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The present work is focused on the effects on the soil due to the traffic of sugarcane harvesting machines. The investigation took place in areas of three different units of sugarcane production in the UEB "Héctor Rodríguez", located on the north coast of Villa Clara. The CASE IH 8 800 harvesting machine and self-dumping car pulled by the Maxxum CASE 150 tractor were used for the study. The main characteristics of the predominant soils were determined, as well as the variations of soil micro relief, the bulk density and the soil moisture. The results showed soil modifications due to the traffic of the equipment during the harvest, highlighting the effect of the tractor and self-balancing aggregate. The machines introduce considerably modifications in field profile, by moving over and through the furrow, affecting the root zone. Dry bulk density values characteristic of heavy clay soils, were found, increasing this value after the harvesting machinery passing. On the other hand, soil moisture of 64.0% became in serious traffic problems for tractor self-balancing aggregates and causing traffic jam. [ABSTRACT FROM AUTHOR]

Draft force prediction and soil mechanical behavior during soil de-compaction was implemented by using the Discrete Element Method. The model parameters were defined as a function of the mechanical properties a clay soil, previously obtained by laboratory tests. The properties used by the model are cohesion, adhesion, internal friction, external friction, Young's modulus and Poisson's coefficient. The effect of the subsoiler shape variation was simulated under dry-compacted soil conditions, showing clear variations in forces related with the tool geometry. Increasing in complexity of the tool geometry the simulation, the model showed advantages in terms of demanded pressure and volume of soil disrupted. The soil de-compaction with hardpan formation was also simulated by introducing two different compacted soil sections in the virtual block. The compaction level was defined by two set of micro-particles with different density resulting from modifying the soil dry bulk density at the model macro-parameter. The simulation shows the feasibility of modelling separately the forces demanded for the different part of the tillage tool and the soil particle pattern of movement during the operation. [ABSTRACT FROM AUTHOR]

The general structure of the service for the technical assistance in the sugar cane soil tillage was based on three offers directed to the planning, the organization, the control and training: Technical attendance in the processes of soil tillage, Technical attendance in machinery management and Evaluation and trial of agricultural machines. This service is projected to reach the total area of the sugar cane crop in Cuba and to cover up the whole of the year. The attendance in soil tillage processes was applied to deforestation, land-leveling, fertilization and post-harvest field management, plantation and land preparation technological processes. For the planning of the farm works, the maintenance management and the machinery exploitation control a computer tools were programed. The recommendations given to the grower were technically based according to technological, energetical, economical and environmental approaches; taking in to account the results of more than 40 years of investigations of the INICA and other national institutions. To strengthen the material and human infrastructure of the INICA and to create a methodology for farm processes diagnostic on the service implementation was recommended. [ABSTRACT FROM AUTHOR]

Friction and cohesion in efforts that take place during soil deformation calculations. For interactions are considered normal force, tangential cohesive friction. The maximum shear is governed by the criterion of Mohr-Coulomb failure. Model calibration is performed by obtaining the relationship between micro and macroscopic parameters used in the model. The calibration of the friction was carried out by simulating the direct shear test of a sample of soil micro different friction coefficients. To calibrate cohesion used different values of cohesion at the micro and the relationship was obtained by modifying the micro friction values by simulating the biaxial compression test. The friction results showed a linear relationship regarding the variation of the micro value. Instead cohesion was linearly affected by the change in the quadratic micro-cohesion and friction over micro. [ABSTRACT FROM AUTHOR]

Central Valleys of Oaxaca, Mexico is among most densely populated state zones and most food consumed comes from the "milpa", a production system based on the exploitation of small extensions of up to 1,88 ha and the use of animal traction as a primary energy source for soil tillage. Given the importance of this problem it is developed this work for analyzing critically the current status of the use of animal traction in the Oaxaca Central Valleys. For completing this objective it was initially characterized the situation of crop production in this zone and analyzed tillage technology used in it. Finally it becomes clear the current employment situation of animal traction in the cultivation of these areas, specifying the problems of using wooden ards and metal ploughs. The results show the milpa production system, as a system of low-input based on crop association and in the employment of animal traction as a viable alternative to soil tillage, from the standpoint of technological and economic. It evidenced the need of replace the wooden plows by metal plows to fit the conditions and requirements of the milpa crop, which also enables the exchange of tools and keep the good features of traditional Mexican ard in terms of manageability, weight and versatility. [ABSTRACT FROM AUTHOR]

Discrete Element Method (DEM) was used to simulate the soil-tool interaction. The model is based on the action of normal, shear, cohesion and friction forces into the cohesive granular medium, calculated as a function of micro-mechanical properties. Macro-mechanical properties of soil-soil and soil-metal were used to determining the micro parameters on the model. In order simulate the tillage operations a soil virtual block was generated in hexagonal compacted array using 45 000 spherical particles forming a cohesive block. A soil-bin installation was conditioned to measuring the draft force in hard-dry and soft-wet soil condition to compare the results with simulation tests. The comparison showed a small under predicted behavior of the model for soft-wet soil; however the results become more accurate toward hard-dry soil conditions. The density changes during simulations and pressures distributions below the tillage tool path is showed, given a dynamic representation of soil internal tension and loosening after tillage operation. [ABSTRACT FROM AUTHOR]

Specific information about physical-mechanical properties of soil is a support for simulation by computation techniques as Finite Element and Discrete Element methods to predict the soil behavior during soil tool interaction. Determination of basics mechanical properties needed for mathematical modeling of clay soils on the arable layer were carried out using triaxial compression and modified shear box test. Variations in shear strength, Yong's modulus, internal friction angle, soil-metal friction angle, cohesion and adhesion were determined at different experimental levels of gravimetric water content and soil dry bulk density. Multi-factorial regression analysis to estimate the corresponding values of above properties was performed resulting on statistical prediction equations for all basic mechanical properties under study. [ABSTRACT FROM AUTHOR]

The present work was carried out in the basic unit of rural production, “El Palmar”, belonging to the Company of Mixed Cultivations “Pacquito Rosales Benítez” in the municipality of Yara (Granma. Cuba) during the months of April (2007) to January (2008). The method used was the investigative-analytic one with the photometric technique. There were evaluated the farm groups (tractor-agricultural implements) that employed in four farm technologies (T1, T2, T3 and T4) for the cultivation of the yucca, Rosy Dwarf variety. They were done five observations of the Labor Day for each one of the farm groups aimed to evaluate the fuel consumption and their productivity. The best results in the evaluated indicators corresponded to the technology of minimum ploughing, T2, with a Modified Subsoiler Bayamo and with a disk harrow. In T2 the productivity per hour of net time was 1,34 ha h-1 and the operational-time productivity was 1,27 ha h-1. T2 technology showed other significant differences regarding the rest of the evaluated technologies: it registered the smallest consumption of fuel (32,4 L h-1); that is, 72; 52 and 71 % less than T1, T3 and T4 farm technologies. [ABSTRACT FROM AUTHOR]

Animal traction as an energy source has a wide use in agriculture in Oaxaca, Mexico. For this reason we developed a new animal-drawn plough to perform various operations required for tillage. For optimization purposes it was necessary to analyze the strength of the structural elements of this plough through the finite element method. As a first step the geometric model was developed with the software Cosmos DesingStar 2008, and the definition of the mechanical properties of materials used in the construction of the plough and the definition of boundary conditions and loads. The results showed that the structure resists the loads applied during operation with a safety factor of 2,46, the magnitude of the resulting deformations was limited to 0,0005 m. Showing that the materials used in the construction of the plow ensure the strength and stiffness required to work without fault of its elements and working bodies. [ABSTRACT FROM AUTHOR]

A research was carried out in a Gley Vertic nodular soil of the north coast of Villa Clara province aimed to evaluate the effect of different technologies of soil preparation over weeds germination in the first period of sugar cane development. The results indicate, that the best control of total weed germination was found in stripe tillage. The no burning and the presence of trash residues in the soil surface after soil preparation allowed a better control of annual and liliatae weed, stripe tillage made a better control of perennial weed reproduce by seeds, meanwhile the use of technology that turned up the soil layer stimulate the germinations of magnoliatae weed. [ABSTRACT FROM AUTHOR]

In this work is evaluated the increase of the abrasive wear resistance in the work surfaces of the implement after applying the superficial recharge with submerged arch welding method (SAW). Were used two variants of ceramic flux, obtained from the slag welding rebuilding. The micro-hard tests, macro-hard test, metallographic structure and abrasive wear test are carry out, to study the behavior with the different deposits. The wear coefficient is determined in field conditions, using a real implement in a highly abrasive soil. [ABSTRACT FROM AUTHOR]

In this study, the required draft of an integral, reversible three-disks plow was studied on a loam clay soil. The experimental design was a random, three complete block design with three repetitions. The factors under study were three levels of gravimetric humidity in soil, 10,02, 19,74, and 22,39 %, and three speeds, 4,55, 5,27, and 7,34 km · h-1. The response variables were work depth, cross-section area, sliding, required specific draft, draft efficiency, and specific draught resistance to ploughin. The results show that when the gravimetric humidity of the soil was at 19,74 %, variables FTHER and REA showed the lowest values, but EFTHER showed the tallest value at same level humidity. Models that adequately estimate FTHER and REA were obtained. [ABSTRACT FROM AUTHOR]

In this study, the work quality of an integral, reversible three-disks plow was studied on a loam clay soil. The experimental design was a random, three complete block design with three repetitions. The factors under study were three levels of gravimetric humidity in soil, 10,02, 19,74, and 22,39 %, and three speeds, 4,55, 5,27, and 7,34 km h-1. The response variables were plant cover, residue incorporation index, bulk density, coefficient of expansion, and strength of the shear vane, depth and width of work. The results show that the best work quality was obtained when the gravimetric humidity of the soil was at 19,74 % y 22,39 %. [ABSTRACT FROM AUTHOR]