Dodo6/Topic_Modelling_using_LDA

1Article2 3Energy and Economic Efficiency of Maize4Agroecosystem under Three Management Strategies5in the Frailesca, Chiapas (Mexico)6Franklin B. Martínez 1, Francisco Guevara 2,*, Carlos E. Aguilar 2, René Pinto 2, Manuel A. La O 2,7Luis A. Rodríguez 3 and Deb R. Aryal 48Estudiante de Doctorado en Ciencias Agropecuarias y Sustentabilidad, Universidad Autónoma de Chiapas9(UNACH), Carretera Ocozocoautla—Villaflores Km. 84.5, C.P. 30470 Villaflores, Mexico;10franklinmar7820@yahoo.com.mx112 Investigador de la Universidad Autónoma de Chiapas (UNACH), Facultad de Ciencias Agronómicas.12Carretera Ocozocoautla-Villaflores Km. 84.5, C.P. 30470 Villaflores, Mexico; ceaj2001@yahoo.com.mx13(C.E.A.); pinto_ruiz@yahoo.com.mx (R.P.); pacholaoarias@gmail.com (M.A.L.O.)143 Investigador de Facultad de Ingeniería, Sede Villa Corzo. Universidad de Ciencias y Artes de Chiapas15(UNICACH), Carretera Villa Corzo-Monterrey Km 3, C.P 30520 Villa Corzo., Mexico;16luislarra2012@gmail.com174 Facultad de Ciencias Agronómicas, CONACYT-UNACH, C.P. 30470 Villaflores, Mexico;18debraj.aryal@hotmail.com19* Correspondence: francisco.guevara@unach.mx20121 22Received: 04 February 2020; Accepted: 10 March 2020; Published: 15 March 202023 24Abstract: Analysis of energy flows and economic dynamics allows the diversity of variables25involved in the agroecosystem production to be observed in the same dimension. In this way,26efficiency and performance can be analysed integrally to identify critical points to be improved.27The objective of this study was to analyse the energy-economic efficiency within three management28strategies (Management I, Management II and Management III) of the maize agroecosystem in the29Frailesca region of Chiapas (Mexico). The hypothesis was that systemic typologies, defined by30modes of production, can lead to different efficiencies for the system performance. The study was31descriptive; case studies were selected as representative based on their technological variants. The32efficiency analysis was conducted using a balance of inputs and outputs expressed in energy and33economic terms. Management III resulted in better energy use efficiency, with 6.47, while34Management I and Management II were more economically feasible, with a benefit/cost ratio of351.56 pesos.36Keywords: maize agroecosystem; energy balance; economic feasibility37 381. Introduction39Maize is one of the most important cereals for human sustenance [1], and its use has extended40to animal feeding and obtaining biofuel [2,3], resulting in demand for higher production. In Mexico,41production has increased 75% from 1980 to 2016, while the area cultivated under maize has42increased only 3% [4]. This increase is the consequence of genetic improvement of the species and of43technology based on synthetic fertilizers and other agrochemicals and machinery, which have44resulted in higher yield per unit of area.45In Mexico, maize is cultivated commercially and for home consumption by small farmers and46their families, who use different types of management for maize production [5,6]. Previous47Agriculture 2020, 10, 81; doi:10.3390/agriculture1003008148 49www.mdpi.com/journal/agriculture50 51Agriculture 2020, 10, 8152 532 of 1654 55researches in Frailesca (Chiapas) found, from a technological point of view, a diversity of56management strategies for the maize agroecosystem, and two productive visions were identified.57On the one hand, there is a conventional vision based on the use of a “technological packages”58approach towards agroecosystem intensification, which completely depends on industrial inputs59such as the agrochemicals, machines and commercial seeds. The aiming is the economic efficiency of60the agroecosystem. On the other hand, there is an environmental vision based on agroecological61approaches and promotes the minimum use of industrial inputs, recognises and uses local62technologies and seeks for the efficiency of the agroecosystem. However, there are in-between63perspectives where characteristics of both visions come together dynamically. Authors like Ocaña64[6] and Guevara et al. [7] conducted some studies on those technological aspects observed in both65visions as well as in the in-between perspectives.66This background settled up a scenario for the current study, taking into consideration the67findings regarding three management strategies for maize production in the region. Management I,68with permanent requirements of energy from fossil sources in all its production stages. Such energy69supports the agricultural components such as agrochemicals, machinery and water pumps for70irrigation, as well as for cultivation practices and harvest [8–10]. On the other side, Management II is71associated to agroecological practices and is characterised by greater dependence on labour, leading72to reduced industrial energy, incorporation of practices for soil conservation, intercropping and use73of residues from harvest. It is closer to a kind of traditional agriculture. In-between there is74Management III, combining elements from Management I and II, which uses some industrial energy,75integrates soil conservation practices and uses commercial seed varieties into the agroecosystem,76among other shared elements.77In the Frailesca, 88% of the growers use fertilizers and 76% use insecticides and herbicides,78representing a strong industrial energy component [7]. Moreover, 92% of the growers use improved79seed, while 8% prefer local seed [11,12]. These high industrial energy expenditures, as part of the80energy input in the production process, are closely related to greenhouse gas emissions (GGE)81[13,14]. This situation means that there has been a substitution of intangible process technologies82with a strong component of information and knowledge by technologies of inputs associated with83industrial development and, therefore, with higher economic costs [15–17].84For the above reasons, in the methodological context of systemic-energy analyses of85agroecosystems, two basic sources of energy are identified: ecological and cultural. The first comes86directly from the sun, while the second is attributed to all anthropic activity through agricultural87technologies. In turn, this cultural energy can have a biological origin (human work, animal work88and organic materials) or industrial (fossil energy, agrochemicals and machinery) [18,19].89In this sense, it is necessary to measure the energy flow in the system for production of a good90to determine the expenditure of energy and improve its efficiency [20] and, in this way, obtain a91product that is economically profitable and has less negative impact on the environment [21]. In this92sense, energy use efficiency would explain the dynamics of energy within an agroecosystem, ranch93or farm, by means of a balance between the energy invested, or energy inputs, and the energy94produced, or energy outputs [22,23]. To this end, the objective of this study was to conduct a95comparative analysis on the energy-economic efficiency of the maize agroecosystem under three96management modes (Management I, Management II and Management III) in the Frailesca (Chiapas),97under the hypothesis that systemic typologies, defined by the type of management, will lead to98different performance of efficiency indicators assessed from a systemic perspective.992. Materials and Methods1002.1. Location of the Study Area101The study was conducted in the Frailesca region of the state of Chiapas, which is located on the102Central Depression of the State, comprising the following municipalities: Villaflores, Villa Corzo, La103Concordia, Angel Albino Corzo, Montecristo de Guerrero and El Parral (Figure 1). It is characterised104by its important agricultural activity, especially by its area for maize production. The region’s105 106Agriculture 2020, 10, 81107 1083 of 16109 110climates are in the groups of warm and semi-warm. Warm sub-humid climate with summer rains111predominates, followed by semi-warm humid with abundant summer rain. From May to October,112average minimum temperatures oscillate between 12 °C and 21 °C. Rainfall during these months113oscillates between 1000 mm and 2600 mm. In the period from November to April, the average114minimum temperatures vary from 9 °C to 15 °C, with averages of 12 °C to 15 °C in 92.96% of the115region. During this period, rainfall is 25 mm to 30 mm [24].116The Frailesca is characterised by small farmers with plots for maize production up to 6 hectares.117Maize is cropped in annual cycles and is based on the rainy season, which is defined from June to118December. Traditional tillage techniques are employed by using local tools like the coa (planting119stick), hoe, machete and simple equipment such as sprinklers for the application of chemical120products. During the harvest season, corn small shelling machines are used too. The average maize121yield for the Frailesca is 3.5 t ha−1 and for the state of Chiapas the average maize yield is 1.9 t ha−1.122 123Figure 1. Location of the study area. Frailesca Region, Chiapas (Mexico).124 1252.2. Selection of the Study Region and the Farming Styles126The Frailesca was selected because it is one of the largest maize-producing regions of Chiapas in127terms of cultivated area. In this region, the maize agroecosystem is the productive base of the128families and is complemented with cattle and smaller species livestock. Maize production is both129monocropped and intercropped with other crops.130The farming types for the current study were determined by previous works conducted by131Ocaña [6]; Guevara et al. [7] and Guevara et al. [16] in order to focus on three basic management132strategies in the Frailesca: Management I, associated to conventional practices; Management II133related to traditional practices; Management III, related to intermediate management strategies and134placed in-between Management I and II. Moreover, proposition-interactive methods were used, in135discussion spaces among experts and farmers as suggested by Hagmann and Guevara [25] and136Guevara-Hernández [26] in order to figure out the basic elements of local farming.137Some characteristics from earlier studies were confirmed with a farmer’s typology developed as138complementary part of this research by considering variables such as: cropped area, labour used,139cropping objective, type of seed, fertilizer applied, herbicides used, insecticides spread, machinery140used and soil conservation practices implemented (Table 1). Field data was collected from farmers141through interviews and surveys. The typology and prior studies were the background to proceed142with the current analysis of energy-economic efficiency by focusing on the three maize management143modes. Therefore, 35 farms (11 for Management I, nine for Management II, and 15 for Management144 145Agriculture 2020, 10, 81146 1474 of 16148 149III) were selected for the study and monitored during a year for data collection. Such farms represent15010% of the total (300) used in a parallel study on sustainability assessment.151Table 1. Agroecosystem management modes for maize production in the Frailesca region, Chiapas.152Type of Management153and Technology154Soil preparation155Type of seed used156Labour157 158Synthetic inputs159 160Other practices161 162Socio-economic163Labour164Cropping objective (in165order of importance)166Profit167Cropping area168(average)169Land tenure170Level of protein171produced kg/ha/year172Protected forest area173 174Management I175Use of small agricultural176machinery plus herbicide177Hybrid178Family and paid179Intensive use of180herbicides181High amounts of182chemical fertilizers183Generalised use of184insecticides and185fungicides186Small agricultural187machinery for soil188preparation189Monoculture190 191Management II192Does not remove soil plus herbicide193Local 1194Family, paid and by invitation 2195Less use of herbicides196Lower amount of synthetic fertilizers197and use of local manures198Use of botanical techniques for pest and199diseases control, and minimal use of200synthetic pesticides201Soil conservation practices202Intercropping and crop rotation203Manual tools for weed management and204planting205Local knowledge on moon phases for206sowing and harvesting207 208Management III209Use of small agricultural210machinery plus herbicide211Hybrid212Family and paid213Intensive use of214herbicides215High amounts of216chemical fertilizers217Generalised use of218insecticides and219fungicides220Soil conservation221practices222Small agricultural223machinery for soil224preparation225Monoculture226 227Paid and family228Sale and family229consumption230Medium231 232Family, paid and by invitation233 234High235 236Family and paid237Sale and family238consumption239High240 2415.70 hectares242 2432.66 hectares244 2452.53 hectares246 247Ejidal (social) and private248 249Ejidal (social)250 251Ejidal and rented252 253High254 255Low256 257Medium258 259Scarce260 261High262 263Medium264 265Family consumption, animals and sale266 267Type of maize been growth or produced by the farmers themselves for more than five years,268regardless its origin. 2 Type of collaborative or supportive work among farmers to collectively carry269out high-demanding labour activities.2701271 2722.3. Analysis and Description of the Farming System273A systemic analysis was conducted by considering all the maize agroecosystem components, its274inputs and outputs, as well as the relationships between components according to Guevara et al.275[27]. A calendar of agricultural activities to figure out the activities in each production type was276drawn and used, according to the methodology described by Geilfus [28], and the annual cropping277cycle as reference.2782.4. Energy Balance279Regarding the energy balance a method of analysis proposed by Meul et al. [29], Funes [30] and280Cervantes [19] was used. The method determines cultivation energy inputs and outputs from281products of the system and expresses them in energy units to analyse the flows and obtain the282corresponding balances. The documented information was the following: cropped area, type and283quantity of food or other products obtained and direct or indirect energy expenditures in284production, such as human labour or animal work, fuels used, agrochemicals employed such as285fertilizers, pesticides, herbicides and other inputs used in the agroecosystem.286The energy equivalences in Table 2 were used as the basis for calculating energy efficiency. The287criteria presented by Márquez et al. [31] were considered for both direct and indirect energy used in288maize production. According to this author, direct energy is that contained in inputs: fuel, electricity,289 290Agriculture 2020, 10, 81291 2925 of 16293 294fertilizers, pesticides, organic fertilizers and biological products. Indirect energy is that associated295with processes of manufacture, distribution and maintenance Bowers [32].296Table 2. Energy equivalence of inputs and products analysed in the study.297 298Input299Human work300Animal work301Seed (in general)302Diesel303Gasoline304Ammonium sulphate (21%)305Herbicide306Insecticide307Machinery308Farm tractor309Product (Maize, dry grain)310†311 312Uni313Workday314Workday315Kg316L317L318Kg319L320L321Hours322Hours323Kg324 325MJ Unit−1 †3261.053277.54328107.6632938.7033034.1233145.03332238.65333184.2233487.923354.2533615.31337 338Source339[33]340[33]341[34]342[35]343[35]344[36]345[33]346[33]347[34]348[37]349[30]350 351The energy equivalents contain direct and indirect energy.352 3532.5. Calculation of Indicators for Energy Balance354In order to compare the three technological modes (Management I, Management II and355Management III) for maize production, the method proposed by Funes [33,38] and Pimentel [34] was356used for the measurement of energy efficiency in all the selected farms, and to analyse the flow of357energy input to the agroecosystem, as well as the amount of output. In addition, this method adapts358to the nature of the research. In this sense, different formulas were used for the quantification of359energy produced: protein produced/ha, number of people who may eat based on energy, number of360people who eat based on protein, energy intensity and energy efficiency:361𝑃 ∙ 𝐸𝐸362Energy produced for product i (MJ ha−1): 𝐸𝑃 =363𝐴.364where: EPi—Energy produced for the ithproduct, Pi—total production, EEi—energy equivalent and365Ai—total area for the corresponding product.366Protein produced for a product (Kg ha−1): 𝑃𝑃 =367 368𝑃 ∙ 𝐸𝑃369 370𝐴371 372where: PPi—Protein produced for the ith product, Pi—Total production, EPi—Protein equivalence373and Ai—total area for the corresponding product.374Number of people fed with energy (People ha−1): 𝑃𝐴𝐸 =375 376∑377 378𝐸𝑃379 380𝑅𝐸1381 382where: PAE—People fed by the system with energy per unit of area, EPi—Energy produced by383product i and RE1—Energy requirement of one person for one year.384Number of people fed with protein (People ha−1.year): 𝑃𝐴𝑃 =385 386∑387 388𝑃𝑃389 390𝑅𝑃1391 392where: PAP—People fed by the system with protein per unit of area, PPi—Protein produced by393product i and RP1—energy requirement of one person for one year.394Energy intensity (MJ.kg−1) energy required per kg of food produced:395𝐼𝐸 = 𝐸𝑈𝑇 𝑃𝑇396where: IE—Energy intensity, EUT—Total used energy, sum of inputs multiplied by their energy397equivalents and PT—total production in kg.398Energy yield (kg.MJ−1) Production obtained per MJ consumed:399𝑅𝐸 = 𝑃𝑇 𝐸𝑈𝑇400 401Agriculture 2020, 10, 81402 4036 of 16404 405where: RE—energy yield, EUT—Total used energy, sum of inputs multiplied by their energy406equivalents and PT—Total production in kg.407Used energy efficiency, Energy produced by each unit of energy consumed.408𝐸𝐸 = 𝐸𝑃𝑇 𝐸𝑈𝑇409where: EE—Energy efficiency, EUT—Total used energy, sum of inputs multiplied by their energy410equivalents and EPT—Total produced energy, sum of products multiplied by their energy411equivalents.4122.6. Economic Efficiency of the Farming System413To calculate economic efficiency, production costs as well as incomes from sale of the harvest414were considered. With data on incomes and expenditures, the Benefit/Cost ratio was calculated as415the indicator of economic efficiency using the formula:416Benefit/Cost = Incomes/Costs417Field data were obtained through direct interviews with farmers. The costs of agricultural418activities, inputs used in each activity, labour, economic value of crop yields and type of product419obtained were considered in order to evaluate energy inputs and outputs [39].4203. Results and Discussion4213.1. Characteristics of the Maize Production Modes422The three management modes studied (Management I, Management II and Management III)423were based on mono-cropped maize. They are carried out in one annual cycle and are rainfed; that424is, moisture is provided during the rainy season from June to December. Traditional work425techniques are used with typical tools such as the “coa” (planting stick), hoe, machete and simple426equipment such as sprayers for applying chemical products. For harvesting, maize de-graining427machines are used.428The use of agrochemicals is common to the three management types studied, but they differ in429magnitude of use. Management I is based on mechanised tillage, use of hybrid seed and high430quantities of agrochemicals, while the other two modes (Management II and Management III) use431local varieties, coinciding with the results published by Damián et al. [40] and Delgado et al. [12].432The quantity of industrialised inputs used differ in the three management types (Table 3).433Management I is characterised by intensive use of herbicides, insecticides, fertilizers and fungicides,434from seed treatment to crop growth and development. In the case of Management II, insecticides are435used to treat seed before sowing to control the borer Spodoptera frugiperda Smith during crop growth.436Traps with natural attractants are also used. In management III, herbicides are used in larger437quantities than in the other two modes, as well as insecticides, mechanised tillage and hybrid seed.438In all cases, growers sell most of the grain immediately after harvest. The rest is stored either on the439cob or as grain for home consumption and feed for backyard animals. By type and quantity of440agrochemicals used, the conventional and mixed modes are those that use more chemical products.441Table 3. Inputs used in a crop cycle/hectare for each type of maize management.442 443Input444 445Unit of446Measure447 448Seed (maize)449Diesel450Gasoline451 452Kg453L454L455 456Amount of Inputs Used ha−1457Management458Management I459Management II460III461Mea462Mean463S.E.464Mean465S.E.466S.E.467n468204690.000470204710.000472204730.000474104751.61247684772.646478104791.64848015 a4813.43548210 b4831.93648415 a4852.392486 487Sig.488 489ns490ns4910.00492 493Agriculture 2020, 10, 81494 495Ammonium Sulphate 21%496Glyphosate497Paraquat4982-4 D amine499Paraquat + Diuron500Methyl parathion501Aluminium phosphorus502Cypermethrin503Mancozeb504 5057 of 16506 507Kg508L509L510L511L512L513Tablet514L515kg516 517800 a5183.5 a5195a5203a5210c5222b5233a5243a5253a526 52763.2465280.54775290.9225300.4475310.0005320.7425330.6325340.7755350.632536 537600 b5381.5 b5391c5401c5413a5421c5430c5441c5451c546 54775.005480.5005490.5005500.0005510.5005520.4335530.0005540.7075550.707556 557800 a5583a5593b5602b5612b5623a5632b5642b5652b566 56770.7115680.68145690.7565700.6555710.6555720.4635730.7565740.7565750.756576 5770.005780.005790.005800.005810.005820.005830.005840.005850.00586 587Different letters in the same rows indicate statistical difference (p ≤0.05); Duncan (1955). S.E.:588Standard error; ns: Not significant, Sig: Significance589 590The use of fertilizers is another common aspect to the three types of maize agroecosystem591management. The difference lies in the quantity used; Management II uses the least (Table 3). This592agrees with [40], who mentions that the use of herbicides and fertilizers is common to all models of593maize production, both Management I and Management III. However, they differ in the quantities594used, in efficient use of nitrogen and in GGE [14].595Management II uses 20 kg ha−1 of a landrace seed known locally as “macho”. Seed is obtained596from the last harvest or is acquired from another grower of the same community if for some reason597the seed is lost. The cultivated area is generally one hectare with an average yield of 3411.1 kg ha−1.598Of the harvest, 93.8% is sold and the rest is used for home consumption and animal feed.599The system’s largest energy costs are from external sources, from acquisition of herbicides,600insecticides, fungicides, fertilizers and fuel used in land preparation and de-graining ears. This601coincides with Iermanó and Sarandón [41], who pointed out that agricultural production generates602an increase in the use of fossil fuel and its derivates. The energy from labour is that of the grower603himself, and only for some activities, such as sowing, fertilisation and de-graining, paid labour is604required. During the entire crop cycle, 137 workdays/ha are needed; of these, only 15% is paid since605the rest is supplied by the grower or his family.606Management I uses hybrid seed, 20 kg ha−1. On average, one hectare is planted for an average607yield of 4727.2 kg ha−1, of which 95.1% is sold and the rest is used for home consumption and feeding608the animals, generally, backyard poultry. Most of the energy used in the system comes from external609sources through acquisition of herbicides, insecticides and fertilizers. Labour used is 110610workdays/ha, of which 23% is paid the rest is family labour.611Management III is based on hybrid varieties as well as landraces. The amount of seed necessary612to plant one hectare is 20 kg (62,500 seeds/bag). The variety used is often attacked by pests and613diseases during the season of intense rains. Nevertheless, average yield is 4033.3 kg ha−1, 99.1% of614which is sold. Like the other two systems, most of the energy expenditure comes from external615sources, which include herbicides, fertilizers and fuel. The labour needed is 117 workdays/ha, of616which 19% is paid.617 618Agriculture 2020, 10, 81619 6208 of 16621 6223.2. Productive Cycle and Types of Management623The calendar of agricultural activities is similar for the three management types. The crop cycle624begins with sowing in June and early July after the rainy season has begun. In March and April,625“rastrojeo” (grazing animals in the plots where maize had been planted) is practiced, anti-fire gaps626are constructed, residues are burned and herbicide is applied. In the three modes of agroecosystem627management, fertilizer is applied twice, in July and August (20 and 40 days after sowing), while628herbicides are applied during June and July. Harvest is in December and occasionally postponed629until January or February of the following year. One article [42] gives a similar description and630highlights the harvest for the sale of grain and the care of seeds for the next crop cycle as important631aspects.6323.3. Use of Labour633Availability and use of labour in agricultural activities for each mode of production studied634vary and depend on both the activity and the day wages paid by the grower (Figure 2). Depending635on the activity, a full day of work is 6 h, for which 120 pesos (6 USD) is paid. For de-graining the636maize, work is around one hour, and the full day is paid. There are also communities where this637activity is done by invitation; the practice is collaborative and rotational for the grower that requires638additional labour at an agreed moment. In the case of labour provided by the grower of each639production unit, a workday can last 10 h, which means much longer workdays, which increase the640energy expenditure for the production system. When the land where the maize will be planted is641burned, the grower may work for 24 h to take the necessary measures to contain the fire and comply642with the regulations established by the National Commission of Natural Protected Areas643(CONANP, abbreviation in Spanish).644The activities carried out in each management type are differentiated by the number of working645days (6 h/day) used: Management I (110 days/cycle), Management II (137 days/cycle) and646Management III (117 days/cycles). Namely, 660 h, 822 h and 702 h, respectively, are needed for647maize production during a crop cycle. This is because in Management II, more working days are648used for grain-bagging and transport, but also because farms are located far from the sales centre.649Nonetheless, the three management modes share common points, e.g., in the number of workings650days used for sowing (6), fertilizers application (5) and fungicides application (3). These similarities651are based on established social representations among the farmers. In other words, these variables652are a kind of common factor for managing strategies in the Frailesca and based on a shared and653little-questioned knowledge. The results for Management I coincide with those reported by Delgado654et al. [12] and Purroy et al. [43], who found that within conventional management, more machinery655is used and the need for labour is reduced.656Management II concentrates 51% (70 workdays) of the total days employed for burning,657harvesting, bagging and transport; moreover, Management III invests 47% (55 workdays) of days for658the same activities. The results show that these activities are the most-labour demanding in both659management types. This agrees with Purroy et al. [43] in relation to labour demands for harvest,660bagging and transport.661 662Agriculture 2020, 10, 81663 6649 of 16665 666Figure 2. Labour needed for agricultural activities in three management modes for maize production667(workday/h) in the Frailesca region (Chiapas).668 6693.4. Energy Balance670From an energy perspective, the three modes of managing the maize agroecosystem have an671efficiency of one, indicating their energy feasibility. Management II had the lowest energy use672efficiency (4.65 MJ) because it generated a high energy expenditure, with 11,831.18 MJ ha−1, and673lower yield than the other management modes. These results contrast with those found by Funes et674al. [44], who indicated that in food production agroecological systems in Cuba, the least diversified675systems were the least productive, but they tended to be more energy efficient [45]. However, in the676Frailesca mono-cropped maize predominates under any management type. Additionally, the energy677efficiencies of Management I (6.04 MJ) and Management III (6.47 MJ) are very close to that reported678by Alemán and Brito [21] for mono-cropped maize with conventional management methods. In this679sense, both systems (Management I and Management III) increased the use of energy inputs,680suggesting that these inputs are used in order to be more efficient. This also coincides with Sánchez681and Romero [20]. However, Pimentel [46] stated that average energy use efficiency for maize is 41.84682MJ, produced for each invested MJ. This indicates that even under this criterion, in general, the three683 684Agriculture 2020, 10, 81685 68610 of 16687 688modes of management exhibit low energy use efficiency. For this reason, the study of agroecosystem689energy use efficiency can be used as a tool for characterizing and typifying these systems, according690to Purroy et al. [47] and Stark et al. [48].691The analysis of energy use intensity for the management types (I, II and III) in the692agroecosystem revealed that to produce one kilogram of maize, 2.87, 3.61 and 2.63 MJ, respectively,693are required. This shows that most farmers depend on fossil energy and on agrochemicals,694coinciding with results obtained by Pimentel and Pimentel [49]. Thus, the three management modes695are inefficient in terms of fossil energy use, which could be explained by deterioration of the soil,696timing of input application and distribution of rainwater at the critical stages of growth and697development of the agroecosystem. In synthesis, these systems are not sustainable in the long term698because the soil is constantly being degraded.699In terms of energy from agrochemicals, more than 50% of the energy expenditure depends on700that supplied by ammonium sulphate fertilizer. For the three types of the maize agroecosystem701management (I, II and III), around 36,024, 27,018 and 36,024 MJ, respectively, are used. This702coincides with IDAE [37], who demonstrated that nitrogen fertilizers are those that demand more703than half the energy cost of a crop.704Moreover, the higher energy cost is due to inputs such as herbicides and insecticides required705for pest and disease control. However, the energy contribution of these expenditures tends to be706compensated by the elimination of competition for the crop and of damage to the maize plant,707resulting in higher yield. Regarding the other inputs, such as fuel, the energy cost is low in the three708systems since it is only consumed by the ear de-grainer and the tractor for preparing the soil and709occasionally to transport the harvest. Valdés et al. [50], in a study on energy use efficiency of diverse710agroecosystems in Cuba, showed that the energy balance is significantly affected by external inputs711needed to maintain production.712Based on yields, Management I can feed more people per unit of area, in terms of both energy713and protein, than Management II or Management III (Table 4). This indicator has environmental714significance since growing social demand for food imposes a need to obtain yields that are sufficient715to slow the expansion of the agricultural frontier. These results coincide with Valdés et al. [50], who716stated that in energy terms mono-cropping high yielding crops produces large quantities of energy717that can feed more people per unit of area. Schiere et al. [51] showed that the number of people that718one hectare of land planted with a single crop (maize) can feed is 10.4, as energy source, and 5.4, as719protein source.720Table 4. Energy balance and potential for energy and protein production within three management721modes for the maize agroecosystem.722Management I723Mean S.E.724Production Factors725Planted area (ha)726Yield (kg ha−1)727Energy produced (EP) (MJha−1)728Protein produced (Kg ha−1)729Number of people fed ha−1/year730Maize731Protein sources732Energy consumed (EC)733Human and animal work (MJ ha−1)734Inputs used (MJ ha−1)735Energy intensity (MJkg−1)736Energy yield (kgMJ−1)737Energy use efficiency (EP/EC)738 739Management II740Mean S.E.741 742Management III743Mean S.E.744 745Sig.746 74717484727.2 a74973,760.18750465.85751 752368.757536044.1775441.77755 75617573411.1 b75854,982.67759362.53760 761407.667626682.0876346.17764 76517664033.3 a76765,387.8768434.30769 770315.777715175.9277235.77773 774ns7750.069776ns777ns778 77924.06 a78023.4078112,177.13 a782260.7278311,916.4 a7842.87 a7850.395 a7866.04 a787 7881.887892.09790439.9879124.05792430.747930.307940.007950.52796 79717.36 c79818.2179911,831.18 a800268.6680111,562.51 a8023.61 a8030.305 b8044.65 b805 8062.088072.31808486.4280926.59810476.208110.338120.008130.57814 81520.53 b81621.8281710,099.83 b818304.738199795.44 b8202.63 b8210.430 a8226.47 a823 8241.368251.79826376.7882720.60828368.868290.258300.008310.44832 8330.069834ns8350.002836ns8370.0018380.0348390.0398400.038841 842Different letters in rows indicate statistical difference (p ≤ 0.05); Duncan (1955). S.E.: Standard error:843ns: not significant. Sig: Significance844 845Agriculture 2020, 10, 81846 84711 of 16848 8493.5. Benefit-Cost Ratio850The total cost of Management I is higher than the others (Figure 3), mostly due to the high price851of the seed, fertilizers, land preparation and labour that the maize agroecosystem demands. Labour852and fertilizers account for 27% and 21.8%, respectively, of the total production cost. Management II853and Management III present the same tendency. The costs of agrochemicals make maize production854more expensive under the three management modes in the study area. The three types of855management (I, II and III) spend 54.72, 55.64 and 51.83%, respectively, of the total production cost on856agrochemicals, which has negative implications for the environment and indicates that they are857unsustainable practices, even though the profit margins may justify them economically.858 859Figure 3. Structure and percentages of economic expenses in three management modes for maize860production in the Frailesca region (Chiapas).861 862By percentage of commercialised harvest, grain yield, and sale price, Management I obtains the863highest economic gains (Table 5). This is due not only to higher yields, but also to the 95.1% of the864harvest that is sold. In contrast, Management II commercialises 93.8%, while Management III obtains865good grain yield and commercialises 99.1%, and is second place in terms of economic income.866Table 5. Yields and economic income by type of maize production in the Frailesca (Chiapas).867Mode of868Production869Management I870Management II871Management III872 873Yield(kg/ha)8744727.28753411.18764033.3877 878Quantity Commercialised879(kg)880450088132008824000883 884%88595.188693.888799.1888 889Price/kg890(pesos)8914.008924.208934.10894 895Income/ha896(pesos)89718,00089813,44089916,400900 901These results coincide with those obtained by Miranda et al. [52] and Mandal et al. [53], who902stated that mono-cropped maize systems have better yields in both economic gains and energy.903Management I and Management II have a better benefit/cost ratio of 1.56, while Management III has904one of 1.49. This means that, according to the economic feasibility analysis of the three management905modes, Management I and Management II are more feasible, with a profit margin of 0.56 per906invested peso (Table 6).907 908Agriculture 2020, 10, 81909 91012 of 16911 912Table 6. Economic feasibility analysis based on the benefit/cost ratio of three maize production types.913 914Income ($)915Expenditure ($)916Benefit/cost917 918Management I91918,00092011,4859211.56922 923Management II92413,4009258565.89261.56927 928Management III92916,40093011,002.79311.49932 933Several factors can affect economic feasibility, among which are high costs of external inputs934required by the three management modes and labour costs versus prices of the product at the time of935commercialisation. Additionally, low crop yields limit the energy use and economic efficiency of936these systems.937The three different management modes make use of fossil energy, one with greater intensity938(Management I), and has long-term consequences on natural resources, especially on the soil,939because it contributes to its degradation and automatically leads to a production capacity reduction.940In that sense, it is important to carry out soil conservation practices as indicated by Purroy et al. [54]941in order to promote the soil biodiversity and enhance the overall productivity of tropical942agroecosystems. Therefore, energy efficiency should be relaying on a better use of renewable energy,943because in Mexico, during the last 10 years the use of oil (sub) products in the agriculture sector has944significantly increased [55,56]. Despite national policies are recently promoting renewable energies945and products in agriculture but in an incipient and non-generalised strategy [57,58].9464. Conclusions947Three maize production strategies were confirmed in the Frailesca, Chiapas (Mexico):948Management I, II and III, which are practiced mostly under smallholder conditions. They use949landrace and hybrid seeds as well as intensive use of labour, whose economic costs oscillate between95026.99 and 39.69% of the total production cost. Management III was found to be the most efficient951from an energy perspective, while Management I has the highest capacity of protein and can feed a952larger number of people per hectare in one year, although it uses larger quantities of industrial953inputs in its production process. From an economic point of view, Management I and Management954II were more efficient in the benefit-cost relationship with 1.56 pesos; for each invested peso, there is955a profit margin of 0.56 peso. Although Management II did not present a high yield condition, its low956production cost made it efficient economically.957The inputs and supplies from industrial origins and non-renewable sources used in the maize958agroecosystem of the Frailesca are different in the three technological modes here analysed.959Management I is characterised by the intensive use of herbicides, insecticides, fertilizers and960fungicides, from the seed treatment to the growth and crop development. In Management II,961insecticides are used for the seed treatment before sowing. In Management III, herbicides are962commonly used in higher quantities—as well as insecticides—than the previous management963modes; mechanisation (small equipment) for soil preparation and commercial seeds are also utilised.964In the three management modes, most of the farmers sell the maize immediately after harvest; the965remaining maize is stored either on the cob or as grain for the family’s own consumption and used966for feeding barn animals. Regarding the type and quantity of agrochemicals, Management I and967Management III use the most. The use of fertilizers is another common and shared element among968the three management strategies and particular differences lie in the quantity used, being969Management II where minimum applications are required.970Author Contributions: Conceptualisation, F.G.-H. and D.R.A.; data curation, R.P.-R., M.A.L.O-A. and971L.A.R.-L.; formal analysis, F.B.M.-A. and M.A.L.O-A.; investigation, F.B.M.-A. and C.E.A.-J.; Methodology,972F.G.-H., L.A.R.-L. and D.R.A.; software, M.A.L.O-A.; supervision, F.G.-H. and C.E.A.-J.; Validation, R.P.-R. and973D.R.A.; Writing original draft, F.B.M.-A. and F.G.-H.; Writing—review and editing, F.B.M.-A., F.G.-H.,974M.A.L.O-A. and L.A.R.-L.975 976Agriculture 2020, 10, 81977 97813 of 16979 980Funding: This article was supported by the Programa para el Desarrollo Profesional Docente (PRODEP) from981the Ministry of Education of Mexico (SEP), which provided the funds to get it published. The authors are very982grateful to this institution.983Acknowledgments: This article is part of the doctoral dissertation entitled “Sustainability of the maize (Zea984mays L.) agroecosystem in the Frailesca region, Chiapas, Mexico” of the first author, who is grateful to the985Universidad Autónoma de Chiapas for its support and the opportunity to pursue the doctoral studies, PRODEP986programme for the scholarship granted and the farmers who directly and indirectly participated in this987research.988Conflicts of Interest: The authors declare that there is no conflict of interests between them and the journal, or989to any other instance or institution related to this research. This paper, due to the type of field work carried out,990does not present any ethical or bioethical implications. 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