The relationship between machine and soil
H. Mahboub Yangeje; A. Mardani
Abstract
IntroductionSeedbed preparation, seeding, and transplanting are usually based on mechanical soil tillage. Tillage by cutting, mixing, overturning, and loosening the soil can modify the physical, mechanical, and biological properties of soil. These days, because of soil protection, the use of tillage ...
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IntroductionSeedbed preparation, seeding, and transplanting are usually based on mechanical soil tillage. Tillage by cutting, mixing, overturning, and loosening the soil can modify the physical, mechanical, and biological properties of soil. These days, because of soil protection, the use of tillage tools is less and less recommended, and some implements such as cultivators are preferred to primary tillage tools such as plows. Experimental study of soil-tool interaction and field measurements of the mechanics of tillage tools are usually time-consuming and costly. On the other hand, the variety of variables and uncontrolled conditions add other dimensions to the complexity of this method. Also, the experimental and analytical methods do not have a comprehensive view of stress distribution and soil deformation in the soil-tool interaction process.Materials and MethodsThe main purpose of this study is to validate the results of numerical simulations in two phases of experimental tests: in soil bin environment and in finite element computer simulations. Experimental tests were performed in the soil bin environment of the Department of Mechanical Engineering of Biosystems, Urmia University, which has a soil bin facility with dimensions of length and width of 24 and 2 m, respectively, and has clay loam soil. Before experimental tests, soil preparation was performed by using some special tillage implements (harrow, leveler, and roller) which were attached to the soil bin (Figure.1). For experimental tests, a mechanism set consisting of two cultivator blades with a width of 15cm, a length of 20cm, and at a spacing of 35cm from each other was prepared and constructed. The relevant mechanism is designed to have the ability to change the tillage depth. Data were collected at three different soil depth levels of 6, 10, and 14cm in the soil bin with three replications. Data recording was performed using a 10-channel data logger with load cell connectivity and data storage ability. Also, in this study, the Drucker-Prager model as a finite element simulation method was used to calculate the stress during the soil-tool relationship. ABAQUS 6.10.1 software was used to simulate the cultivator tine. To solve the problem, the soil parameters were defined as presented in Table 1, and then the interaction between the soil-tool model and the necessary constraints, including boundary conditions, were defined. In the next step, meshing was applied to the constructed model.Results and DiscussionIn the results section, first, the results related to the amount of traction force required for the tillage tine in the simulation were calculated and then compared with the soil bin experimental tests. The traction force of the finite element simulation results for three tillage depths of 6, 10, and 14 cm in three principal directions is shown in Figure 4. A comparison of simulation and experimental results showed that there is a good agreement between them. In comparison, the simulation error range of the three depths of 6, 10, and 14 cm has shown 7.3, 5.6, and 4.16% at a speed of 2.5 kmh-1, respectively, as the velocity studied in this research. In the next section, the results of stress distribution contours in the soil and finally the overlap of the blade effect were discussed. Figure 6 shows the status of stress contours at three depths. By increasing the depth of the tine at the three depth levels studied, the stress range is shifted from the soil surface to its depth. For this purpose, at the maximum depth studied in this study (14 cm), it shows that the stress propagation to the soil surface is less than at other depths. Also, with decreasing depth, for a depth of 6 cm, the maximum stress was on the top soil surface, in other words, more deformation was seen on the soil surface.ConclusionComparing the simulation results for predicting traction force with the results of experimental tests has led to relatively acceptable results and the maximum traction force prediction error at different depths has been about 7.3%.The distribution of stress in the soil was observed due to the tine depth. The highest intensity of stress propagation was observed at the soil surface; and the highest soil surface deformation at a depth of 6 cm. With increasing depth, both parameters of stress and soil surface deformation have decreased. According to the results of the studied blades, it is better to use these types of tillage tools only at lower depths. Also, in evaluating the overlap of the soil loosening zone in the side-by-side tines, it proves the superiority of the tine performance at lower depths.
A. Heidari; A. Ghadami Firouzabadi
Abstract
Introduction: Conventional tillage is widely used in sugar beet growing areas. However, conventional farming uses more labour and machines that has a negative effect on soil and the environment. Due to limited water resources and recent droughts, proper use of modern tillage and irrigation methods can ...
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Introduction: Conventional tillage is widely used in sugar beet growing areas. However, conventional farming uses more labour and machines that has a negative effect on soil and the environment. Due to limited water resources and recent droughts, proper use of modern tillage and irrigation methods can increase water efficiency and prevent soil degradation as a result of sustainable agriculture.Materials and Methods: An experiment was conducted to investigate different methods of tillage and water requirements on quantitative and qualitative yield and sugar beet water productivity in the drip irrigation system in Ekbatan Research Station of Hamedan Province from 2018 to 2019. A strip plot experiment with sixteen treatments and three replications was used. Tillage methods in four levels, consisting of T1- plowing with moldboard plow to a depth of 25-30 cm in autumn + power harrow to a depth of 15-20 cm in spring, T2- subsoiling to a depth of 35-40 cm + plowing with moldboard plow to a depth of 25-30 cm in autumn + power harrow to a depth of 15-20 cm in spring, T3- plowing with chisel plow equipped with roller packer to a depth of 25-30 cm in autumn + power harrow to a depth of 15-20 cm in spring and T4- plowing with sweep plow equipped with roller packer to a depth of 25-30 cm in autumn + power harrow to a depth of 15-20 cm in spring and Irrigation factor consisting of I1-100%, I2- 90%, I3- 80% and I4- 70% sugar beet water requirement were considered. Soil penetration resistance (PR), the volume of water consumption, root yield, sugar yield, white sugar yield and molasses were measured. Water efficiency in tillage and irrigation treatments was also calculated. MSTAT-C software was used for statistical analysis of data. The Duncan's multiple range test at a 1% probability level was used to compare the means.Result and Discussion: At a depth of 0-30 cm, no significant difference was observed between tillage methods on soil penetration resistance. At greater depths (35-40 cm) T2 treatment (subsoil + moldboard plow) had the greatest effect in reducing soil resistance. The results showed that the effect of different tillage methods, water requirement and their interactions at the 1% probability level on root yield; sugar yield and white sugar yield were significant. There was no significant difference between sugar beet yield in the T4 tillage treatment and the conventional method (T1). Treatments T4 (with an average yield of 50686 kg ha-1) and T1 (with an average yield of 50507 kg ha-1) had the highest sugar beet root yield. Also, the tillage method (T4) compared to the conventional tillage method (T1) reduced fuel consumption by 14.7% and increased field capacity by 52.4% respectively. In the T4 tillage method, irrigation treatments I100, I90 and I80 with mean water productivity of 6.113, 6.087 and 5.523 kg m-3 of water consumption, respectively, had the greatest effect on increasing water productivity, while no significant difference was observed between them.Conclusion: The tillage method (T4) compared to the conventional tillage method (T1) reduced fuel consumption by 14.7% and increased field capacity by 52.4%, respectively. There was no significant difference between sugar beet yield and water productivity in the T4 tillage treatment and the conventional method (T1). Although full irrigation treatment (100% water requirement) has the highest water efficiency, there is no significant difference between 90 and 80% water requirement treatment. Therefore, in order to save water consumption, 80% water requirement is recommended. The result is that in the T4 tillage method with a supply of 80% water requirement of sugar beet after plant establishment (approximately from the middle of the growing season) about 12% (1207 m-3) in water consumption without significant reduction in water productivity.
