farmers choose to plant their crops taking advantage of the rainfall that occurs during the year, i.e., considering two rainy seasons. In this sense, most farmers (60%) prefer to plant in November and December, and April and October.

Irrigation. The irrigation scheme implemented by farmers range from pressurized, those that use large flows or floods, and manual systems. On average, a total of 9 d ha^-1 during the crop cycle is used, i.e., 120 d on average.

The water sources are diverse and generally correspond to permanent sources, except those that use water from rainfall.

Beans are highly susceptible crops to water deficits and excess humidity; therefore, a water supply plan is required during the field crop cycle until the pod filling stage. For the 87-90-d-cycle of the bush beans in the Caribbean area, supplementary irrigation of up to 55 d is required. About two to three efficient irrigations per week are sufficient for good seed development and production (^{Lardizabal, 2013}).

Fertilization. More than 78% of the farmers fertilize chemically, regularly using fertilizers based on chemical compounds that have as active ingredients: nitrogen, phosphorus and potassium fertilizers during the first two fertilizations. As the crop production cycle progresses, the nutritional demand is higher; therefore, the farmers increase the doses of the fertilizers. Only 3% of the farmers fertilized with minor elements, while the application mechanism was use of foliar absorption products. Meanwhile, only 6% of farmers used organic fertilizer amendments (Lombriabono or earthworm fertilizer) as a supplementary source of crop nutrition.

Other regional studies have reported that 76% of the producers use chemical fertilizers for the Zaragoza bean, and 24% use a higher diversity of chemical and organic fertilizers, including urea, boron, triple 15, fertilizers with macro and micronutrients and vermicompost (^{Tofiño-Rivera et al., 2018}). It should be noted that the improved varieties of bush beans respond to soil fertilization, doubling their yield. Furthermore, fertilization improves their reaction against disease attacks (^{Pedroza et al., 2013}). In this sense, the pink Zaragoza bean can produce from 370.89 kg with low phosphorus to 867.25 kg with higher contributions of phosphoric fertilization (350 kg ha^-1 of triple superphosphate (TSP), equivalent to 45 kg of P₂O₅). In the seed, the phosphorus content is 55.40 ppm, and the zinc content is 21.85 ppm (^{Astudillo and Blair, 2008}).

Weed management. Chemical management is carried out as well as a combination of manual and mixed methods, including manual cleaning and herbicide application. Weed management that is carried out manually spends an average of 5 d ha^-1, and, in pre-emergence, chemical burning is applied using herbicides with the active ingredient glyphosate

Some regional studies have reported that the main weeds associated with the cultivation of the pink Zaragoza bean in the Caribbean are verdolaga (Portulaca oleracea L.), coco-grass or pasto coquito [Spanish] (Cyperus rotundus L.), gamba grass or pasto sabanero [Spahish] (Andropogon gayanus Kunth), common sowthistle or cerraja [Spanish] (Sonchus oleraceus L.), hairy crabgrass or pluma de garza [Spanish] (Digitaria sanguinalis Royle), angular winter cherry pega pega or toporopo [Spanish] (Physalis angulate L.), white clover (Trifolium repens L.), and Santa Maria feverfew or marihuano macho [Spanish] (Parthenium hysterophorus L.) (^{Tofiño-Rivera et al., 2018}).

Pest management. About 80% of the surveyed sample carried out chemical control, while a very low percentage applied plant-based insecticides. Moreover, it was estimated that less than 10% of the farmers did not carry out any kind of application. There were differences between the opinions of the producers regarding the identification of the pests that cause the most damage to the crops, both in the dry and in the rainy seasons, evidencing the lack of knowledge of farmers for the identification of insects and their associated damage, which include those commonly called whiteflies (the assumption is that it corresponds to the species is Bemisia tabaci, common in the region), the bean weevil (possibly a member of Curculionidae), the armyworm (Spodoptera sp.), and mites. Some regional studies have reported that mites, weevils and whiteflies are the most important pests (^{Tofiño-Rivera et al., 2018}).

Disease management. The diseases that attack this crop include phytophthora, alternaria, common bacterial blight, and wilting of the leaves (anthracnose). They are controlled with chemical methods by 80% of the farmers, using active ingredient fungicides and mancozeb.

Harvesting or pod recollection was carried out manually; on average, it has been calculated that about 15 wages are used for this activity, including internal transport.

Postharvest. The producers carried out threshing and shelling type II transformation. They packed the beans in 50-kg sacks of fique and, on average, obtained 1.7 t ha^-1. They sold their product in the local market and, at a low percentage (30%), in the plot.

Production costs and return indicators

The cost of cultivating one hectare of Zaragoza bean in Rio de Oro was COP 3,980,659, equivalent to US$ 1,180. Of this total cost, 79% corresponded to direct costs, while 21% were indirect costs. In turn, labor was 55% of the total costs, inputs accounted for 14%, and tools took 10% of the total costs.

The calculations provided the return on investment indicators (Tab. 3). The unit cost of a 1 kg of Zaragoza beans is US$ 8,694. First, the price of the inputs was taken as purchased by the producer individually. In the case of income, the yield of 1.7 t was taken and multiplied by the price to obtain a gross income of US$ 1,694.

The profitability was calculated with three approaches: The total approach was calculated at 43%, and the traditional concept was used. The technical profitability relates gross income to direct costs; here, estimated at 81%, meaning that physically, one invested monetary unit would yield an additional 81 cents. The possibility of recovering the investment is demonstrated through the 73.9% net profitability indicator, which showed that, with physical yields of 1.7 t, it is possible to generate profits. The technical efficiency was 848,070, which means that it perfectly compensates for the total costs of US$ 1,473.

For the economic efficiency, the sale price exceeded the unit cost of production, and, for this reason, each monetary unit invested in costs was recovered, generating an additional 43 cents.

The calculation of the marketing margins elucidated the price movements when it passed from one actor in the chain to another. In this case, when it leaves the farm of the producer, it passes to the intermediary and the final consumer through the gross marketing margin (GMM), which showed that, for every US$ 1 that the consumer pays, US$ 0.16 is captured through intermediation. This movement is moderate in that, by just marketing the product, a portion of less than 20% of what the consumer pays is taken.

In the case of the intermediary, this margin was higher, with a value of 30%, indicating that for every US$ 1 that the consumer pays, US$ 0.30 is captured by the intermediary. This means that the second link in the chain obtains a higher benefit by marketing the product, i.e., 30% of the difference between the price of the producer and the final price of the consumer.

The direct participation of the producer was estimated at 6.02%, which means that for each monetary unit paid by the consumer, the producer receives 6 cents, and the rest (94%) goes to intermediation.

Similar studies, such as the one by ^{Martínez-Reina et al. (2019a)} on long beans, have shown a gross marketing margin of 50%, much higher than what was found in the current study on the Zaragoza bean. In this case, the intermediary received a gross margin of 25%. For the Zaragoza bean study, it was 0.6%. It is a shorter marketing chain and only two actors intervene.

For the indicators of return, there were differences; for example, in Nigeria, labor participated with 72% of the total costs, meanwhile, for the dry Caribbean Region assessed in this study, it was 55%; moreover, when compared with the net income for Nigeria, the value was US$ 792.34, meanwhile for the Caribbean Region, it was US$ 513. It should be noted that the efficiency of the Zaragoza bean production system was evidenced by its profitability, explained by the fact that the income exceeds the costs. Other studies reported by ^{Martínez-Reina et al. (2019b)} had return indicators in the case of the eggplant production system for the humid Caribbean Region, with profitability values 51% higher than the one found in this study.

When analyzing the dynamics of the production chain around the distribution of surpluses of the difference between the price paid to the producer and the price paid to the consumer, it was observed that the indicators, marketing margins, and direct producer participation were lower than in other studies. Perhaps this can be explained because the marketing chain for the Zaragoza bean is shorter, and only two actors intervene, making the difference in the producer price and the consumer price lower than in the other species reported in several studies.

The aging of the rural sector, the field and agriculture is a reality. This situation was evidenced when studying the production of zaragoza beans in the municipalities of Rio de Oro in the Department of Cesar and Barrancas in La Guajira. According to the World Health Organization, in recent years, the proportion of people over 60 years of age has been increasing faster than any other age group in almost all countries (^{WHO 2015}). For Colombia, DANE reported that the percentage of rural inhabitants with ages close to 60 years has increased from 7% in 1985, which increased to 10% in 2014, and it is estimated that it will reach 23% by 2050 (^{DANE, 2010}). The data agreed with ^{López et al. (2018)} for the municipality of Chinavita in the Department of Boyaca. This phenomenon of aging for the Zaragoza bean study had an average age of 48 years, with maximum ages of 70. This puts at risk not only the production of beans but agriculture in general, along with the the low availability of public services and road infrastructure, which make production more expensive.