This paper exposes an extension of the simplest mathematical model of soil organic matter decomposition. The equation of this model is very common in the literature, for example, Davidescu and Davidescu (1981), or Willigen et al. (2008), considering some

organic matter, time, evolution, mathematical, mode

Prognosis on Concentration of Soil Organic Matter Using Maps of Organic Matter Distribution and Progress Mathematical Models

This paper presents a method of prognosis of organic matter content evolution in a plane agricultural surface soil, using the information obtained by initial scanning with spectrophotometrical techniques. The scanning result – map of organic matter content distribution – is used as initial moment distribution for calculating the evolution of soil organic matter content in terms of time. In order to calculate the evolution in time of organic matter quantity, mathematical models described by differential equations known in specialty literature are used: Willigen et al. (2008 are used. .Knowing this evolution, we are able to evaluate the optimum moment applying and the fertilizer quantity necessary for obtaining the appropriate parameters of soil nutrients. Therefore, this method aims at predicting the evolution of organic matter content in an agricultural soil, on a plane surface, for being able to add in due time the chemical fertilizers treatments needed

Vector Representation for the Soil Erosion Model USLE,

This article presents a mathematical viewpoint as vector form on estimating the risk of erosion due to water action, starting from the original USLE. We started with a vector representation of pluviometric regime. Daily amount of rain during a year can be in the form vector graphics. This representation is equivalent to a vector. Starting from this representation is computed the factor of the rain erosivity. We found that other factors in the USLE formula allowed the same type of representation. These representations have been used in the daily calculating for the erosion. This point of view extends the USLE model using to the rainfall event erosivity assessment, similarly with the RUSLE models. This vision permit the comparison between the possible divisions of the annual period: month, weeks, days, hours, minutes or seconds. In this article the solution test are made by comparison of the result with experimental results obtained in the Valea Calugareasca vineyard

Estimating the Efficiency of Anti - Erosion Agricultural

The efficiency of the anti - erosion agricultural operations is one of the main objectives of the designers for machinery and soil working tools on slopes. Mathematical modelling that using a systemic approach of the phenomena and processes and realistic assumptions, allows the optimum constructive-functional parameters for soil working tools, in order to achieve a properly working with low energy consumption. Storage capacity of the sediment profiles achieved by ground shaping is properly estimated according to the geo - climatic conditions of the area. Previous researches (Cardei, Cota, 2008) led to the establishment of a calculation model in this respect. The method of calculation for choosing the geometry of profiles is the application of the final investigations, in conditions to assure a satisfactory storage capacity of sediments and a minimum energy consumption for the soil working processes

SUPPLEMENTS TO THE PROBLEM OF ENERGY CONSUMPTION IN REDUCING LIGNOCELLULOSES BIOMASS SIZE TO PRODUCE ENERGY

This article presents complementary results on experimental data on the process of reducing the size of plant biomass by mechanical cutting. According to the source of the experimental data, the problem of statistical modelling of the main parameters describing the process of biomass reduction was approached. A more comprehensive formulation of the list of main system parameters was also attempted, which should be considered in a minimal mathematical model. The results of this article are starting points for a systemic approach to this biomass processing process. A first systematization is fixing 13 parameters that are included in the model of the biomass size reduction phenomenon. The 13 model parameters are divided into three categories: input parameters (5), adjustment parameters (4) and output parameters (4). The performances of the interpolation formulas are evaluated using the global error and the maximum error, varying between 1% and 0.1% for the prior and 3.8% and 0.34% for the latter. Some mathematical models suggest the existence of optimal operating points. Their exploitation can only come as a result of new high-resolution experimental research, at least in terms of rotation speed

SOLIDWORKS 3D PARAMETRIC MODELLING TECHNIQUE FOR ROOT CUTTING EQUIPMENT DECLINING GROWTH OF SHOOTS IN ORCHARDS

This work was focused, by using computer aided engineering application (SolidWorks) and structural simulation (SolidWorks SIMULATION), on obtaining a technical and economic strength indicator used in the analysis of metallic material choice from which is made active body large diameter disc knife type, that equips the technical equipment for soil tillage on trees row, while cuttings root for moderating growth of shoots and precision foliar fertilization. For this purpose, on the 3D parametric modeling were selected from the software library various metallic materials, followed by finite element analysis (FEA) which was carried out to simulate the distributions of stress and strain on the body active. Based on the resulting data, were determined the reports price- coefficient of resistance for the materials analyzed. Comparing these indicators led to the selection of a material that has high resistance under a price as low as possible. Analysis based on technical and economic choice of a metallic material reduces the time validation of the design, by eliminating the realization and physical testing, and allows management to determine the existing resources in the company in order to use their total for achieve economic and financial results as high

Evaluation of transfer and bioaccumulation factors of heavy metals in different parsley samples

Heavy metals transfer factors help to observe metals impact on agricultural products (vegetables and/or fruits) to evaluate different bioaccumulation scenarios to interpret available experimental results and for designing fingerprints or bioaccumulation maps. The aim of this study was to evaluate the transfer factors (TF) of some heavy metals (HMs) including (Fe, Mn, Zn, Cu, Ni, Pb and Cd) from soil to root and leaves of parsley samples cultivated on polluted and nonpolluted areas and to identify the fingerprint of transferred metals. The heavy metal (HM) content was analyzed using Flame Atomic Absorption Spectrometry (FAAS) technique. The bioaccumulation factor (BF) and TF in parsley samples were used for obtaining the fingerprints (HMs bioaccumulation maps) of parsley samples

This paper exposes an extension of the simplest mathematical model of soil organic matter decomposition. The equation of this model is very common in the literature, for example, Davidescu and Davidescu (1981), or Willigen et al. (2008), considering some

organic matter, time, evolution, mathematical, model</jats:p

A Way of Estimating the Intensity of Connections Between the Parameters of a Dynamic System

In many cases, the influence of some of the characteristic parameters of some systems becomes important in relation to the influence of the other parameters, only when certain critical operating regimes are exceeded. These operating modes are often intangible in normal operation. In order not to endanger the system or to avoid the use of exaggerated power sources, the investigation of the influence of the parameters targeted in these critical operating regimes can be done by simulation, theoretical, experimental or mixed. The results are then subjected to a statistical analysis which may indicate a possible major change in the influence of some of the targeted parameters in the operation of the system. Specifically, the dynamic system considered is an agricultural machine for soil processing, consisting of a combinator and tractor. The simulation is done using a Goriacikin-type formula, which ensures complete theoretical control over the influence of the targeted parameters on the dynamic process of the machine. The parameters we focus on are working depth and working speed. The difference in intensity of the influence of each of the parameters is highlighted, trying an explanation for this difference. The explanations are useful for researchers who want to obtain information about the parameters whose influence on the functioning of the systems is small in the normal working regime but they can grow appreciably in the extra normal working regimes, even if for a short time.</jats:p