Social component

The average age of the heads of family surveyed is 55 years, with 5.5 years of schooling, 25.7% of the interviewees acknowledged not having any school year, 78.6% of the producers know how to read and write, 27.2% attended at least four years of study, 31.4% completed primary school and others (15.7%) presented between 9 and 12 years of schooling (Figure 1).

Figure 1 Level of education as a social component in the municipality of Tierra Blanca, Veracruz. 

In this respect, ^{Alvarez et al. (1985)}, mention that the level of schooling is associated with a greater use of technology and that increasing schooling increases the income. The average number of members of the families is five, 50% of the households have between one and four members and the other 50% have between five and eight. All the interviewees are engaged in agriculture, however in the case of women (30%) they also did housework and raising animals; 2.9% is also a student and 2.8% guaranteed to do extra work on the farm as a day laborer or employee with payments ranging from $150.00 to $200.00 a day. The execution of agricultural and non-agricultural activities has always been a basic survival strategy for peasant families (^{De Grammont, 2009}).

Agricultural component

The average surface of the properties that the interviewees possess was 11.28 ha, the minimum of 1 and the maximum of 12 hectares destined to different productive activities, of which 2.5 ha are for the cultivation of corn, 94.3% of the producers mentioned to be owners of these lands; however, 4.3% indicated that they lend their properties and 1.4% give them in rent. The usufruct of the land is: 90% ejidal and 10% small property, with respect to the humidity regime, 94.2% of the producers carry out temporary agriculture and the rest have some irrigation system. In the state of Veracruz, they are engaged in the cultivation of maize in an average of 200 thousand producers, most of them sowing from 1 to 3 hectares, located mainly in marginal regions and with medium or low productive potential and whose destination of production is basically self-consumption (^{Palafox et al., 2013}).

The 85.7% of the respondents said that the maize storms are made in the months of June July when the rainy season begins, the use of improved seed in the municipality is 94.3% and the rest corresponds to the use of creole materials 90% of the seed used by respondents comes from the City Council through the Municipal Rural Development Secretariat of Tierra Blanca, which is offered to producers through economic subsidies, i.e. the city subsidizes 50% of the real price of the seed, the other 50% is paid by the farmer, the sowing method that presented the highest frequency of use in the study area is the speck, as represented by 71.7% of the interviewees.

Corn production technology

In Mexico, around 8 million hectares are planted each year, of which 2.5 million correspond to the tropical region. In the state of Veracruz, the area sown is 530 thousand hectares with an average yield of 2 t ha^-1. The sowing is distributed in two agricultural cycles, 380 thousand hectares in rainy or spring-summer and 150 thousand of residual moisture (Tapachole) and irrigation that develop during the autumn-winter cycle (^{Palafox et al., 2013}). In the localities where the research was conducted, the results showed that in 2015 the area cultivated with corn was 197 hectares, of which 177 hectares were cultivated for grain and 20 hectares for fodder.

The agronomic management of the crop includes practices of: soil preparation, date of sowing, cultural work, density of sowing, application of fertilizers and pesticides, among others that the producer carries out during the crop cycle and the way in which they are combined the factors of production in each of the practices (^{Palafox et al., 2013}), in this sense 75.7% of the respondents made the passage of a harrow, 74.3% of the producers applied at least one herbicide prior to sowing, and the furrow was performed by 58.6% of the population under study. With regard to cultural work or crop maintenance, 97.14% of the producers made at least one fertilization and 58.6% of the interviewees applied some insecticide to control crop pests. The main fertilizer used by producers is urea, 87.1% of respondents reported, followed by ammonium sulfate with 17.1% and diammonium phosphate-DAP with 11.4% in the study area, Table 1 shows the number of producers and the type of fertilizers they use in the seasonal corn crop cycle.

On the other hand, the results of the estimation of maize yields of rainfed in the study area were 2.8 t ha^-1 with an average population density of 31 948 plants ha^-1, in this respect the town that obtained the highest yields was the locality of “Nuevo Arroyo Tambor” with 4.13 t ha^-1 with an average density of 49 395 plants ha^-1 (Table 2).

One of the factors related to the low production of corn is the density of plants, Tinoco et al. (2002), indicates that for improved varieties of low and intermediate size should be used about 62 500 plants. The population density is considered as the most important controllable factor to obtain higher yields in crops.

Planting density in maize exerts a high influence on grain yield and agronomic characteristics, since grain yield increases with population density until it reaches a maximum point and decreases when density increases beyond this point. Sangoi (2000), indicates that population density is one of the factors that often changes the producer to increase grain yield, however if population densities are used greater than the optimum increases the competition for light, water and nutrients, causing reduction in root volume, number of ears, amount and quality of the grain per plant and increase the frequency of root and stem rots, which favors low population densities cause problems with weeds or waste of soil (^{Maya and Ramírez, 2002}; ^{Njoka et al., 2005}).

The correlation analysis (Figure 2) of the variables plant density and average yield t ha^-1 indicated that there is a positive correlation (r= 0.98; p= 0.01), while the regression analysis showed a linear trend (R²= 0.96; Y= 0.0677x + 0.482); however, the relationship between grain production and population density is complex, since the best response in grain yield varies according to the condition of soil, climate, cultural practices and genotype (^{Pinter et al., 1994}; Sangoi, 2000), work done on population densities in maize hybrids under temporary in the humid tropics showed that increasing the density from 50 000 to 62 500 plants ha^-1 obtained the highest grain yield since the yield increased by 0.30 t ha^-1 (^{Cano et al., 2001}). On the other hand, ^{Carrera and Cervantes (2006)} reported that the yield increased 0.6 t ha^-1 by increasing the population density from 60 000 to 70 000 plants ha^-1.

Figure 2 Effect of population density on average yield t ha^-1 of seasonal maize in the municipality of Tierra Blanca. 

Production, consumption and sale of grain

Corn is a key crop for Mexico, in the period 2016-2017 the consumption of corn grain in the country was approximately 38.7 million tons of which 23.3 million tons corresponds to white corn and 15.3 million tons is yellow corn (^{FIRA, 2016}), the producers related to the research, stated that of the total production of grain they obtain, they reserve an average of 1 800 kg ha^-1 for family self-consumption but the producers affirmed that on average they buy 690 kg of maize for human and animal consumption generally in the months of September and October, 34% of respondents produce corn solely for self-consumption, while 66% of producers sell corn in the town or in the municipal seat, 85% of these said that the grain of corn they buy has lower quality compared to the one they produce and sell, however, the corn was sold at an average of $3.50 kg, and they bought it at $5.00 kg; that is, the product is losing on average $1.5 kg of purchased corn.

Livestock component

The raising of animals in rural areas and mainly of small producers constitutes a survival strategy that is related to agricultural activities and that together are aimed at the food sovereignty of producers, the result of the surveys showed that producers have total 2 022 animals, including birds (chickens), cattle (cows, bulls, calves), sheep and pigs, being Lazaro Cardenas the town that has the largest number of hens with a total of 259 birds/town, Villa Plan presented 103 heads of cattle/locality, Loma Caballo a total of 36 porcines/locality and The Prietas reached 29 sheep/locality. In Figure 3, it presents in summary the type and number of animals by location.

Figure 3 Number of animals by location in the Municipality of Tierra Blanca, Veracruz. 

^{Castaños (2009)} assures that the backyard livestock is a system characterized by the raising of a group of animals such as birds, horses, cattle, pigs, goats, sheep and cattle, the importance of livestock for peasant families lies mainly in that the products obtained can be used for self-consumption, and in case of economic necessity, they are used for sale, partially ensuring the survival of the family (^{Gutiérrez, 2007}). Raising pigs (Sus scrofa ssp.) generates income from their sale on foot, most of them are fed with waste or kitchen and harvest leftovers. Likewise, sheep (sheep) (Ovis aries), goats (Capra hircus), hens (Gallus gallus) and turkeys (Meleagris gallopavo) are part of the diet of the producers, they are the main food at parties, which have a great importance in these communities, given that it is through this type of events that the peasant family as a social unit maintains and consolidates networks and relations with other farmers (^{López et al., 2012}).

Under these considerations, it was determined that the raising of the animals of the producers of Tierra Blanca constitutes a strategy that provides food for self-consumption in addition to becoming a means to solve some type of need, in this sense 84.3% of the producers raise chickens with an average of 17 birds/producer, 96.6% of these animals are reared under backyard or solar conditions, likewise, the surveys showed that 61.4% of the people who participated in this research have an average of 6 cows/producer, 58.6% of cattle are reared in paddocks adjacent to the site, pigs (47.1%) are reared in lots or backyards, 58.6% of producers have an average of three animals. In the Table 3 shows the type of livestock and the frequency of producers who are also engaged in the cultivation of corn to raise animals.

On the other hand, 52.6% of the producers said that when corn production has good yields this helps to solve animal problems such as feeding, investment and disease control because they manage to satisfy the nutritional needs of the animals, In addition, there is availability of capital to make investments to improve the breeding of their animals as well as to control diseases, 31.6% indicated that these problems can be aggravated when there is no good production of corn and 15.8% said there is no relation between the yield of corn and the problems of the animals.